CN100463246C - Organic Electroluminescent Display Elements - Google Patents

Abstract

An organic electroluminescent display element is mainly composed of a substrate, a first electrode layer, a second electrode layer, an organic functional layer and an electrochromic medium layer. The first electrode layer is arranged on the substrate, the second electrode layer is arranged on the first electrode layer, and the organic functional layer and the electrochromic medium layer are arranged between the first electrode layer and the second electrode layer. The electrochromic medium layer is used as a selective light valve to improve the reflection phenomenon of external light, so as to further increase the contrast of the organic electroluminescent display element.

Description

Organic Electroluminescent Display Elements

technical field

The present invention relates to an organic electroluminescence display element (Organic Electroluminescence, OEL), and in particular to an organic electroluminescence display element with a selective light valve.

Background technique

The communication industry has become the mainstream industry today, especially portable communication products are the focus of development, and the flat panel display is the communication interface between human and machine, so it is particularly important. The technologies currently applied to flat panel displays mainly include the following: plasma display (Plasma Display Panel, PDP), liquid crystal display (Liquid Crystal Display, LCD), inorganic electroluminescent display (Inorganic Electro-luminescent Display), light emitting diode (Light Emitting Diode, LED), vacuum fluorescent display (Vacuum Fluorescent Display) and field emission display (Field Emission Display, FED), etc. However, compared with other flat-panel display technologies, organic electroluminescent elements (OEL) have the advantages of self-luminescence, no viewing angle dependence, power saving, simple manufacturing process, low cost, low operating temperature range, high response speed and full color. It has great application potential and is expected to become the next generation of flat-panel displays.

Organic electroluminescent elements are elements that use the self-luminous properties of organic functional materials to achieve display effects. They can be divided into small molecule organic light-emitting elements (small molecule OLEDs, SM-OLED) and polymer light-emitting device (polymer light-emitting device, PLED) two categories. Its light-emitting structure is mainly composed of a pair of electrodes and an organic functional material layer. When the current passes between the pair of electrodes, electrons and holes are combined in the organic functional material layer to generate excitons, which can make the organic functional material layer produce light emission mechanisms of different colors according to the characteristics of its materials. This is the light emitting principle of the organic electroluminescent element.

For any display element, the brightness ratio of full brightness to full darkness is a major factor in determining its recognition. This brightness ratio is generally called the contrast ratio (Contrast Ratio, CR). The better the degree, and the definition of contrast is shown in the following formula (1):

$\mathrm{<span\; class="notranslate">\; CR</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; sub</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; on</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; amb</span>}}}{{\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; sub</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; off</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; amb</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, L _{sub, on} is the brightness when the pixel (pixel) is lit, L _{sub, off} is the brightness when the pixel is not lit, and _Ramb is the brightness reflected by the external light entering the display element, assuming that the pixel The brightness when it is lit is 100 nits, and the brightness when it is not lit is 1 nits, then the relationship between the brightness of the external light entering the display element and the reflected brightness of the display element and the contrast of the display element can be calculated according to formula (1). In other words, it can be known from formula (1) that when the external light is stronger, the contrast is smaller, which means that the recognition is worse. , when the external light is very weak, the contrast increases. At this time, the brightness of the pixels to be lit can be appropriately dimmed to reduce power consumption and reduce the glare.

FIG. 1 is a schematic diagram of a known organic electroluminescence display element. Please refer to FIG. 1 , the conventional organic electroluminescence display device is mainly composed of a substrate 100 , a transparent electrode layer 102 , an organic functional layer 104 and a metal electrode layer 106 . Wherein, the substrate 100 usually uses a glass substrate; the material of the transparent electrode layer 102 is usually a transparent conductive material such as indium tin oxide; , hole transport layer, organic electroluminescence layer, electron transport layer and electron injection layer and other multi-layer thin films; and the material of the metal electrode layer 106 is usually aluminum, calcium or magnesium-silver alloy. When the current passes between the transparent electrode layer 102 and the metal electrode layer 106, electrons and holes are combined in the organic functional layer 104 to generate excitons, which can make the organic functional layer 104 produce different colors according to the characteristics of its materials. Lighting mechanism. In other words, the organic electroluminescent display element is driven by current, and converts electrical energy into light energy to achieve the purpose of display.

As shown in FIG. 1, the refractive index _n1 of the organic functional layer 104 is very close to the refractive index _n2 of the transparent anode layer 102, and the refractive index _n1 of the organic functional layer 104 is greater than the refractive index _n3 of the transparent substrate 100, for example, where n ₁ is about 1.7, n ₂ is about 1.8 to 2.0, and n ₃ is about 1.5, and n ₃ is larger than the refractive index of the outside air ("1).

