CN1832192A - Double-sided light-emitting organic electroluminescent device and electronic device - Google Patents

Abstract

A dual-side light-emitting organic electroluminescent device. The device comprises a substrate having a first pixel region and an adjacent second pixel region. The first and second organic light emitting diodes are respectively disposed in the first and second pixel regions, wherein the first organic light emitting diode emits light in a direction opposite to the second organic light emitting diode. The first and second thin film transistors are disposed in the second pixel region, wherein the first thin film transistor is electrically connected to the first organic light emitting diode, and the second thin film transistor is electrically connected to the second organic light emitting diode.

Description

Double-sided light-emitting organic electroluminescent device and electronic device

technical field

The present invention relates to a flat display device, in particular to a double-sided organic electro-luminescence device (OELD), which is used to prolong the service life of the device.

Background technique

An organic electroluminescent device (OELD) or an organic light-emitting diode (OLED) is a self-luminous device using organic materials. The organic electroluminescent device is different from the liquid crystal display technology in that it does not require a backlight module, thus simplifying the process. With the rapid development of technology, organic electroluminescence devices will be applied to small-sized full-color display panels such as personal digital assistants and digital cameras in the future.

Typically, an organic light emitting diode includes: an anode, a cathode, and an organic light emitting layer disposed between the anode and the cathode. The organic light-emitting layer includes: a hole transport layer adjacent to the anode, an electron transport layer adjacent to the cathode, and a light-emitting layer arranged between the hole transport layer and the electron transport layer. When a potential difference is applied between the cathode and the anode, electrons are injected from the cathode into the electron transport layer, and pass through the electron transport layer and the light emitting layer. At the same time, holes are injected from the anode into the hole transport layer and pass through the hole transport layer. Afterwards, the electrons and holes will recombine near the interface of the light-emitting layer and the hole-transporting layer to release energy in the form of light.

Currently, organic electroluminescent devices are used for single-sided display. However, with the continuous development of electronic products, double-sided display has become a requirement for many products. For example, a folder type mobile phone. FIG. 3 shows a schematic plan view of a conventional double-sided light-emitting organic electroluminescent device. The double-sided light emitting organic electroluminescent device 10 includes a substrate 11 having two adjacent pixel regions 12 and 14 . A bottom-emitting OLED 16 and a TFT 20 are disposed in the pixel region 12 , and a top-emitting OLED 18 is disposed in the pixel region 14 . The thin film transistor 20 is electrically connected to the organic light emitting diode 16 , and the thin film transistor 22 is electrically connected to the organic light emitting diode 18 .

However, in order to achieve the purpose of double-sided light emission, the organic electroluminescence device 10 needs to divide the single pixel area into two pixel areas 12 and 14, resulting in a decrease in its aperture ratio (aperture ratio, AR). The pixel area 12 of the LED 16 . In order to maintain the brightness of the organic electroluminescence device 10 , the power consumption will be increased, and the service life of the organic electroluminescent device will be shortened.

Contents of the invention

In view of this, the purpose of the present invention is to provide a double-sided light-emitting organic electroluminescent device, which can improve the aperture ratio of the light-emitting device by changing the configuration of the thin film transistor, thereby prolonging its service life.

According to the above purpose, the present invention provides a double-sided light-emitting organic electroluminescent device. The double-sided light-emitting organic electroluminescent device includes a substrate with a first pixel area and an adjacent second pixel area. The first and second organic light emitting diodes are respectively arranged in the first and second pixel regions, wherein the light emitting direction of the first organic light emitting diode is opposite to that of the second organic light emitting diode. The first and second thin film transistors are arranged in the second pixel area, wherein the first thin film transistor is electrically connected to the first organic light emitting diode, and the second thin film transistor is electrically connected to the second organic light emitting diode.

Description of drawings

FIG. 1 shows a schematic plan view of a double-sided light-emitting organic electroluminescent device according to an embodiment of the present invention.

FIG. 2a shows a schematic cross-sectional view along line 2a-2a in FIG. 1 .

FIG. 2b shows a schematic cross-sectional view along line 2b-2b in FIG. 1 .

FIG. 3 shows a schematic plan view of a conventional double-sided light-emitting organic electroluminescent device.

simple notation

existing

10～Double-sided light-emitting organic electroluminescence device;

11 ~ substrate;

12, 14 ~ pixel area;

16 ~ Bottom-emitting organic light-emitting diodes;

18 ~ Top-emitting organic light-emitting diodes;

20, 22 ~ thin film transistors.

this invention

200～Double-sided light-emitting organic electroluminescence device;

100～substrate;

102 to the first pixel area;

104 to the second pixel area;

106～the first organic light emitting diode;

106a～transparent electrode;

106b, 108c～organic material layer;

106c～belongs to reflective electrodes;

108～the second light-emitting organic light-emitting diode;

108a～metal reflective layer;

108b～the first transparent electrode;

108d～the second transparent electrode;

110～the first thin film transistor;

111～grid;

112～the second thin film transistor;

113～gate dielectric layer;

114～flat layer;

115～active layer;

116～conductive layer;

117 ~ source/drain electrodes.

Detailed ways

The following describes the double-sided light-emitting organic electroluminescent device according to the embodiment of the present invention with reference to FIGS. 1, 2a and 2b. FIG. 2b respectively depicts schematic cross-sectional views along the lines 2a-2a and 2b-2b in FIG. 1 . Please refer to Figure 1. The double-sided light-emitting organic electroluminescent device 200 includes a substrate 100 , such as a glass or quartz substrate, which has a first pixel region 102 and an adjacent second pixel region 104 . In this embodiment, the first pixel area 102 and the second pixel area 104 form a sub-pixel area for displaying the same color, such as red, green, or blue.

