KR101871850B1 - Electrochromic material and Light-transmittance variable panel and display device including the same - Google Patents

Abstract

The present invention provides an electrochromic material having a transparency and a high light shielding degree represented by the following formulas, and a transmissive variable panel and a display device using the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electrochromic material, a light-transmittable variable panel and a display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a display device, and more particularly, to an electrochromic material having excellent transmittance and shielding degree, a light transmissive variable panel including the same, and a display device.

2. Description of the Related Art [0002] As an information society has developed, there has been a growing demand for a display device for displaying images. Recently, a liquid crystal display (LCD), a plasma display panel (PDP) Various flat display devices such as an organic light emitting diode (OLED) display device have been used.

Among these flat panel display devices, a liquid crystal display device and an organic light emitting diode display device are widely used.

The liquid crystal display device displays an image using the optical anisotropy and polarization properties of liquid crystal molecules. For example, in a liquid crystal display device, a liquid crystal layer including liquid crystal molecules is interposed between a pixel electrode and a common electrode, which are alternately arranged on a first substrate and a second substrate facing the first substrate.

On the other hand, the organic light emitting diode display device emits light by constituting an organic light emitting layer between the anode and the cathode. Electrons injected from the anode and electrons injected from the cathode are combined in the organic light emitting layer to form excitons, and excitons are emitted from the excited state to the ground state.

In recent years, there is an increasing interest in a transparent display device whose front surface is transparent and which transmits light. Such a transparent display device is being applied to a so-called smart window.

However, since the transparent display device does not have a black state, the contrast ratio is lowered and the visibility of the image is poor. To improve this, a method of using a shield plate on one surface of the display panel has been proposed.

For example, a liquid crystal panel, an electrophoretic panel or an electro-wetting panel which can change the transmittance is used as the shading plate.

1 is a schematic cross-sectional view of a conventional display device using an electrophoretic panel as a shading plate.

1, the display device 10 includes a transparent display panel 20 and a transmissivity-variable panel 30 disposed on one side of the transparent display panel 20. The transmissivity-

The transparent display panel 20 includes a plurality of pixels, and each pixel includes a display portion 22, a circuit portion 24, and a transparent portion 26. The display section 22 is driven by a voltage or a signal supplied through the circuit section 24 to display an image. The transparent display panel 20 may be a liquid crystal panel or a light emitting diode panel.

For example, when the transparent display panel 20 is a light emitting diode panel, it includes a first substrate 20a and a second substrate 20b facing each other, and between the first and second substrates 20a and 20b A display element (not shown) is formed.

In other words, the organic light emitting layer positioned between the first and second electrodes facing each other and the first and second electrodes are formed on the display portion 22. The circuit portion 24 is provided with a switching thin film transistor, a driving thin film transistor, May be formed.

When a gate signal is applied to the switching thin film transistor, the switching thin film transistor is turned on and a data signal is applied to the gate electrode of the driving thin film transistor and one electrode of the storage capacitor through the switching thin film transistor. The storage capacitor maintains the charge corresponding to the data signal for one frame to keep the amount of current flowing through the LED constant and to keep the gradation displayed by the LED constant.

When a voltage is applied to the first electrode of the light emitting diode through the driving thin film transistor, holes and electrons are injected from the first and second electrodes into the organic light emitting layer, respectively, and the light emitting diode emits light to display an image.

The transmissive variable panel 30 includes third and fourth substrates 32 and 34 facing each other, a transparent electrode 36 formed corresponding to the transparent portion 26 of the display panel 20, And an ink layer 38 positioned between the fourth substrates 32 and 34 and containing black electrophoretic particles 37. [ Although the third substrate 32 and the second substrate 20b are shown as one unit in FIG. 1, separate substrates may be attached to each other.

When a voltage is applied to the transparent electrode 36, the black electrophoretic particles 37 are gathered in the transparent electrode 36 to block the light transmission of the transparent portion 26. That is, the transmission mode and the cutoff mode are provided according to the application of the voltage of the transmissive variable panel 30.

