CN100421259C - Organic Light Emitting Display Panel - Google Patents

Abstract

The present invention discloses an organic light emitting display panel, which includes a substrate defining a plurality of first pixel regions, a second pixel region and a third pixel region, a heating circuit structure and a plurality of programmable organic light emitting diodes respectively arranged in each of the first pixel regions, the second pixel region and the third pixel region on the heating circuit structure, wherein the heating circuit structure is used to define the light emitting color of each organic light emitting diode in each of the first pixel regions and each of the second pixel regions.

Description

Organic Light Emitting Display Panel

technical field

The present invention relates to an organic light emitting display panel (organic light emitting display panel, OLED panel), in particular to a pixel with a heating circuit (heating circuit) that can directly produce different colors by using a heating process (heating process). ) organic light emitting display panel.

Background technique

With the rapid development of science and technology, thin, light, power-saving and portable intelligent information products have filled our living space, and monitors have played a very important role in it, whether it is mobile phones, personal digital assistants or notebook computers. A display is required as an interface for man-machine communication. In recent years, displays have made great progress under the demand of high image quality, large screen and low cost. Among them, with the successful development of organic materials, organic light-emitting displays have a simple structure and excellent operating temperature, contrast, viewing angle, etc. Advantages have gradually attracted attention in the display market, and even have a tendency to surpass liquid crystal displays (liquid crystal display, LCD) or cathode ray tube (cathode ray tube, CRT) displays.

Since the organic light-emitting material is a current-driven light-emitting element, and can generate light of different brightness according to the magnitude of the current passing through it, as long as it is matched with a color filter of an appropriate color, the organic light-emitting display can make full use of this characteristic to display Generate red, blue, and green lights of different gray levels to further enable the display to produce colorful images.

Please refer to Figure 1 and Figure 2. FIG. 1 and FIG. 2 are schematic diagrams of a conventional organic light emitting display panel 10 fabricated using three-color pixels. As shown in FIG. 1 , a conventional organic light emitting display panel 10 is formed on a transparent substrate 12 , and the transparent substrate 12 may be a glass substrate, a plastic substrate or a quartz substrate. A driving circuit is provided on the surface of the transparent substrate 12, and an insulating layer 16 is arranged on it. A plurality of organic light-emitting diodes arranged in a matrix are formed on the insulating layer 16, and color filters of appropriate colors are formed on each organic light-emitting diode. A red pixel 18 , a blue pixel 22 and a green pixel 24 are formed, and adjacent red pixels 18 , blue pixels 22 and green pixels 24 form a color pixel 20 .

Please refer to FIG. 2 . FIG. 2 is a schematic cross-sectional view of the organic light emitting display panel 10 shown in FIG. 1 along the line A-A′. As shown in FIG. 2, each pixel 18, 22 and 24 of the organic light emitting display panel 10 (see FIG. 1) all includes a transparent conductive layer (transparentconductive layer) 26 formed on the surface of the insulating layer 16. As the anode (anode) of each organic light emitting diode; an organic luminous layer (organic luminous layer) 28 formed on the surface of the transparent conductive layer 26, and a metal layer (metal layer) formed on the surface of the organic luminous layer 28 ) 32, this layer is used as the cathode (cathode) of each OLED.

Wherein, the transparent conductive layer 26 includes an indium tin oxide (indium tin oxide, ITO) layer or an indium zinc oxide (indium zinc oxide, IZO) layer, and the organic light-emitting layer 28 includes respectively formed on the transparent conductive layer 26. A hole transport layer (hole transport layer, HTL) (not shown), an emitting layer (emitting layer, EL) (not shown), and an electron transport layer (electron transport layer, ETL) (not shown). The metal layer 32 is made of metal or alloy with low work function, and generally includes a magnesium metal layer (Mg layer), an aluminum metal layer (Al layer), or a lithium/silver alloy layer (Li/Ag alloy layer).

In the prior art, red, blue, and green pixels are mostly generated by combining organic light-emitting diodes capable of emitting white light with red, blue, and green color filters to form color pixels. However, this method needs to set color filters, and needs to control the alignment accuracy in the process to avoid unevenness of the three-color light, so it often has additional restrictions on its layout, which further reduces the aperture ratio ( aperture ratio) decreased. Therefore, developing a new organic light-emitting display panel to solve the problems existing in the prior art has become an important subject at present.