Based on the above, the light in the organic electroluminescent display element is generated by the organic functional layer 104. Although the direction of travel of the generated light is arbitrary, the metal electrode layer 106 can be regarded as a reflective layer, so the light can only transmitted toward the direction of the transparent substrate 100 . However, the light emitted toward the transparent substrate 100 is usually affected by the external light, so that its visibility is not as expected. Wherein, when external light enters the organic electroluminescent display element, it will mainly be reflected at the interface between the air and the transparent substrate 100, the interface between the transparent substrate 100 and the transparent electrode layer 102, and the interface between the organic functional layer 104 and the metal electrode layer 106, and then transmitted toward the direction of the transparent substrate 100 .

As mentioned above, the reflected light _W1 at the interface between the air and the transparent substrate 100 accounts for about 4%, the reflected light _W2 at the interface between the transparent substrate 100 and the transparent electrode layer 102 accounts for about 0.8%, and the organic functional layer 104 and the metal electrode layer 106 The reflected light W ₃ of the interface exceeds 90%. It can be seen that most of the reflected light is generated by the reflection of the metal electrode layer 106 . In other words, the interface between the organic functional layer 104 and the metal electrode layer 106 is the main source of reflected light. As a result, when the organic electroluminescent display element is used outdoors, it is easy to be reflected by external strong light, and the display effect is recognizable. Bad phenomenon. Therefore, how to reduce the external strong light entering the reflective interface between the organic functional layer 104 and the metal electrode layer 106 has become the most important issue to be solved to improve the visibility of the organic electroluminescent display element under strong light.

The known technology usually solves the above-mentioned reflective problem by attaching a polarizer, or adding a photometric sensor and a contrast adjustment device. However, these two methods have the following disadvantages:

1. Attaching a polarizer is a comprehensive shading method. Although it can reduce the reflection of non-lit pixels, it also reduces the brightness of lit pixels, so it cannot produce sufficient recognition effect in sunlight.

2. The cost of adding a photometric sensor and a contrast adjustment device to adjust the contrast of the display according to different ambient light levels is too high.

Contents of the invention

The object of the present invention is to propose an organic electroluminescent display element with a selective light valve, the selective light valve of which can produce light-shielding and light-transmitting effects for the non-lit pixel area and the lighted pixel area respectively, so as to Effectively improve the contrast under strong light, thereby increasing the recognition effect of display components.

In order to achieve the above object, the present invention proposes an organic electroluminescence display element, comprising at least:

a substrate;

a first electrode layer configured on the substrate;

a second electrode layer configured on the first electrode layer;

an organic functional layer disposed between the first electrode layer and the second electrode layer; and

At least one electrochromic medium layer is arranged between the first electrode layer and the second electrode layer.

Wherein the organic functional layer is disposed on the first electrode layer, and the electrochromic medium layer is disposed between the organic functional layer and the second electrode layer.

Wherein the electrochromic medium layer is disposed on the first electrode layer, and the organic functional layer is disposed between the electrochromic medium layer and the second electrode layer.

Wherein the organic functional layer at least includes an organic electroluminescence layer.

Wherein the organic functional layer further includes a hole injection layer, and the hole injection layer is disposed between the first electrode layer and the organic electroluminescence layer.

Wherein the organic functional layer further includes a hole transport layer, and the hole transport layer is disposed between the hole injection layer and the organic electroluminescent layer.

Wherein the organic functional layer further includes an electron injection layer, and the electron injection layer is disposed between the second electrode layer and the organic electroluminescence layer.

Wherein the organic functional layer further includes an electron transport layer, and the electron transport layer is disposed between the electron injection layer and the electromechanical luminescence layer.

Wherein the electrochromic medium layer is disposed between any two layers of the hole injection layer, the hole transport layer, the organic electroluminescent layer, the electron transport layer and the electron injection layer.

The material of the electrochromic medium layer is selected from transition metal oxides, Prussian compounds, Viologens, conductive polymers, transition enzyme lanthanide coordination complexes and metal polymers (Transition meal and lanthanide coordination complexes) and metallopolymers) and metal phthalocyanine fuels (Metal phthalocyanines) at least one of them.

Wherein the transition metal oxide is selected from at least one of WO ₃ , MoO ₃ , V ₂ O ₅ and Nb ₂ O ₅ .