Therefore, the light transmission in the transparent portion 26 can be selectively controlled.

However, in the case of the transmissivity-variable panel 10, which is an electrophoretic panel, it is difficult to uniformly disperse the black electrophoretic particles 37 and the ink layer 38 in a fluid state is leaked.

In addition, when the liquid crystal panel is used as a transmissive variable panel, the transmissivity in the transmissive mode is low, so that the brightness of the display device is lowered and the light-shielding efficiency is not good.

In addition, when the electrowetting panel is used as a light transmittance variable panel, it is difficult to manufacture a panel using black oil, black salt, pigment precipitation, fluid leakage, and the like.

An object of the present invention is to provide an electrochromic material and a variable transmittance panel having a high transmittance and an excellent light shielding property.

In order to solve the above problems, the present invention provides a electrochromic material represented by the following formula and R is selected from substituted or unsubstituted alkyl groups, substituted or unsubstituted aromatic groups.

The electrochromic material of the present invention is any one of the following compounds.

According to another aspect of the present invention, there is provided a plasma display panel comprising first and second substrates facing each other, a first transparent electrode positioned on the first substrate, a second transparent electrode positioned on the second substrate, An electrochromic particle layer disposed between the transparent electrode and the second transparent electrode and including electrochromic particles of a core and a shell; and an electrolyte layer positioned between the second transparent electrode and the electrochromic particle layer, A transmissive variable panel comprising an electrochromic material is provided.

In the variable transmissivity panel of the present invention, the electrolyte layer is a solid electrolyte containing a lithium salt.

In yet another aspect, the present invention provides a light-emitting device comprising: the transmissivity-variable panel described above; And a display panel located on one side of the transmittance variable panel and including a display portion and a transparent portion.

The electrochromic material of the present invention is composed of a compound of a viologen derivative core in which a phenoxyphenyl and a phosphoric acid group are bonded to each other, and thus has excellent transparency and light shielding efficiency.

In addition, it is composed of a core and a shell of an electrochromic material and provides electrochromic particles, and a transmissive panel including the electrochromic particles has excellent transmittance and light shielding efficiency. Further, since the core and the shell are chemically bonded, the driving stability is improved.

Since such electrochromic particles are spherical nanoparticles, the specific surface area increases. Therefore, the light-shielding efficiency of the variable transmissivity panel is improved.

Further, since the film can be formed using a solid electrolyte, problems such as fluid leakage in the conventional transmittance variable panel can be prevented.

Further, the visibility and contrast ratio of the display device including the transmissivity-variable panel of the present invention is increased.

1 is a schematic cross-sectional view of a conventional display device using an electrophoretic panel as a shading plate.
2 is a schematic diagram of electrochromic particles according to an embodiment of the present invention.
3 is an NMR graph of the electrochromic particles according to an embodiment of the present invention.
4 is a schematic cross-sectional view of a transmissivity-variable panel according to an embodiment of the present invention.
5 is a schematic cross-sectional view of a display device including a transmissivity-variable panel according to an embodiment of the present invention.
6 is a schematic cross-sectional view of the display panel of Fig.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings.

2 is a schematic diagram of electrochromic particles according to an embodiment of the present invention.

2, the electrochromic particles 100 according to an exemplary embodiment of the present invention include a core 110 and a shell 120 surrounding the core 110. The core 110 includes a core 110 and a shell 120. [

The core 110 may be made of a dielectric material. For example, the core 110 may be made of indium-tin-oxide (ITO) or titanium oxide (TiO2).

The shell 120 surrounds the core 110 and is made of an electrochromic material represented by the following Chemical Formula 1.

[Chemical Formula 1]

In formula (1), R may be selected from substituted or unsubstituted alkyl groups, substituted or unsubstituted aromatic groups.

For example, R may be any one of phenoxyphenyl, benzyl, hexyl, naphthyl, and phenylbenzyl.

