JPS6025471B2 - Display device driving method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving a display device using a liquid coloring material.

The present invention was based on the discovery that when a compound known as an organic scintillation reagent is dissolved in an organic solvent, an electrolyte is added, and a direct current is applied, the cathode surface develops a very bright color. It has been done.

Conventionally, an electrolytic cell having at least two electrodes in a medium consisting of an inert solvent, a fluorescent organic compound (e.g., an organic scintillation reagent), and a supporting electrolyte is contacted with an alternating current of sufficient voltage, and at least one electrode is The fluorescent organic compound is converted to the corresponding oxidized or reduced state by losing or gaining at least one electron, and the alternating current has a sufficient potential change with reversal of the alternating current cycle to convert the fluorescent organic compound into the corresponding oxidized or reduced state by losing or gaining at least one electron A method for producing useful visible electroluminescence in an electrolytic cell characterized by providing a sufficient amount of energy to regenerate a compound to its singlet excited state (e.g., Japanese Patent Publication No. 42-2199
(see Publication No. 1) was publicly known.

However, the liquid color-forming substance according to the present invention can be produced by dissolving a nonionic organic cyclic compound, typically a compound known as a liquid scintillation reagent, in an organic solvent and applying a voltage higher than the threshold voltage. These compounds generate anion radicals on the surface of the cathode, and these radicals absorb specific wavelengths in the visible light region, resulting in color development. Now as a liquid scintillation reagent 9,10-
The difference between the prior art and the present invention will be clarified by taking diphenylanthracene as an example. 9,10-diphenylanthracene produces outdoor luminescence under an alternating current chamber, but does not develop color.

On the other hand, 9,10-diphenylanthracene develops color under a DC electric field but does not emit light. In order to clarify this point, a coloring solution was prepared by dissolving 8 x 10-3 moles of 9,10-diphenylanthracene in IM's tetracylammonium perchlorate noacetonitrile solution, and a platinum electrode was placed in the solution. Various DC voltages are applied to the pair. An alternating current voltage was applied to examine the degree of color development.

The light transmission spectrum of the coloring liquid is shown in FIG. As is clear from this, when no voltage is applied, a spectrum is obtained in which the absorption is somewhat shifted towards the short wavelength side, and the entire spectrum is colored pale purple. When a rectangular wave of 50 Hz and 4.0 V was added to this, there was no change in the transmission spectrum, and therefore no color was developed. Similarly, there is almost no change even if a rectangular wave of 10 Hz and 5 Hz±4.0 V is applied. On the other hand, the distance between the electrodes is set to 0.5 ribs, and the DC electric field is 14.0V or -4.0V.
When applied, as shown in FIG. 1, it exhibits extreme absorption and develops a blue color.

That is, the display device of the present invention is based on a novel phenomenon in which a scintillation reagent develops color when a DC electric field is applied to it.
The display device of the present invention has no memory property, and can display various colors by selecting a color-producing substance.

The liquid scintillation reagent used in the present invention is commercially available as Dotite Reagent from Dojin Pharmaceutical Research Institute, for example, and one or more of the reagents shown in Table 1 can be used. Further, as the solvent for these coloring-causing substances, toluene, dioxane, acetone, dimethoxyethane, ethanol, dimethylformamide, hexane, anisole, paraxylene, etc. are used singly or as a mixed solvent. Further, as a supporting electrolyte, for example, tetraethylammonium perchlorate (TEAP), tetrabutylammonium perchlorate (TBAP), sodium perchlorate, lithium perchlorate, etc. may be added as a supporting electrolyte.

As a result of color development experiments using the above compounds,
The results shown in Table 2 were obtained.

In this experiment, each coloring solution shown in Table 2 was prepared (in the same table, the display of (1:1) indicating the mixing ratio of organic solvents indicates the weight ratio), and a pair of platinum electrodes was placed in the solution. A DC voltage of 4.0 V was applied between the electrodes, and color development between the cathodes was visually observed at room temperature. Table 2 Although the mechanism of color development according to the present invention is not clear, it is presumed as follows.