Contents of the invention

The technical problem to be solved by the present invention is to provide an organic light emitting display panel, especially an organic light emitting display panel with a heating loop structure and programmable organic light emitting diodes.

The organic light emitting display panel provided in the embodiment of the present invention includes: a substrate defining a plurality of first pixel regions, second pixel regions and third pixel regions; a heating circuit structure; Programmable organic light emitting diodes in each of the first pixel area, the second pixel area and the third pixel area on the loop structure. Wherein, the heating loop structure includes a plurality of first heating lines and a plurality of second heating lines respectively arranged in the first pixel area and the second pixel area, to define each first pixel area and each second pixel area. The emission color of an organic light-emitting diode.

Since the organic light-emitting display panel of the present invention is provided with a heating circuit under part of the organic light-emitting diodes, and then the organic light-emitting diodes emitting red light and green light are manufactured through the heating process, therefore, not only does not need to use color filters, Moreover, the problem of alignment accuracy can be avoided, the aperture ratio can be increased, and different organic films do not need to be provided for different colors, making the manufacturing steps simple and avoiding additional problems due to complicated processes. In a word, the organic light emitting display panel of the present invention has the advantages of low cost, simple heat treatment process and high yield.

Description of drawings

1 and 2 are schematic diagrams of an existing OLED display panel;

3 to 8 are schematic diagrams of an organic light emitting display panel according to a first embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view of an organic light emitting display panel according to a second embodiment of the present invention.

Explanation of reference signs

10 organic light emitting display panel 12 substrate

16 insulation layer 18 red pixels

22 green pixels 24 blue pixels

26 Transparent electrode 28 Organic light-emitting layer

32 metal layer 110 organic light emitting display panel

112 substrate 114 pixel area

114a first pixel area 114b second pixel area

114c Third pixel area 116 Wire

117 first insulating layer 118 first contact hole

124 The first heating line 126 The second heating line

128 Ground electrode 130 Heating circuit

131 Second insulating layer 132 Organic light-emitting diode

133 transparent electrode 134 blue pixel

135 organic light-emitting layer 136 green pixels

137 metal layer 138 red pixels

140 color pixels 212 substrate

214a first pixel area 214b second pixel area

214c third pixel area 217 first insulating layer

224 The first heating line 226 The second heating line

231 Second insulating layer 231a First dielectric material

231b Second Dielectric Material 232 Organic Light Emitting Diode

Detailed ways

Please refer to FIG. 3 to FIG. 8 . FIG. 3 to FIG. 8 are schematic diagrams of an organic light emitting display panel 110 according to a preferred embodiment of the present invention. As shown in FIG. 3 , the organic light-emitting display panel 110 of the present invention includes a transparent substrate 112. The transparent substrate 112 can be a glass substrate, a plastic substrate or a quartz substrate, and a pixel array area (pixel array area, not shown) is defined on the transparent substrate 112. shown) and a peripheral circuit area (not shown). A plurality of pixel areas (pixel areas) 114 are defined in the pixel array area for accommodating each OLED element and a pixel driving circuit matched with them, and the peripheral circuit area is for accommodating a control circuit. Since the focus of the present invention has nothing to do with the peripheral circuit area, it will not be described in detail. It should be noted that the pixel area 114 is composed of a plurality of first pixel areas 114a, second pixel areas 114b and third pixel areas 114c. In a preferred embodiment of the present invention, the first pixel area 114a, the second pixel area 114b and the third pixel area 114c are respectively used as a red pixel area, a green pixel area and a blue pixel area.

The organic light emitting display panel 110 also includes a wire 116 formed on the surface of the substrate 112, wherein the wire 116 and the signal line (signalline, not shown) on the organic light emitting display panel 110 are formed by patterning the same metal layer, and the wire 116 includes tungsten Wire (W line), chrome wire (Cr line) or other conductive metal wire.

As shown in FIG. 4 , the organic light emitting display panel 110 includes a first insulating layer 117 formed on the substrate 112 , and the first insulating layer 117 covers each pixel area 114 and the wire 116 . A plurality of first contact holes 118 are disposed in the first insulating layer 117 , and each first contact hole 118 respectively exposes a part of the wire 116 . The first insulating layer 117 includes a silicon oxide layer (TEOS-SiO ₂ layer), a silicon oxide layer or a silicon nitride layer using tetraethoxysilane as a reactive gas.