Wherein the Prussian compound is selected from (Fe ^III Fe ^II (CN) ₆ ) ^- , (Fe ^III Fe ^III (CN) ₆ ) and (Fe ^II Fe ^II (CN) ₆ ) ^{2 -} at least one of them.

Wherein the viologens include 1'-disubstituted-4 (1,1'-Disstituted-4), 4'-bipyridinium salts (4'-bipyridinium salts).

Wherein the conductive polymer is selected from at least one of polypyrrole, polythiophene, polyaniline and polyethylenedioxythiophene (PEDOT).

Wherein the transition enzyme lanthanide coordination complexes and metal polymers (Transition meal andlanthanide coordination complexes and metallopolymers) are selected from at least one of hydrogenase (mealhydride) and nitrosyl oxygen molybdenum complexes (nitrosyl and oxo molybdenum complexes).

The present invention further proposes an organic electroluminescence display element, comprising at least:

A first substrate having a display surface;

a first electrode layer configured on the first substrate, wherein the display surface and the first electrode layer are respectively located on opposite sides of the first substrate;

a second electrode layer configured on the first electrode layer;

an organic functional layer disposed between the first electrode layer and the second electrode layer; and

A selective light valve is disposed on the display surface.

Wherein the selective light valve comprises a liquid crystal light valve.

Wherein the liquid crystal light valve includes a second substrate, a third substrate and a liquid crystal layer, the third substrate is arranged on the display surface, and the liquid crystal layer is arranged between the second substrate and the third substrate.

Wherein the liquid crystal light valve includes a second substrate and a liquid crystal layer, and the liquid crystal layer is disposed between the display surface and the second substrate.

Wherein at least one electrochromic medium layer can be further arranged between the first electrode layer and the second electrode layer.

Description of drawings

In order to make the above and other purposes, features and advantages of the present invention more comprehensible, a preferred embodiment is given below and described in detail in conjunction with the accompanying drawings, wherein:

1 is a schematic diagram of a known organic electroluminescent display element;

2 is a schematic diagram of an organic electroluminescent display element according to a first preferred embodiment of the present invention;

3 is a schematic diagram of an organic electroluminescent display element according to a second preferred embodiment of the present invention;

4 is a schematic diagram of an organic electroluminescent display element according to a third preferred embodiment of the present invention;

5 is a schematic diagram of an organic electroluminescent display element according to a fourth preferred embodiment of the present invention; and

FIG. 6 is a schematic diagram of an organic electroluminescent display element according to a fifth preferred embodiment of the present invention.

Detailed ways

FIG. 2 is a schematic diagram of an organic electroluminescent display element according to a first preferred embodiment of the present invention. Please refer to FIG. 2, the organic electroluminescent display element of the present invention is mainly composed of a substrate 200, a first electrode layer 202, an organic functional layer 204, a second electrode layer 206 and an electrochromic medium layer 208. . Wherein, the substrate 200 usually uses a glass substrate or other transparent substrates; the first electrode layer 202 is disposed on the substrate 200, the first electrode layer 202 is, for example, a transparent electrode layer, and its material is usually a transparent conductive material such as indium tin oxide; and The second electrode layer 206 is disposed on the first electrode layer 202. The second electrode layer 206 is, for example, a metal electrode, and its material is usually aluminum, calcium, or magnesium-silver alloy.

The organic functional layer 204 is disposed between the first electrode layer 202 and the second electrode layer 206 . The organic functional layer 204 is usually a multi-layer organic thin film, for example, composed of a hole injection layer 204a, a hole transport layer 204b, an organic electroluminescent layer 204c, an electron transport layer 204d and an electron injection layer 204e. It is worth noting that since the light in the organic electroluminescent display element is mainly generated by the organic electroluminescent layer 204c, the above-mentioned hole injection layer 204a, hole transport layer 204b, electron transport layer 204d and electron injection layer 204e And other multi-layer films can also be selectively produced.

Taking a passive matrix display as an example, the first electrode layer 202 and the second electrode layer 206 are, for example, a plurality of mutually perpendicular strip structures, and the mutually perpendicular area is regarded as a pixel area. When an electric current passes between the first electrode layer 202 and the second electrode layer 206, electrons and holes are combined in the organic functional layer 204 to generate excitons, which can make the organic functional layer 204 produce different The light emitting mechanism of the color. In other words, the organic electroluminescent display element is driven by current, and converts electrical energy into light energy to achieve the purpose of display.