That is, on the surface of the cathode, the substance that causes coloration takes in electrons and generates anion radicals, which have a relatively long life and absorb light of a specific wavelength in the visible light region, so the electrode surface becomes colored. By doing. The electrolyte gives conductivity to the liquid and also provides 10-
2 to 10-3 mol/so is added. Even without adding an electrolyte, color can be developed by increasing the concentration of the color-causing substance to a certain extent, but the response is generally slow. The substance that causes color development in the present invention is dissolved in a stable organic solvent and is not ionized in the solution, so it is chemically stable when no voltage is applied. Since chemical changes are also very small, it is possible to obtain a long-life indicator with a repeat life of 2×1 pi or more at room temperature.

The higher the concentration of the coloring substance in the present invention, the faster the response speed of the rise, but the solubility in the solvent is usually not so great, so it is used at a concentration of 0.1 to 50%.

The voltage at which color development begins, that is, the voltage at which light transmittance decreases by 10%, is 3 to 4 V at room temperature when the distance between the electrodes is on the 0.5 side.
The color is saturated at 4 to 5V. Also, the power consumption is
Since it is as low as 1 to 5 hW/ when no supporting electrolyte is added, and 10 to 5 hW/ when a supporting electrolyte is added, it is suitable for application to display devices such as poppies and band devices. In addition,
The figure shows an example in which the liquid coloring material according to the present invention is used in a display device. In the figure, 1 is a transparent substrate, and a coating of tin oxide, indium oxide, or the like is formed as a transparent electrode 2 on the inner surface. Reference numeral 3 denotes a transparent or opaque base plate, and an electrode 4 made of Nesa, platinum, gold, or the like is formed on its inner surface.

5 is a sealing material for sealing this cell, and keeps the distance between the substrates 1 and 3 constant.

6 is a liquid coloring substance sealed inside the cell, and electrode 2
When a voltage is applied through 4 and 4, color develops.

As described above, according to the present invention, it is possible to realize a novel method for driving a display device that has a long life, provides good contrast, and produces color at low voltage and low power consumption.

In particular, as shown in Table 2, a variety of colors were obtained, such as reddish-purple, yellow, brown, dark blue, yellow-green, and blue.

As for the contrast, as shown in FIG. 1, the transmittance can be suppressed to about 85% when no voltage is applied, and to an average of several percent or less when DC 14.0 V is applied, and the difference is extremely large.

Furthermore, regarding the lifespan, in the display device of the present invention, the coloring substance is dissolved in a chemically stable solvent, and is not ionized when no voltage is applied, and there is no reaction with the supporting electrolyte, so the lifespan of the coloring liquid is limited. long.

[Brief explanation of drawings]

Figure 1 shows 9 when voltage is applied to compare the present invention and a conventional example.
, 10-diphenylanthracene. FIG. 2 is a sectional view showing a state in which the liquid coloring material according to the present invention is incorporated into a display device. 1...Transparent substrate, 2
...Transparent electrode, 3...Substrate, 4...Electrode, 5...
・Sealing material 6... Liquid coloring substance, 7... DC power supply. Figure 2 Figure 1

Claims (1)

[Claims] 1. 2,5-bis[5'-
Tertiary-butylbenzoxazolyl(2)']thiophene, 1,4bis[2-(5-phenyloxazolyl)
] Benzene, 1,4-bis(2-methylstyryl)benzene, 1,4-bis[2-(4-methyl-5-phenyloxazolyl)]benzene, 1,4-bis[2-(5- P
-tolyloxazole)]benzene, 2-(4'-tert-butylphenyl)-5-(4''-biphenyl)
-1,3,4-oxadiazole, 2,5-diphenylyloxazole, 9,10 diphenylanthracene, 1
, 6-diphenyl-1,3,5-hexatriene, P.
P'-diphenylstilbene, P-terphenyl, P-
At least one organic scintillation reagent such as quarterphenyl, 2(1-naphthyl)-5-phenyloxazole, an organic solvent for dissolving the scintillation reagent, and an electrolyte are used as a coloring liquid. In a method of driving a display device held between a pair of formed substrates, the color-forming substance is converted into anion radicals on the cathode surface by applying a DC voltage between the conductive layers, and the anion radicals are identified in a visible light region. A method for driving a display device characterized by generating color by absorbing light of a certain wavelength.