As shown in FIG. 4 and FIG. 5, the organic light emitting display panel 110 further includes a plurality of first heating wires (first heating wire) 124 and a plurality of second heating wires (second heating wire) 126 formed on the transparent substrate 112, each The first heating wires 124 and the second heating wires 126 are respectively electrically connected to the first wires 116 through the first contact holes 118 . At the same time, each of the first heating lines 124 and each of the second heating lines 126 respectively cover a part of each of the first pixel regions 114a and the second pixel regions 114b. Each of the first heating wires 124 and each of the second heating wires 126 are made of ITO or IZO, and the widths of each of the first heating wires 124 and each of the second heating wires 126 are approximately the same.

A ground electrode (ground electrode) 128 is additionally formed on the substrate 112, and the ground electrode 128 is electrically connected to each first heating wire 124 and each second heating wire 126, so as to maintain each first heating wire 124 and each second heating wire as far as possible. The voltage above 126 is stable, and forms a heating loop structure 130 together with the wire 116 , the first heating wire 124 and the second heating wire 126 . In fact, the ground electrode 128 can also be a common electrode electrically connected to other voltages, as long as it can provide a stable voltage difference with the wire 116 for heating by each heating wire 124 , 126 .

As shown in FIG. 6 and FIG. 7, a second insulating layer 131 is formed on the substrate 112, the second insulating layer 131 covers the heating circuit structure 130, and a plurality of second contact holes (not shown) are arranged in the second insulating layer 131. display), and the second insulating layer 131 in the first pixel region 114a and the second pixel region 114b have different thicknesses. The thickness of the second insulating layer 131 is such that the distance between each organic light emitting diode 132 in the first pixel area 114a and the first heating line 124 is smaller than the distance between each organic light emitting diode 132 and the second heating line 126 in the second pixel area 114b .

In addition, the organic light emitting display panel 110 further includes a plurality of organic light emitting diodes 132 formed on the second insulating layer 131 and corresponding to each pixel region 114 . Each organic light emitting diode 132 includes a transparent electrode 133 formed on the second insulating layer 131, an organic light emitting layer 135 formed on the transparent electrode 133, and a metal layer 137 formed on the organic light emitting layer 135. . Wherein, each transparent electrode 133 can be an indium tin oxide layer or an indium zinc oxide layer, and is used as an anode (anode) of each organic light emitting diode 132, and the metal layer 137 can be a magnesium metal layer, an aluminum metal layer, A lithium metal layer or an alloy layer is used as a cathode of each OLED 132 . In fact, the metal layer 137 can completely cover all the pixel regions 114 or individually cover each pixel region 114 according to actual needs. Each transparent electrode 133 of each OLED 132 is electrically connected to a pixel circuit disposed on the surface of the substrate 112 through each second contact hole (not shown), so that each OLED 132 is driven by the pixel circuit to display images.

The organic light emitting layer 135 further includes a hole transport layer (not shown), a light emitting layer (not shown), and an electron transport layer (not shown) sequentially formed on the transparent electrode 133 . In addition, in actual application, a hole injection layer (not shown) can also be added between the transparent electrode 133 and the hole transport layer (not shown), or between the metal layer 137 and the electron transport layer An electron injection layer (not shown) is added between (not shown) to improve the problems caused by the organic light emitting layer 135 and the anode/cathode junction, so as to facilitate the injection of electrons or holes into the organic light emitting layer 135 . Furthermore, a light-emitting layer with electron transport capability or a hole-transport layer with light-emitting capability can also be selected to reduce the use of organic thin films, thereby simplifying the manufacturing process.

It is worth noting that each organic light emitting diode 132 of the present invention is an organic light emitting diode that can be programmed according to temperature. The emission color of each OLED 132 is defined by temperature, and the chemical change is an irreversible chemical change. In other words, once an OLED 132 is defined by a predetermined temperature, its emission color will not change again. For example, once a predetermined temperature is used to make an OLED 132 produce red light output, the OLED 132 will only output red light.