That is, the electrochromic material of the present invention comprises a first viologen substituted with phenoxyphenyl and a second viologen substituted with alkylphophonate, a substituted or unsubstituted An alkyl group, a substituted or unsubstituted aromatic group (for example, phenoxyphenyl, phenyl, hexyl, naphthyl or phenylbenzyl) is bonded to a benzene ring. The electrochromic particles having such a structure that the electrochromic material covers the core have excellent light transmission and light shielding properties. In particular, since the black is realized in the shading mode, the shading ratio is improved.

Further, since the phosphonate group of the electrochromic material is chemically bonded to the core, the driving stability is improved.

For example, the electrochromic material of formula (1) may be selected from materials of the following formulas (2-1) to (2-5).

[Formula 2-1]

[Formula 2-2]

[Formula 2-3]

[Chemical Formula 2-4]

[Chemical Formula 2-5]

The electrochromic particles having such a structure that the electrochromic material surrounds the core have a good transparency, so that the light transmittance increases when the electric field is not applied. In addition, since the electrochromic particles of the present invention are spherical nanoparticles of a core-shell structure, the specific surface area of the electrochromic particles is increased as compared with the case of a plate form. Therefore, when an electric field is applied to the electrochromic particles, the light blocking efficiency increases.

Further, since the electrochromic material is chemically bonded, the driving stability is improved.

Hereinafter, synthesis examples of the electrochromic materials according to the present invention will be described.

1. First Synthesis Example (Synthesis of Electrochromic Material of Formula 2-1)

(0.1 mol) of bipyridine and 24.5 g (0.1 mol) of bromoethylphosphonate in a 1: 1 mixture of methanol and water were added to a three-necked flask equipped with a nitrogen atmosphere, followed by addition of 12 Lt; / RTI > The solvent was distilled and purified to give a white solid.

40.0 grams of the above white solid and 35.6 grams (0.1 mole) of 1,3,5-tribromobenzene were placed in a solvent mixture of ethanol and toluene in an amount of 8: 2, followed by reaction for 3 days. The reaction product was purified to give a pale yellow substance. 70 grams of the above yellow substance was placed in 7.1 grams (0.1 mole) of 3oxo-3 (4-phenoxyphenyl) propionic acid methyl ester, 31.2 grams (0.2 mole) of bipyridine and 300 grams of methanol, Lt; / RTI > The reaction product was first treated with an aqueous solution of HCl (38% by weight), and impurities were removed by recrystallization to synthesize the electrochromic material of Formula (2-1).

FIG. 3 shows an NMR graph of synthesized Formula 2-1 electrochromic material.

2. Synthesis Example 2 (Synthesis of electrochromic material of Formula 2-2)

Except that 0.1 mol of 3-oxo-3 (4-phenoxyphenyl) propionic acid methyl ester and 0.1 mol of benzyl bromide were used instead of 3-oxo-3 (4-phenoxyphenyl) propionic acid methyl ester in the first synthetic example 1 The electrochromic material of formula (2-2) was synthesized in the same manner as in the synthesis example.

3. Third Synthesis Example (Synthesis of Electrochromic Material of Formula 2-3)

Except that 0.1 mol of 3-oxo-3 (4-phenoxyphenyl) propionic acid methyl ester and 0.1 mol of bromohexane were added instead of 3-oxo-3 (4-phenoxyphenyl) propionic acid methyl ester in the first synthetic example The electrochromic material of Formula 2-3 was synthesized in the same manner as in the first synthesis example.

4. Synthesis Example 4 (Synthesis of electrochromic material of Formula 2-4)

In the first synthetic example, 0.1 mol of 3-oxo-3 (4-phenoxyphenyl) propionic acid methyl ester and 0.1 mol of 2-bromomethyl-naphthalene were used instead of 3-oxo- The electrochromic material of Formula 2-4 was synthesized in the same manner as in the first synthesis example.

5. Synthesis Example 5 (Synthesis of electrochromic material of Formula 2-5)

In the first synthesis example, 0.1 mol of 3-oxo-3 (4-phenoxyphenyl) propionic acid methyl ester and 0.1 mol of 3-phenyl-benzyl bromide were used instead of 3-oxo- The electrochromic material of Formula 2-5 was synthesized in the same manner as in the first synthesis example.