Please refer to FIG. 2 , the electrochromic medium layer 208 is disposed between the organic functional layer 204 and the second electrode layer 206 . The material of the electrochromic medium layer 208 is, for example, transition metal oxide, Prussian compound, viologen, conductive polymer, transition enzyme lanthanide complex and metal polymer or metal phthalocyanine fuel.

Wherein, the transition metal oxide is, for example, WO ₃ , MoO ₃ , V ₂ O ₅ , Nb ₂ O ₅ , Ir(OH) ₃ or NiO _x H _y . The Prussian compound is, for example, Fe ^III Fe ^II (CN) ₆ ) ⁻ , Fe ^III Fe ^III (CN) ₆ ) or Fe ^II Fe ^II (CN) ₆ ) ²⁻ . Viologens are, for example, 1'-disubstituted-4,4'-bipyridyl salts. The conductive polymer is, for example, polypyrrole, polythiophene, polyaniline or polyethylenedioxythiophene. Transitionase lanthanide complexes and metallopolymers are, for example, hydrogenase and nitrosylmolybdenum complexes or.

Taking the above-mentioned transition metal oxide as an example, the electrochromic medium layer 208 can be divided into two types:

Type N: MoO ₃ +x(M ⁺ +e ^- )→N _x Mo _(1-X) ^V1 Mo _x ^V O ₃

    Transparent         Dark Blue

Nb ₂ O ₅ +x(M ⁺ +e ^- )→M _x Nb ₂ O ₅

  Transparent   Dark Blue

P type: Ir(OH) ₃ →Ir O ₂ H ₂ O+H ⁺ +e ^-

  Transparent   Blue-black

NiO _x M _y →(Ni _(1-z) ^II Ni _z ^III )O _x M _(yz) +M ⁺ +ze ^-

    Transparent     Brown-black

For organic electroluminescence display elements of bottom emission type (bottom emission), the above-mentioned P-type electrochromic medium layer 208 is preferred, and NiO _x M _y , M+=H ⁺ , Li ⁺ , Na ⁺ and K ⁺ are preferred. Among them, the electrochromic medium layer 208 takes Li _x Ni _1-x O as an example, and a target material obtained by mixing nickel oxide and lithium oxide powder can be used, and combined with sputtering or laser evaporation, on the ITO glass substrate Deposit Li _x Ni _1-x O thin films. The electrochromic medium layer 208 is NiO _x My _y as an example, and pure nickel can be used as a target material to carry out magnetron sputtering under an _O2 atmosphere of 10m Torr to obtain a nickel oxide film, and then the obtained nickel oxide film The NiO _x M _y film can be obtained after treatment with 1M KOH solution.

It can be seen from the above chemical formula that when the current passes between the first electrode layer 202 and the second electrode layer 206 , the electrochromic medium layer 208 will undergo oxidation and reduction reactions, and present different colors and changes in transmittance. In other words, the electrochromic medium layer 208 can be used as a selective light valve, and can present different colors and changes in transmittance according to whether the pixels on the organic electroluminescence display device are lit or not.

Among them, for the non-lighted pixel area, since no current is passed through, the electrochromic medium layer 208 can produce a light-shielding effect, so as to effectively reduce the reflected light of external light entering the organic electroluminescent element, while for the lighting In the pixel area, due to the introduction of current, the electrochromic medium layer 208 can produce a light-transmitting effect, and the external light can penetrate and reflect from here, thereby increasing the brightness of the lit pixel area, so it can effectively improve the brightness of the pixel area as a whole. The contrast ratio of the organic electroluminescent display element under strong light further increases the recognition effect of the display element.

Based on the above, in this embodiment, the electrochromic medium layer 208 is disposed between the organic functional layer 204 and the second electrode layer 206, so as to reduce external strong light from entering between the organic functional layer 204 and the second electrode layer 206. reflection interface. However, those skilled in the art should be able to infer that the electrochromic medium layer 208 of the present invention can also be arranged between the first electrode layer 202 and the organic functional layer 204 (not shown), or can be arranged in the above-mentioned hole Between any two layers of the injection layer 204a, the hole transport layer 204b, the organic electroluminescent layer 204c, the electron transport layer 204d, and the electron injection layer 204e (not shown), the recognition effect of the display element can also be increased.

