CN100518422C - Double-sided display device - Google Patents

Abstract

The invention discloses a double-sided display device, which comprises a first substrate, a second substrate and a third substrate, wherein the upper surface of the first substrate is provided with a first organic light emitting diode; the second substrate is arranged above the first organic light emitting diode, and the lower surface of the second substrate is provided with a second organic light emitting diode. The stress buffer layer is used for filling the gap between the first substrate and the second substrate, sealing the first organic light-emitting diode on the first substrate and sealing the second organic light-emitting diode on the second substrate.

Description

Double-sided display device

technical field

The present invention relates to a double-sided display device, in particular to a double-sided organic electroluminescent display with a stress buffer structure.

Background technique

The forms of electronic products are becoming more and more diversified, and the double-sided display function has become the main feature of the new generation of electronic products. For example, the double-sided display device inside the mobile phone can display the main function window of the mobile phone on one side, and display the time on the other side. At present, the double-sided display devices produced in the industry are usually made of two single-sided display panels, such as two liquid crystal panels, a liquid crystal panel and an organic electroluminescent panel, or two organic electroluminescent panels. .

FIG. 1 is a known double-sided display device. A known double-sided display device 10 is formed by laminating a first display panel 11 and a second display panel 12 . The first display panel 11 has a transparent substrate 111 , a first electrode 112 , a light emitting layer 113 , a second electrode 114 and an encapsulation cover 115 . The first electrode 112 is formed on the transparent substrate 111 . The light emitting layer 113 is located between the first electrode 112 and the second electrode 114 . The edge of the packaging cover 115 is attached to the transparent substrate 111 and covers the second electrode 114 .

The second display panel 12 also has a transparent substrate 121 , a third electrode 122 , a light emitting layer 123 , a fourth electrode 124 and an encapsulation cover 125 . The third electrode 122 is formed on the transparent substrate 121 . The light emitting layer 123 is located between the third electrode 122 and the fourth electrode 124 . The edge of the packaging cover 125 is attached to the transparent substrate 121 and covers the fourth electrode 124 . The packaging cover 115 of the first display panel 11 is attached to the packaging cover 125 of the second display panel 12 to form a double-sided display device 10 .

As described above, the known double-sided display device 10 has two package covers 115 and 125 and two transparent substrates 111 and 121 . Therefore, the entire device is bulky, thick, and heavy. When it is applied to a medium-sized or large-sized display, it is easy to cause the substrate to bend due to external pressure or gravity, resulting in peeling of the light-emitting layer or electrodes. The present invention provides a double-sided display device to solve the above disadvantages.

Contents of the invention

The object of the present invention is to provide a double-sided display device, which is filled with a stress buffer material to prevent peeling or breaking of the organic light emitting diode, and has the function of waterproofing and preventing oxygen intrusion.

The double-sided display device of the present invention comprises a first substrate with a first organic light emitting diode on its upper surface; a second substrate with a second organic light emitting diode on its lower surface and located above the first organic light emitting diode. The stress buffer layer fills the gap between the first substrate and the second substrate, seals the first organic light emitting diode on the first substrate, and seals the second organic light emitting diode on the second substrate.

The stress buffer layer uses solid, liquid or colloidal anti-stress materials. Structurally, the stress buffer layer fills the gap between the upper and lower substrates, so the organic light-emitting diodes on the surface of the substrate can be fixed. If the material properties of the stress buffer layer can absorb water and oxygen, or can be waterproof and oxygen-proof, or add waterproof and oxygen-proof materials to the stress buffer layer, the waterproof and oxygen-proof functions can be enhanced.

Description of drawings

Fig. 1 is a known double-sided display device;

Fig. 2 is the first embodiment of the double-sided display device of the present invention; and

FIG. 3 is a second embodiment of the double-sided display device of the present invention.