4 is a schematic cross-sectional view of a transmissivity-variable panel according to an embodiment of the present invention.

4, the variable transmissivity panel 200 includes first and second substrates 210 and 220 facing each other, first and second substrates 210 and 220, A first transparent electrode 240 positioned between the first substrate 210 and the electrochromic layer 240 and an electrochromic layer 240 disposed between the electrochromic particles 100 and the electrolyte 130, And a second transparent electrode 250 positioned between the second substrate 220 and the electrochromic layer 240. [

Each of the first substrate 210 and the second substrate 220 may be made of glass or plastic. For example, each of the first substrate 210 and the second substrate 220 may be formed of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

Each of the first transparent electrode 230 and the second transparent electrode 250 is made of a transparent conductive material. For example, each of the first transparent electrode 230 and the second transparent electrode 250 may be formed of indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) ≪ / RTI > The variable transmissivity panel of the present invention is formed of a transparent conductive material because the transmissivity must be high in the transmissive mode. Alternatively, when the transmissive panel is formed of a low resistance metal material such as aluminum, the transmissive panel may have a small thickness.

The electrochromic layer 240 and the electrolyte layer 130 are disposed between the first and second substrates 210 and 220, that is, between the first and second transparent electrodes 230 and 250, .

Referring to FIG. 2, the electrochromic particles 100 have a structure of a core 110 and a shell 120, and the shell 120 is composed of a electrochromic material represented by the following formula (1).

That is, in the electrochromic particle 100, the shell 120 surrounding the core 110 is divided into a first viologen substituted with phenoxyphenyl and a second viologen substituted with alkylphophonate. A third viologen substituted with a viologen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic group (e.g., phenoxyphenyl, phenyl, hexyl, naphthyl or phenylbenzyl) And the permeability of the electrochromic particles 100 is increased accordingly.

Also, when the voltage is applied, the shell 120 made of the electrochromic material is discolored and the light blocking efficiency is increased. Since the electrochromic material of the present invention changes to black by applying a voltage, it has excellent light shielding efficiency without mixing with other materials.

The electrolyte layer 130 may be a solid electrolyte including an ionic salt, an ionic conductor, a plasticizer, and a polymeric binder. For example, the ionic salt may be a lithium (Li) salt.

Although not shown, a counter layer may be formed between the electrolyte layer 130 and the second transparent electrode 250 to facilitate the oxidation-reduction reaction in the electrochromic layer 240. For example, the counter electrode may be made of any one of PEDOT, ferrocene, triphenylamine, diphenylamine, phenothiazine, and phenoxazine-based polymers.

The variable transmissivity panel 200 having such a structure has a transmitting state or a shielding state by the application of a voltage.

That is, since the electrochromic particles 100 are transparent in a state where no voltage is applied to the first and second transparent electrodes 230 and 250, the transmittance variable panel 200 transmits light. On the other hand, when a voltage is applied to the first and second transparent electrodes 230 and 250, the shell 120 made of the electrochromic material of Formula 1 is discolored, and the transmissive panel 200 blocks light.

In other words, the transmissivity-variable panel 200 of the present invention is different in transmittance depending on whether a voltage is applied or not, and can be applied to a transparent display device as described later, thereby improving visibility and contrast ratio of the transparent display device.

[Synthesis of electrochromic particles]

2.0 g of each of the electrochromic materials of formulas (2-1) to (2-5) synthesized through the first to fifth synthetic examples were dissolved in 20 g of methanol, and the mixture was stirred at 50 ° C for 3 hours using ultrasonic waves A clear solution was obtained. 50 g of ITO powder (particle size > 15 nm, solvay), 0.5 g of 2,4 pentanadione and 0.05 g of BYK160 were added to 120 g of isopropyl alcohol, and stirred for 1 hour. 50 g of the transparent solution and 200 g of 0.1 mm zirconia beads were added and sealed. The electrochromic particle solution was prepared by dispersing for 24 hours using a ball mill moving at 600 rpm.