FIG. 3 is a schematic diagram of an organic electroluminescent display element according to a second preferred embodiment of the present invention. Please refer to FIG. 3 , the organic electroluminescent display element of the present invention is mainly composed of a first substrate 300 , a first electrode layer 302 , an organic functional layer 304 , a second electrode layer 306 and a selective light valve 400 . Wherein, the first substrate 300 usually uses a glass substrate or other transparent substrates, and the first substrate 300 has a display surface 310; the first electrode layer 302 is disposed on the first substrate 300, and the first electrode layer 302 is, for example, a transparent The electrode layer is usually made of a transparent conductive material such as indium tin oxide; the second electrode layer 306 is disposed on the first electrode layer 302, and the second electrode layer 306 is, for example, a metal electrode layer, and its material is usually aluminum, calcium Or magnesium-silver alloy and other metal materials; the organic functional layer 304 is disposed between the first electrode layer 302 and the second electrode layer 306, and the organic functional layer 304 is the same as the above-mentioned embodiment and is composed of multilayer organic thin films; The light valve 400 is disposed on the display surface 310 of the first substrate 300 .

The selective light valve 400 is mainly composed of a second substrate 410 , a third substrate 420 and a liquid crystal layer 430 . Wherein, the second substrate 410 and the third substrate 420 are, for example, glass substrates or other transparent substrates, and the third substrate 420 is disposed on the display surface 310 of the first substrate 300, and the liquid crystal layer 430 is disposed on the second substrate 410 and the third substrate. between the substrates 420 . The characteristics of the liquid crystal light valve determine whether the external light passes or not, which corresponds to the non-lit pixel area shielding the external light to effectively reduce the reflected light of the external light entering the organic electroluminescent element, while for the lit pixel area The external light is allowed to penetrate to increase the brightness of the illuminated pixel area, which can effectively improve the contrast of the organic electroluminescent display element under strong light, thereby increasing the recognition effect of the display element.

It is worth noting that the selective light valve 400 (i.e. liquid crystal light valve) used in this embodiment does not need to be attached to the outside of the second substrate 410 and the third substrate 420. The upper and lower polarizers, this embodiment only uses the light valve characteristics of the liquid crystal layer 430 when the voltage is driven to achieve the effect of selective shading, so as to increase the recognition of the organic electroluminescent display element.

FIG. 4 is a schematic diagram of an organic electroluminescent display element according to a third preferred embodiment of the present invention. Please refer to FIG. 4 , the main structure of the organic electroluminescent display element is roughly the same as that of the second preferred embodiment, and the same parts will not be described again. The difference is that the above-mentioned third substrate 420 is omitted, and the liquid crystal layer 430 is configured. on the display surface 310 of the first substrate 300 . In other words, the liquid crystal layer 430 and the OLED share the same substrate only by fabricating thin film transistors and alignment films on the display surface 310 of the first substrate 300 , which can further reduce the thickness of the organic electroluminescent display element.

The first to third preferred embodiments mentioned above are all equipped with a selective light valve (that is, an electrochromic medium layer or a liquid crystal light valve) in the organic electroluminescence display element, but familiar with this item Those skilled in the art can infer that the present invention is not limited to disposing one kind of selective light valve in the organic electroluminescent display element, and multiple kinds of selective light valves can also be disposed simultaneously, which are illustrated below.

FIG. 5 is a schematic diagram of an organic electroluminescent display element according to a fourth preferred embodiment of the present invention. Please refer to Fig. 5, which mainly combines the selective light valve 400 (i.e. liquid crystal light valve) described in the first preferred embodiment and the second preferred embodiment, as can be seen from the figure, organic electroluminescence The display element has two kinds of selective light valves, the electrochromic medium layer 208 and the selective light valve 400 (ie, the liquid crystal light valve), so that the recognition of the organic electroluminescent display element can be further increased.

FIG. 6 is a schematic diagram of an organic electroluminescent display element according to a fifth preferred embodiment of the present invention. It mainly combines the selective light valve 400 (that is, the liquid crystal light valve) described in the first preferred embodiment and the third preferred embodiment. It can be seen from the figure that the organic electroluminescent display element has both The two selective light valves, the electrochromic medium layer 208 and the selective light valve 400 (i.e., the liquid crystal light valve), can not only further increase the recognition degree of the organic electroluminescent display element, but also reduce the organic electroluminescence Displays the thickness of the component.

In summary, the organic electroluminescent display element of the present invention has at least the following advantages:

1. The organic electroluminescent display element of the present invention can shield the external light for the non-lighted pixel area, so as to reduce the reflective situation of the interface between the metal electrode layer and the organic functional layer, and then improve the performance of the organic electroluminescent element under strong light. Recognition, contrast and display quality.

2. The organic electroluminescent display element of the present invention can allow external light to penetrate the pixel area for lighting, and utilize the incident light from the outside to further increase the luminous efficiency of the organic light-emitting material.