As shown in FIG. 8, the wire 116 is electrically connected to a voltage source through an external power line (not shown), so when an external voltage is applied to the heating circuit structure 130 through the wire 116, a corresponding current will flow. Each of the first heating wires 124 and each of the second heating wires 126 starts heating, so as to use different temperatures to define the emission colors of the organic light emitting diodes 132 above. As mentioned above, since the thickness of the second insulating layer 131 (not shown) in the first pixel region 114a (see FIG. 4 ) is smaller than that of the second insulating layer 131 in the second pixel region 114b (see FIG. 4 ), Therefore, during the heating process, each organic light emitting diode 132 in the first pixel area 114a has a higher temperature, while the temperature of each organic light emitting diode 132 in the second pixel area 114b is slightly lower than that of each organic light emitting diode 132 in the first pixel area 114a. The temperature of the organic light emitting diode, the third pixel region 114c (see FIG. 4 ) below which the first heating line 124 or the second heating line 126 is not provided is not affected by the heating process, so that the first pixel region 114a, the second pixel region 114c The organic light emitting diodes 132 in the second pixel area 114b and the third pixel area 114c become organic light emitting diodes 132 of different colors to respectively form red pixels 138, green pixels 136, and blue pixels 134, while adjacent red pixels 138, green Pixel 136 and blue pixel 134 form a color pixel 140 .

It is worth mentioning that the width of each first heating line 124 and each second heating line 126 is approximately the same as the width of each organic light emitting diode 132, so as to improve the uniformity of heating, thereby improving the uniformity of blue light, red light and green light. Spend. Moreover, each of the first heating wires 124 and each of the second heating wires 126 may have any shape, and is not limited to the stripe structure illustrated in the figure. Since the arrangement of organic light emitting diodes 132 emitting green light, red light, and blue light includes mosaic arrangement (Mosaic Type), triangle arrangement (Triangle Type) or stripe arrangement (Stripe Type), each first heating line 124 and each second heating line The heating wire 126 can also be in the form of a broken line or other forms. In fact, each of the first heating lines 124 and each of the second heating lines 126 can uniformly cover each pixel region 114 to be heated and achieve the purpose of uniform heating.

In addition, each pixel region 114 includes a pixel circuit disposed on the surface of the transparent substrate 112, and the circuit includes a plurality of thin film transistors (not shown) to drive each red pixel 138, green pixel 136 and each organic light emitting diode 132 in the blue pixel 134, and make each organic light emitting diode 132 generate light emitting brightness corresponding to the driving circuit. At the same time, the heating circuit provided by the present invention can be applied not only to active matrix panels, but also to passive matrix panels.

Please refer to FIG. 9 . FIG. 9 is a schematic cross-sectional view of an organic light emitting display panel according to a second embodiment of the present invention. As shown in FIG. 9, in the second embodiment of the present invention, its structure is similar to that of the aforementioned first embodiment, and also includes a substrate 212 and a first insulating layer 217, and a first pixel region 214a is also arranged on it. , a second pixel region 214b, and a third pixel region 214c, and an organic light emitting diode 232 that can be programmed according to temperature is also formed in each pixel region 214a, 214b, 214c, and also includes a heating circuit, with a respective setting The first heating line 224 and the second heating line 226 under the first pixel area 214a and the second pixel area 214b. The main difference is that the second insulating layer 231 of this embodiment includes a variety of dielectric materials with different heat transfer coefficients, so as to utilize material differences to form a temperature difference between the first pixel region 214 a and the second pixel region 214 b. Under the condition of satisfying the above conditions, the second insulating layer 231 can have various compositions and structures, which are not listed here. The structure of the second insulating layer 231 in the preferred embodiment of the present invention will be described below only by taking FIG. 9 as an example. and production method. As shown in FIG. 9 , the manufacturing method of the second insulating layer 231 in this embodiment is as follows: firstly, a second dielectric material layer 231b is formed on the substrate 212, and then through a back-etching process, the first pixel region 214a is The second dielectric material layer 231b is selectively removed, and a first dielectric material layer 231a is formed in the first pixel region 214a to separate the first heating line 224 from the organic light emitting diode 232, and the first dielectric material layer The electrical material layer 231a is made of a material with a high heat transfer coefficient relative to the second dielectric material layer 231b. Therefore, in the first pixel region 214a, the thermal resistance between the heating circuit and the organic light emitting diode 232 is lower than that in the second pixel region 214b. The thermal impedance between the heating circuit and the OLED 232, in other words, under the condition that the first heating wire 224 and the second heating wire 226 are heated with the same power, the OLED 232 in the first pixel region 214a will have a higher thermal resistance. temperature, so the purpose of defining the emission color of each organic light emitting diode at different temperatures can be achieved.