[Production of solid electrolyte]

300 g of acetonitrile, 10.0 g of polyethylene oxide (molecular weight 600 K) and 15.0 g of siloxane having 0.8 mol of ethylene oxide were added to a flask equipped with a stirrer, and the mixture was stirred for 60 minutes. 1.77 grams of LiTFSi, 0.5 grams of S104 (Air product) as an additive and 0.05 grams of OXE01 (BASF) as a photoinitiator were added and stirred at a temperature of 50 degrees for 6 hours to prepare a transparent polymer electrolyte solution. The thus-prepared solid electrolyte was coated on the electrode separated by a gap of 1 mm, and then the solvent was dried. Impedance was measured by irradiating with UV of 0.1 J / cm 2, and as a result, the ion conductivity of the solid electrolyte layer was 5.4 * 10 ^-5 S / cm.

[Production of counter electrode]

30 grams of vinyl ferrocene and 300 grams of chlorobenzene were placed in a flask equipped with a stirrer and dissolved by stirring. After the temperature was raised to 60 ° C, an initiator for radical polymerization was added at a rate of 0.05 g / min and reacted for 23 hours to obtain a vinylpyrrole polymer having a molecular weight of 8,000. The synthesized polymer was dissolved in dichlorobenzene and spin coated on the substrate at 1000 rpm to prepare a counter electrode.

[Preparation of Transmittance Variable Panel]

[Experimental Example 1]

The electrochromic particle solution prepared using the electrochromic material synthesized through the first synthesis example was coated on an ITO PET film having a sheet resistance of 40? / Sq to a final thickness of 2 microns and then dried at 80 占 폚 for 30 minutes Thereby forming an electrochromic particle layer.

A solid electrolyte was coated on another ITO PET film having the same sheet resistance to form a solid electrolyte layer having a thickness of about 100 microns. Thereafter, the substrate was dried at a temperature of 100 degrees for 3 minutes, and irradiated with UV light of 0.1 J / cm < 2 > to cure the solid electrolyte layer.

The PET film on which the electrochromic particle layer was formed and the solid electrolyte layer were joined together with the film on which the counter electrode was formed at a temperature of 40 degrees to prepare a variable transmittance panel.

The transmittance and shading rate (on / off) of on (black) / off (transparent) were measured using DMS803 (Konica Minolta Spectrophotometer) by applying a voltage of +1.3 and -1.3 volts to the variable transmittance panel and aging 50 times at intervals of 10 seconds. And color coordinates were measured.

[Experimental Example 2]

Using the electrochromic material synthesized through the second synthesis example, a transmittance variable panel was prepared in the same manner as in Experimental Example 1, and transmittance, shading ratio and color coordinates were measured.

[Experimental Example 3]

Using the electrochromic materials synthesized in the third synthesis example, a transmittance variable panel was prepared in the same manner as in Experimental Example 1, and transmittance, shading ratio and color coordinates were measured.

[Experimental Example 4]

Using the electrochromic material synthesized through the fourth synthetic example, a transmittance variable panel was prepared in the same manner as in Experimental Example 1, and transmittance, shading ratio and color coordinates were measured.

[Experimental Example 5]

Using the electrochromic materials synthesized in the fifth synthesis example, a transmittance variable panel was prepared in the same manner as in Experimental Example 1, and transmittance, shading ratio and color coordinates were measured.

[Comparative Example]

Using the electrochromic material of Chemical Formula 3, a transmittance variable panel was prepared in the same manner as Experimental Example 1, and transmittance, shading ratio and color coordinates were measured.

(3)

The measurement results of Experimental Examples 1 to 5 and Comparative Examples are shown in Table 1 below.

As shown in Table 1, when the electrochromic material of the present invention is used, it has a high transmittance and a high degree of light shielding.