The first organic light emitting diode 106 is disposed in the first pixel region 102 . The second organic light emitting diode 108 is disposed in the second pixel region 104 . In this embodiment, the light emitting direction of the first organic light emitting diode 106 is opposite to that of the second organic light emitting diode 108 . For example, the first OLED 106 is a bottom emitting OLED, which includes: a transparent electrode 106a, an organic material layer 106b and a metal reflective electrode 106c. As shown in FIG. 2 a , a transparent electrode 106 a , such as indium tin oxide (ITO) or indium zinc oxide (IZO), is disposed on the substrate 100 of the first pixel region 102 . The organic material layer 106b is disposed on the transparent electrode 106a. The organic material layer 106b is a multi-layer structure and includes: a hole transport layer (hole transport layer, HTL), an electron transport layer (electron transport layer, ETL), and a layer disposed between the hole transport layer and the electron transport layer Emissive layer (active or emissive layer). Here, in order to simplify the diagram, it is represented by a single-layer structure. The metal reflective electrode 106c is disposed on the organic material layer 106b, which may be made of aluminum, silver, gold, nickel, chromium, or other existing metal electrode materials. Furthermore, the light is emitted from the organic material layer 106b toward the substrate 100, as shown by the arrow in FIG. 2a.

The second organic light emitting diode 108 can be a top emitting organic light emitting diode, which includes: a metal reflective layer 108a, a first transparent electrode 108b, an organic material layer 108c and a second transparent electrode 108d. As shown in FIG. 2 b , the metal reflective layer 108 a is disposed on the substrate 100 of the second pixel region 104 , which may be made of aluminum, silver, gold, nickel, chromium, or other existing metal electrode materials. The first transparent electrode 108b, such as indium tin oxide (ITO) or indium zinc oxide (IZO), is disposed on the metal reflective layer 108a. The organic material layer 108c is disposed on the first transparent electrode 108b. As mentioned above, the organic material layer 108c is a multi-layer structure. To simplify the diagram, it is represented as a single-layer structure. The second transparent electrode 108d, such as indium tin oxide (ITO) or indium zinc oxide (IZO), is disposed on the organic material layer 108c. Furthermore, the light is emitted from the organic material layer 108c toward the second transparent electrode 108d, as shown by the arrow in FIG. 2b.

The first and second thin film transistors 110 and 112 are disposed on the substrate 100 of the second pixel area 104 and located below the second organic light emitting diode 108 . In this embodiment, the first and second thin film transistors 110 and 112 can be arranged in the second pixel region 104 arbitrarily, depending on design criteria. Furthermore, one of the first and second TFTs 110 and 112 is electrically connected to the first OLED 106 , and the other is electrically connected to the second OLED 108 . For example, the first thin film transistor 110 is electrically connected to the first organic light emitting diode 106 , and the second thin film transistor 112 is electrically connected to the second organic light emitting diode 108 .

As shown in FIG. 2 b , the first and second thin film transistors 110 and 112 respectively include: a gate 111 , a gate dielectric layer 113 , an active layer 115 and source/drain electrodes 117 . Moreover, a flat layer 114, such as a silicon nitride layer, is disposed between the first and second thin film transistors 110 and 112 and the second organic light emitting diode 108, and the second thin film transistor 112 is disposed in the flat layer 114 A conductive layer 116 is electrically connected to the upper second organic light emitting diode 108 .

The double-sided light-emitting organic electroluminescent device 200 of the present invention can be used in various electronic devices with display devices, such as personal digital assistants (PDAs), displays (display monitors), digital cameras (digital cameras), or mobile phones (cellular phones) ).

According to the present invention, since the thin film transistors are arranged in the pixel region with the top emitting OLED, the aperture ratio of the adjacent bottom emitting OLED can be increased. Compared with the existing double-sided light-emitting organic electroluminescent device, the brightness of the organic electroluminescent device can be improved, and the service life of the organic electroluminescent device can be prolonged.

Claims (8)

1. two-sided luminous organic electroluminescence device comprises:

Substrate has first pixel region and the second adjacent pixel region;

First and second Organic Light Emitting Diode, be arranged at respectively this first and this second pixel region, wherein the light emission direction of this first Organic Light Emitting Diode is in contrast to this second Organic Light Emitting Diode; And

First and second thin-film transistor is arranged at this second pixel region, and wherein this first film transistor is electrically connected to this first Organic Light Emitting Diode, and this second thin-film transistor is electrically connected to this second Organic Light Emitting Diode.

2. two-sided luminous organic electroluminescence device as claimed in claim 1, wherein this first Organic Light Emitting Diode is that bottom-emission diode and this second Organic Light Emitting Diode are the top light emitting diode.

3. two-sided luminous organic electroluminescence device as claimed in claim 2, wherein this bottom-emission diode comprises:

Transparency electrode is positioned on this substrate;

Organic material layer is positioned on this transparency electrode; And

The metallic reflection electrode is positioned on this organic material layer.

4. two-sided luminous organic electroluminescence device as claimed in claim 2, wherein this top light emitting diode comprises:

Metallic reflector; Be positioned at this first and this second thin-film transistor on;

First transparency electrode is positioned on this metallic reflector;

Organic material layer is positioned on this first transparency electrode; And

Second transparency electrode is positioned on this organic material layer.

5. two-sided luminous organic electroluminescence device as claimed in claim 1, wherein this first pixel region and this second pixel region are in order to show same color.

6. two-sided luminous organic electroluminescence device as claimed in claim 5, wherein this first pixel region and this second pixel region are formed time pixel region.

7. an electronic installation comprises two-sided luminous organic electroluminescence device as claimed in claim 1.

8. electronic installation as claimed in claim 7, wherein this electronic installation comprises personal digital assistant, display, digital camera or mobile phone.

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