[Description of main component symbols]

10 double-sided display device (known) 20 double-sided display device

11 First display panel 21 Lower substrate

111 Transparent Substrate 22 Organic Light Emitting Diode

112 first electrode 221 reflective electrode

113 light emitting layer 222 light emitting layer 114 second electrode

223 transparent electrode 115 package cover

23 upper substrate 12 second display panel

24 machine light emitting diodes

121 Transparent substrate 241 Reflective electrode

122 Third electrode 242 Light emitting layer

123 Light-emitting layer 243 Transparent electrode

124 fourth electrode 25 stress buffer layer

125 Capsule 26 Adhesive

30 double-sided display device 32 protective layer

Detailed ways

The double-sided display device of the present invention is hereby described in detail in conjunction with the accompanying drawings, and the preferred embodiments are listed as follows:

Please refer to FIG. 2 , which is a first embodiment of the present invention. The double-sided display device 20 includes a lower substrate 21 and an upper substrate 23 bonded by an adhesive 26 . Organic light emitting diodes 22 are disposed on the upper surface of the lower substrate 21 . Another organic light emitting diode 24 is disposed on the lower surface of the upper substrate 23 . Between the upper substrate 23 and the lower substrate 21, a stress buffer layer 25 is provided to fill the gap between the two substrates 21 and 23, and is used to seal the organic light emitting diode 22 on the lower substrate 21, and seal the organic light emitting diode 24 on the upper substrate. Substrate 23.

The stress buffer layer 25 can be solid, liquid or colloidal, which can fix the organic light emitting diodes on the surface of the substrate and prevent the two substrates 21 and 23 from being bent by external forces, causing the structural layers of the organic light emitting diodes 22 and 24 to Peeling or breaking. If the material properties of the stress buffer layer 25 can absorb water and oxygen, or can be waterproof and anti-oxygen, or add water-absorbing materials or oxygen-absorbing materials to the stress buffer layer, it can effectively prevent water vapor or oxygen from invading the OLEDs 22 and 24 .

Please refer to FIG. 3 , which is a second embodiment of the present invention. The same parts of the double-sided display device 30 as the first embodiment include the lower substrate 21 , the organic light emitting diodes 22 , the upper substrate 23 , the organic light emitting diodes 24 and the stress buffer layer 25 . However, the double-sided display device 30 also includes a protective layer 32 attached to the surfaces of the OLEDs 22 and 24 as a protective layer, and enhances the ability to prevent water vapor or oxygen from invading the OLEDs 22 and 24 .

In the above two embodiments, the OLED 22 has a transparent electrode 223 , a light emitting layer 222 and a reflective electrode 221 . The transparent electrode 223 is formed on the substrate 21 , so the organic light emitting diode 22 emits light toward the substrate 21 . Likewise, the organic light emitting diode 24 has a reflective electrode 241 , a light emitting layer 242 and a transparent electrode 243 . The reflective electrode 241 is formed on the substrate 23 , so the organic light emitting diode 24 emits light toward the substrate 23 . The reflective electrodes 221 and 241 can be metal electrodes. Incidentally, in order to improve the anti-reflection effect and avoid light leakage interference when both sides are simultaneously displayed, the reflective electrodes 221 and 241 can be covered with a dark or black insulating layer, or replaced with black electrodes, or added with anti-reflection materials or light-absorbing materials.

Between the electrode and the light-emitting layer is a region for hole or electron transfer. In the hole transport region, a hole injection layer or a hole transport layer may be selectively inserted. In the electron transport region, an electron injection layer or an electron transport layer may be selectively inserted.

The electron transport layer can be made of 8-hydroxyquinoline aluminum (Alq), tripolybenzimidazole (TPBI), anthracene derivatives, fluorine derivatives (fluorine, spirofluorine) and other materials, and then doped with alkali metal halides , alkaline earth metal halides, alkali metal oxides or metal carbonates and other n-type dopants to enhance their electron mobility.

The material of the electron injection layer can be a metal compound, and an alkali metal halide, an alkaline earth metal halide, an alkali metal oxide or a metal carbonate compound or an organic compound containing the above-mentioned n-type dopant with a good degree of coordination with the work function of the opaque electrode is used. layer.

The hole transport layer material can be allylamine compounds such as NPB (N,N-di(naphthalene-1-yl)-N,N-diphenyl-benzidene).

The material of the hole injection layer can be allylamine or CuPc and other cyanine compounds.