That is, a first viologen substituted with phenoxyphenyl and a second viologen substituted with alkylphosphonate, a substituted or unsubstituted alkyl group, a substituted or unsubstituted A core-shell comprising a electrochromic material of formula (1) having a structure in which a third viologen substituted with an aromatic group (for example, phenoxyphenyl, phenyl, hexyl, naphthyl or phenylbenzyl) By using the electrochromic particles of the structure, it has excellent light transmission and light shielding characteristics.

In particular, the light transmission and light shielding properties are greatly improved by the phenoxyphenyl substituent.

Compared with the comparative example having no phenoxyphenyl substituent, the shading ratio is particularly improved. That is, since the electrochromic material of the comparative example having no phenoxyphenyl substituent does not realize black in the light shielding mode, the light shielding rate is lowered.

Further, in the electrochromic material of the present invention, since the phosphonate group is chemically bonded to the core, the driving stability is improved.

5 is a schematic cross-sectional view of a display device including a transmissivity-variable panel according to an embodiment of the present invention.

5, the display device 300 includes a transparent display panel 310 and a transmissivity-variable panel 200 disposed on one side of the transparent display panel 310. The transmissivity-

The transparent display panel 310 includes a plurality of pixels, and each pixel includes a display portion 312, a circuit portion 314, and a transparent portion 316. The display unit 312 is driven by a voltage or a signal supplied through the circuit unit 314 to display an image. The transparent display panel 310 may be a liquid crystal panel or a light emitting diode panel.

The case where the transparent display panel 310 is a light emitting diode panel will be briefly described.

6, which is a schematic cross-sectional view of the display panel of FIG. 5, the transparent display panel 310 includes a third substrate 401 and a fourth substrate 402 facing each other, (Not shown) is formed between the light emitting diodes 401 and 402, and the display element is a light emitting diode D.

Each of the third substrate 401 and the second substrate 402 may be made of glass or plastic. For example, each of the third substrate 401 and the second substrate 402 may be formed of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

A gate wiring (not shown) and a data wiring (not shown) are formed on the third substrate 401 to define a pixel region P and are parallel to a gate wiring (not shown) or a data wiring (not shown) (Not shown) is formed. The display portion 312, the driver 314, and the transparent portion 316 are defined in each pixel region P. [

A switching thin film transistor (not shown) is formed in each pixel region P at the intersection of the gate wiring (not shown) and the data wiring (not shown).

Also, a driving thin film transistor DTr is formed, which is connected to a switching thin film transistor (not shown) and a power supply wiring (not shown).

The driving thin film transistor DTr includes a semiconductor layer 410, a gate electrode 420, and source and drain electrodes 431 and 433. The switching thin film transistor may have a structure similar to that of the driving transistor DTr.

The semiconductor layer 410 includes source and drain regions SR and DR located on both sides of the channel region CR and the channel region CR. The semiconductor layer 410 may be formed of polycrystalline silicon.

A buffer layer (not shown) may be formed between the semiconductor layer 410 and the third substrate 401.

On the semiconductor layer 410, a gate insulating film 415 is formed. The gate insulating film 415 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

On the gate insulating film 415, a gate electrode 420 is formed corresponding to the channel region CR. The gate electrode 420 may be made of a low-resistance metal material such as copper or aluminum.

On the gate electrode 420, an interlayer insulating film 425 is formed. A semiconductor contact hole 435 may be formed in the interlayer insulating film 225 and the gate insulating film 415 to expose the source region SR and the drain region DR, respectively. The interlayer insulating film 425 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

On the interlayer insulating film 425, the source electrode and the drain electrode 431 and 433 are formed. The source and drain electrodes 231 and 233 are in contact with the source and drain regions SR and DR of the semiconductor layer 410 through the corresponding semiconductor contact holes 235, respectively.

A protective layer 440 may be formed on the source and drain electrodes 431 and 433. The protective layer 440 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride or an organic insulating material such as photoacryl. A drain contact hole 441 exposing the drain electrode 433 is formed in the protection layer 440.

The light emitting diode D is located on the protective layer 440 and is electrically connected to the driving thin film transistor DTr through the drain contact hole 441.