Although the present invention has been described above with a preferred embodiment, it is not intended to limit the present invention. Any skilled person may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore The scope of protection of the present invention is subject to the content defined in the scope of the patent application.

Claims (20)

1. An organic electroluminescent display element, comprising at least: a substrate; a first electrode layer configured on the substrate; a second electrode layer configured on the first electrode layer; an organic functional layer disposed between the first electrode layer and the second electrode layer; and At least one electrochromic medium layer is arranged between the first electrode layer and the second electrode layer. 2. The organic electroluminescent display element according to claim 1, wherein the organic functional layer is disposed on the first electrode layer, and the electrochromic medium layer is disposed on the organic functional layer and the organic functional layer. between the second electrode layer. 3. The organic electroluminescent display element according to claim 1, wherein the electrochromic medium layer is disposed on the first electrode layer, and the organic functional layer is disposed on the electrochromic medium layer and the second electrode layer. 4. The organic electroluminescent display device as claimed in claim 1, wherein the organic functional layer comprises at least one organic electroluminescent layer. 5. The organic electroluminescence display element according to claim 4, wherein the organic functional layer further comprises a hole injection layer, and the hole injection layer is disposed on the first electrode layer and the organic electroluminescence between layers. 6. The organic electroluminescence display element as claimed in claim 5, wherein the organic functional layer further comprises a hole transport layer, and the hole transport layer is configured between the hole injection layer and the organic electroluminescence between layers. 7. The organic electroluminescence display element according to claim 6, wherein the organic functional layer further comprises an electron injection layer, and the electron injection layer is disposed on the second electrode layer and the organic electroluminescence layer between. 8. The organic electroluminescent display element according to claim 7, wherein the organic functional layer further comprises an electron transport layer, and the electron transport layer is disposed between the electron injection layer and the electroluminescent layer . 9. The organic electroluminescence display element according to claim 8, wherein the electrochromic medium layer is configured on the hole injection layer, the hole transport layer, the organic electroluminescence layer, the Between any two layers of the electron transport layer and the electron injection layer. 10. The organic electroluminescence display element as claimed in claim 1, wherein the material of the electrochromic medium layer is selected from transition metal oxides, Prussian compounds, viologens, conductive polymers, transition enzymes At least one of the lanthanide coordination compound, the metal polymer and the metal phthalocyanine fuel. 11 . The organic electroluminescence display device according to claim 10 , wherein the transition metal oxide is selected from at least one of WO ₃ , MoO ₃ , V ₂ O ₅ and Nb ₂ O ₅ . 12. The organic electroluminescent display element according to claim 10, wherein the Prussian compound is selected from (Fe ^III Fe ^II (CN) ₆ ) ^- , Fe ^III Fe ^III (CN) ₆ and (Fe ^II Fe ^II (CN) ₆ ) ^{2 -} at least one of them. 13. The organic electroluminescence display element according to claim 10, wherein the viologen comprises 1'-disubstituted-4,4'-bipyridyl salt. 14 . The organic electroluminescence display device as claimed in claim 10 , wherein the conductive polymer is at least one selected from polypyrrole, polythiophene, polyaniline and polyethylenedioxythiophene. 15. The organic electroluminescent display element according to claim 10, wherein the transition enzyme lanthanide complex and metal polymer are selected from at least one of hydrogenase and nitrosyl molybdenum complex . 16. An organic electroluminescence display element, comprising at least: A first substrate having a display surface; a first electrode layer configured on the first substrate, wherein the display surface and the first electrode layer are respectively located on opposite sides of the first substrate; a second electrode layer configured on the first electrode layer; an organic functional layer disposed between the first electrode layer and the second electrode layer; and A selective light valve is disposed on the display surface. 17. The organic electroluminescence display device as claimed in claim 16, wherein the selective light valve comprises a liquid crystal light valve. 18. The organic electroluminescence display element according to claim 17, wherein the liquid crystal light valve comprises a second substrate, a third substrate and a liquid crystal layer, and the third substrate is disposed on the display surface , and the liquid crystal layer is disposed between the second substrate and the third substrate. 19. The organic electroluminescent display element according to claim 17, wherein the liquid crystal light valve comprises a second substrate and a liquid crystal layer, and the liquid crystal layer is disposed between the display surface and the second substrate . 20. The organic electroluminescence display element according to claim 16, wherein at least one electrochromic medium layer is further arranged between the first electrode layer and the second electrode layer.

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