The manufacturing method of the double-sided display device 30 of the present invention is further described with the second embodiment. First, the transparent electrode 223 is formed on the lower substrate 21 . Organic layers such as a hole injection layer, a hole transport layer, a light emitting layer 222 , an electron transport layer, and an electron injection layer are sequentially formed. Next, a reflective electrode 221 is formed on the organic layers to form a complete organic light emitting diode 22 . Then the protective layer 32 is formed on the reflective electrode 221 . As for the substrate 23, the organic light emitting diode 24 and the protection layer 32 with the same structure are fabricated thereon by the same process.

Subsequently, the stress buffering material is provided on the surface of the substrate 21 or 23 by methods such as vapor deposition, inkjet coating, or drop-in-drop injection (ODF). An adhesive 26 is then coated on the lower substrate 21 or the upper substrate 23 , wherein the adhesive 26 surrounds the OLEDs 22 and 24 . At this time, the stress buffering material may be filled in the area surrounded by the adhesive 26 . Finally, the lower substrate 21 and the upper substrate 23 are assembled so that the OLED 22 is opposite to the OLED 24 , and the gap between the two substrates 21 and 23 is filled with stress buffer material to seal the two OLEDs 22 and 24 .

In all the above-mentioned embodiments, the transparent electrode can be a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO) or a thin metal layer, and the transparent substrate can be selected from a glass or plastic substrate. The structure of the present invention is not limited to be used in passive displays or active displays, so it can be combined with driving components such as thin film transistors.

When the present invention compares with known technology, possess following characteristic and advantage:

1. Better anti-external stress structure.

2. Simpler process.

3. Better waterproof and oxygen-proof performance.

The above detailed description is specific to the preferred embodiments of the present invention. The above embodiments are not intended to limit the scope of the present invention. All equivalent implementations or changes that do not depart from the present invention should be included in the scope of the present invention. Inside.

Claims (16)

1. A double-sided display device, comprising: first substrate; a first organic light emitting diode, disposed on the upper surface of the first substrate; a second substrate located above the first organic light emitting diode; a second organic light emitting diode disposed on the lower surface of the second substrate; and The stress buffer layer fills the gap between the first substrate and the second substrate, seals the first organic light emitting diode on the first substrate, and seals the second organic light emitting diode on the second substrate. 2. The double-sided display device according to claim 1, wherein the stress buffer layer further comprises a water-absorbing material. 3. The double-sided display device of claim 1, wherein the stress buffer layer further comprises a material that absorbs oxygen. 4. The double-sided display device of claim 1, wherein the stress buffer layer is solid. 5. The double-sided display device of claim 1, wherein the stress buffer layer is in a liquid state. 6. The double-sided display device as claimed in claim 1, wherein the stress buffer layer is colloidal. 7. The double-sided display device of claim 1, further comprising a protective layer attached to the surface of the first OLED. 8. The double-sided display device of claim 1, further comprising a protective layer attached to the surface of the second organic light emitting diode. 9. A method for manufacturing a double-sided display device, comprising: providing a first substrate; forming a first organic light emitting diode on the surface of the first substrate; providing a second substrate; forming a second organic light emitting diode on the surface of the second substrate; providing a stress buffer material on the surface of the first substrate where the first organic light emitting diode is located; and Combining the first substrate and the second substrate, making the first organic light emitting diode and the second organic light emitting diode face each other, filling the gap between the two substrates with the stress buffer material, and sealing the two organic light emitting diodes. 10. The method of claim 9, wherein the step of providing the stress buffering material injects the stress buffering material onto the surface of the first substrate by a drop method. 11. The method of claim 9, wherein the step of providing the stress buffering material is screen printing the stress buffering material on the surface of the first substrate. 12. The method of claim 9, wherein the step of providing the stress buffering material is evaporating the stress buffering material on the surface of the first substrate. 13. The method of claim 9, wherein the step of providing the stress buffering material is inkjet coating the stress buffering material on the surface of the first substrate. 14. The method of claim 9, further comprising: coating an adhesive on the first substrate and the second substrate, wherein the adhesive surrounds the first organic light emitting diode and the second organic light emitting diode; and The stress buffering material is filled in the area surrounded by the adhesive. 15. The method of claim 9, further comprising forming a protection layer on the surface of the first OLED. 16. The method of claim 9, further comprising forming a protective layer on the surface of the second OLED.

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