In the above-mentioned example, a case where a transistor using a semiconductor layer 410 made of crystalline silicon is formed is taken as an example. As another example, a transistor having an inverted staggered structure using amorphous silicon as a semiconductor layer may be used. As another example, an oxide transistor using an oxide semiconductor may be used.

Although not shown, a storage capacitor is formed in each pixel region P.

The light emitting diode D may include first and second electrodes 451 and 453 and an organic light emitting layer 452 formed between the first and second electrodes 451 and 453.

Here, the first and second electrodes 451 and 453 are configured to have a transparent characteristic. In this regard, the first and second electrodes 251 and 253 may be formed of a transparent conductive material. For example, one of oxide-based transparent conductive materials such as ITO, IZO, GZO, and IGZO may be used. At this time, one of the first and second electrodes 451 and 453 is an anode and the other is a cathode. The positive electrode is made of a material having a relatively large work function value, and the negative electrode is made of a material having a relatively low work function value.

The first electrode 451 is connected to the drain electrode 433 of the driving thin film transistor DTr through the drain contact hole 441 and is patterned in units of the pixel region P. [ The second electrode 453 is integrally formed corresponding to the entire pixel region P of the display panel 310 (FIG. 5).

On the other hand, on the first electrode 451, a bank 460 having an opening per pixel region P may be formed. The bank 460 serves to distinguish adjacent pixel regions P from each other.

An organic light emitting layer 452 is formed for each pixel region P corresponding to the opening of the bank 460. [ The organic light emitting layer 452 functions to emit light by the combination of holes and electrons supplied from the first and second electrodes 451 and 453.

The organic light emitting layer 452 may include a light emitting material layer that substantially emits light. On the other hand, the organic light emitting layer 452 may have a multi-layer structure to enhance the light emitting efficiency. For example, the organic light emitting layer may further include a hole injecting layer, a hole transporting layer, an electron injecting layer, and an electron transporting layer in addition to the light emitting material layer.

The light emitting diode D having the above-described configuration generates light of a corresponding brightness according to a signal applied to the gate electrode 420 of the driving thin film transistor DTr.

The fourth substrate 402 is an encapsulation substrate and covers the driving thin film transistor DTr. Although not shown, a barrier layer may be formed between the fourth substrate 402 and the driving thin film transistor DTr to prevent penetration of moisture or the like.

6, the region where the driving element such as the driving thin film transistor DTr is formed corresponds to the driving portion (314 in FIG. 5), and the region where the light emitting diode D is formed corresponds to the display portion (312 in FIG. 5). On the other hand, light is transmitted through the transparent portion (316 in Fig. 5) without forming the driving element and the display element. Further, the display portion 312 and the driving portion 314 may be regions overlapping each other.

5, the variable transmissivity panel 200 includes first and second substrates 210 and 220 facing each other, and an electrochromic particle (not shown) disposed between the first and second substrates 210 and 220 A first transparent electrode 240 positioned between the first substrate 210 and the electrochromic layer 240 and a second transparent electrode 240 interposed between the first substrate 210 and the electrochromic layer 240. The electrochromic layer 240 includes the first substrate 210 and the electrolyte layer 130, And the second transparent electrode 250 positioned between the electrochromic layer 240 and the electrochromic layer 240. The transmittance variable panel 200 further includes a counter layer positioned between the electrolyte layer 130 and the second transparent electrode 250 and for facilitating the oxidation-reduction reaction in the electrochromic layer 240 can do.

Each of the first substrate 210 and the second substrate 220 may be made of glass or plastic. For example, each of the first substrate 210 and the second substrate 220 may be formed of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

5 and 6, the first substrate 210 of the variable transmissivity panel 200 and the fourth substrate 402 of the display panel 310 are shown to have the same configuration, but different substrates are used, So that the transmissivity variable panel 200 and the display panel 310 can be stacked.

Each of the first transparent electrode 230 and the second transparent electrode 250 is made of a transparent conductive material.