In the aforementioned two embodiments, the thermal impedance between the heating circuit and each OLED is changed through the difference in the thickness or material of the second insulating layer, so that the heating circuit can define the light emission of the OLEDs at different temperatures. However, the present invention is not limited thereto, as long as different colors of OLEDs can be defined by using different temperatures. For example, the thickness of the second insulating layer and the material difference can be combined to form different thermal impedances, or the heating circuit can be directly adjusted appropriately so that the first heating wire and the second heating wire have different heating output powers. For example, the thickness of the first heating wire and the second heating wire can be changed so that they have different heating powers, or a plurality of disconnected wires can be formed, for example, at least one first wire and a second wire are electrically connected to the The first heating line and the second heating line heat the organic light-emitting diodes in each pixel area through different external voltage sources, or use the same external voltage through the difference in resistance between the first wire and the second wire The source heats each organic light emitting diode in each pixel region, so as to form organic light emitting diodes of different colors by using different heating powers.

Compared with the prior art, the organic light emitting display panel of the present invention is provided with a heating circuit under part of the organic light emitting diodes, and then a heating process is used to manufacture the organic light emitting diodes emitting red light and green light. In this way, not only do not need to use color filters, but also avoid the problem of alignment accuracy, and can increase the aperture ratio, and do not need to set different organic films corresponding to different colors, but can ensure a simple manufacturing process, so it can be The yield can be effectively increased and the manufacturing cost of the organic light-emitting display panel can be greatly reduced.

The above descriptions are only preferred implementations of the present invention, and all equivalent changes and modifications made within the scope of protection described in the claims of the present invention fall within the scope of protection required by the present invention.

Claims (10)

1. An organic light-emitting display panel, comprising: A substrate, on which a plurality of first pixel regions, second pixel regions and third pixel regions are defined; a second insulating layer; a plurality of organic light emitting diodes; and A heating loop structure, the heating loop structure comprising: at least one wire disposed on the substrate; a first insulating layer formed on the substrate, the layer has a plurality of first contact holes exposing the wires; A plurality of first heating lines formed on the first insulating layer, the first heating lines cover part of the first pixel region, and are electrically connected to the wires through the first contact holes; a plurality of second heating lines formed on the first insulating layer, the second heating lines cover a part of the second pixel region, and are electrically connected to the wires through the first contact holes; and a ground electrode electrically connected to each of the first heating wires and each of the second heating wires; Wherein the second insulating layer is formed on the substrate and covers the heating circuit structure, and the plurality of organic light emitting diodes are respectively formed on the second insulating layer in each of the first pixel regions and each of the second pixels. In the region and each third pixel region, the heating loop structure makes the first pixel region, the second pixel region and the third pixel region have different temperatures from each other. 2. The organic light-emitting display panel as claimed in claim 1, wherein the wires are electrically connected to an external power source, so that the first heating wire and the second heating wire are respectively opposite to the organic light emitting diodes on them. LEDs for heating. 3. The organic light emitting display panel as claimed in claim 2, wherein the first heating line and the second heating line respectively use different temperatures to define the corresponding organic light emitting diodes, so that The organic light emitting diodes in the pixel area, each second pixel area and each third pixel area generate light of different colors. 4. The organic light emitting display panel according to claim 1, wherein the second insulating layer located above the first heating line and the second insulating layer located above the second heating line have different thickness. 5. The organic light emitting display panel as claimed in claim 1, wherein the first heating wire and the second heating wire have different thicknesses. 6. The organic light emitting display panel of claim 1, wherein the second insulating layer comprises a plurality of dielectric materials having different heat transfer coefficients. 7. The organic light emitting display panel according to claim 1, wherein each of the first heating lines is used to heat each organic light emitting diode in each of the first pixel regions, so that the organic light emitting diodes located in each of the first pixel regions Each organic light emitting diode emits green light; each second heating line is used to heat each organic light emitting diode in each second pixel area, so that each organic light emitting diode located in each second pixel area emits red light. 8. The organic light emitting display panel as claimed in claim 7, wherein each organic light emitting diode that has not been heated emits blue light. 9. The organic light emitting display panel as claimed in claim 1, wherein each of the organic light emitting diodes comprises: a transparent electrode formed on the second insulating layer, each transparent electrode is used as an anode of each organic light emitting diode; an organic light-emitting layer formed on the transparent electrode; and A metal layer formed on the organic light emitting layer, each metal layer is used as a cathode of each organic light emitting diode. 10. The organic light emitting display panel as claimed in claim 1, wherein each of the first heating wires and each of the second heating wires is made of indium tin oxide or indium zinc oxide.

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