The electrochromic layer 240 and the electrolyte layer 130 are disposed between the first and second substrates 210 and 220, that is, between the first and second transparent electrodes 230 and 250, .

The electrochromic particles 100 have a structure of a core (110 in FIG. 2) and a shell (120 in FIG. 2), and the shell 120 is made of a electrochromic material represented by the formula (1).

That is, in the electrochromic particle 100, the shell 120 surrounding the core 110 is divided into a first viologen substituted with phenoxyphenyl and a second viologen substituted with alkylphophonate. A third viologen substituted with a viologen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic group (e.g., phenoxyphenyl, phenyl, hexyl, naphthyl or phenylbenzyl) And the permeability of the electrochromic particles 100 is increased accordingly.

Also, when the voltage is applied, the shell 120 made of the electrochromic material is discolored and the light blocking efficiency is increased. Since the electrochromic material of the present invention changes to black by applying a voltage, it has excellent light shielding efficiency without mixing with other materials.

The electrolyte layer 130 may be a solid electrolyte including an ionic salt, an ionic conductor, a plasticizer, and a polymeric binder. For example, the ionic salt may be a lithium (Li) salt.

The variable transmissivity panel 200 having such a structure has a transmitting state or a shielding state by the application of a voltage.

That is, since the electrochromic particles 100 are transparent in a state where no voltage is applied to the first and second transparent electrodes 230 and 250, the transmittance variable panel 200 transmits light. On the other hand, when a voltage is applied to the first and second transparent electrodes 230 and 250, the shell 120 made of the electrochromic material of Formula 1 is discolored, and the transmissive panel 200 blocks light.

In other words, since the shell (120 in Fig. 2) of the electrochromic particles 100 has a transparent state in a state where no voltage is applied to the first and second transparent electrodes 230 and 250, the transmittance variable panel 200 Becomes a transmissive mode, and the light of the transparent portion 316 is transmitted therethrough.

However, when a voltage is applied to the first and second transparent electrodes 230 and 250, the shell (120 in Fig. 2) of the electrochromic particles 100 changes to black, so that the transmittance variable panel 200 is in the cutoff mode Thereby blocking the light.

Therefore, the display device 300 of the present invention including the variable transmissivity panel 200 is used as a so-called transparent display device.

As described above, the electrochromic material represented by Formula (1) is obtained by reacting a first viologen substituted with phenoxyphenyl, a second viologen substituted with alkylphophonate, Or a structure in which a third viologen substituted with an unsubstituted alkyl group, a substituted or unsubstituted aromatic group (for example, phenoxyphenyl, phenyl, hexyl, naphthyl or phenylbenzyl) is bonded to the benzene ring , And the electrochromic layer 240 using the same has high transmittance and excellent light shielding efficiency. Therefore, it is possible to provide a transparent display device with improved visibility and contrast ratio.

Further, since the shell and the core have a chemical bonding state, the driving stability is improved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that

100: electrochromic particles 110: core
120: Shell 130: Electrolyte layer
200: Transmittance variable panel 210, 220, 401, 402:
230, 250: transparent electrode 300: display device
310: Display panel

Claims (5)

Wherein R is selected from the group consisting of an unsubstituted alkyl group, an alkyl group substituted with a C6 to C12 aromatic group, and an aromatic group substituted with a phenoxy group.

The method according to claim 1,
Wherein the electrochromic material is any one of the following compounds.

A first substrate and a second substrate facing each other;
A first transparent electrode disposed on the first substrate;
A second transparent electrode disposed on the second substrate;
An electrochromic particle layer disposed between the first transparent electrode and the second transparent electrode and including electrochromic particles of a core and a shell;
And an electrolyte layer positioned between the second transparent electrode and the electrochromic particle layer,
Wherein the shell comprises the electrochromic material of claim 1 or 2.
The method of claim 3,
Wherein the electrolyte layer is a solid electrolyte comprising a lithium salt.
A transmissive variable panel according to claim 3;
The display panel including a display portion and a transparent portion, the display panel being positioned on one side of the transmissivity-
.

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