Invented by Dong-soo Choi, Jin-woo Park, Tae-Seung Kim, Samsung Display Co Ltd
The Samsung Display Co Ltd invention works as followsAn organic display device comprises a first substrate with an array of light emitting pixels on it, and a second substrate opposite the first substrate. A frit seal surrounds the array and interconnects first and second substrates. “A film structure is interposed between the array of organic emitting pixels on the second substrate, and contacts the second substrate as well as the array.
Background for Organic Light Emitting Display with Frit Seal
The present invention is a device that emits light organically, and, more specifically, encapsulates the organic light-emitting display.
In general, an OLED consists of an anode layer, a hole layer transport layer and organic emission layer. These layers are formed sequentially on the anode layer. A cathode layer is then formed over the resultant structure. When a voltage applied to such a structure a hole from the anode layer is injected into the organic emissions layer via the hole transportation layer. An electron from the cathode layer is injected into the organic emissions layer via electron transport layer. “The organic emission layer emits energy when excitons in the excited state make the transition to the ground state as described above.
However organic thin layer formed from an organic compound with low thermal resistance is likely to degrade by moisture and a cathode electrolyte formed on the organic thick layers can have lowered performance due to oxidation. The organic thin layers must be hermetically closed to prevent oxygen or moisture from contacting them. FIG. FIG. 1 shows a cross sectional view of a typical organic light emitting device. As shown in FIG. As shown in FIG. The substrate 100 contains a thin-film transistor with a semiconductor layer and gate electrodes, source electrodes, and drain electrodes. After forming the moisture absorption layer on the surface of the sealing substrate, which faces the organic light-emitting diode, the sealant 120 is used to adhere the substrate 100 with the sealing substrate.
The invention may provide an organic light-emitting display device that includes: a first surface; a second surface; an array formed of organic light-emitting pixels between the two substrates; the array having a top face facing the second surface; a frit sealing interposed between both surfaces while surrounding the array. A film structure consisting of one or more layers, with a portion positioned between the second surface and the array.
In the device described above, the film structure can cover a substantial portion of the upper surface. The film structure can also include a portion that is interposed between first and second substrates, but not between the array and second substrate. The film structure can contact the frit sealing. The film structure does not have to contact the frit. The array can comprise a plurality of electrodes.
Still, in the device of the present invention, the film structure can comprise an organic layer and a layer of protection interposed between the arrays and the organic layer. The protective layer is configured to prevent the components from the organic layer diffusing into arrays. The protective layer can be made up of at least one material selected from silicon oxide or silicon nitride. The organic resin layer can be urethane-acrylic resin. The array can emit visible light from the second substrate.
Further, in the device described above, at least a part of the film may be substantially translucent with respect to visible lights. The film structure can have a reflectance of visible light that is smaller or substantially equal to the second substrate. The film structure can have a refractory indice substantially equal to the material forming a layer that contacts the film structure. The film structure can be substantially nonconductive. The frit seal can be made of one or more materials from the following group: magnesium oxide, calcium oxide, barium oxide, sodium oxide, potassium oxide, potassium oxide, tellurium oxide, tellurium oxide, aluminum oxide, silicon dioxide, phosphorous oxide, ruthenium, rubidium, and rubidium oxides, as well as copper, titanium, tungsten, antimony, and bismuth oxides.
The invention also provides a method for making an organic light-emitting device. This may include: providing an unfinished item comprising first substrate and second surface substrate with an interior surface opposite the former, first array of pixels, first frit, second frit, first array interposed, first array facing second surface substrate and first array interposed, first array facing second surface substrate and a film structure consisting of one or more layers interposed, first structure contacting interior surface and first top surfaces, second structure consisting of one or two layered film, second array between
The method of providing an unfinished product can include providing the first surface and the arrays 1 and 2 formed on it, providing a second surface and the curable materials formed on it, arranging the two substrates so that the curables are located between them, and interposing first and secondary frits in between. The curable materials may be in contact with the first frit. Curing the curable materials may involve first curing some of it near the first frit before curing the rest. The UV light can be used to cure the part in proximity of the first frit. The curable material can be heated to cure the remaining portion. The first array can comprise a plurality of electrodes.
The following paragraphs will describe the various embodiments and embodiments in the present invention with reference to the drawings that accompany the description. The drawings may exaggerate the thickness or length of the layers for illustration purposes.
The organic light-emitting display (OLED), is a display consisting of an array organic light-emitting diodes. Organic light emitting devices are solid-state devices that include organic materials and are adapted for generating and emitting light when electrical potentials are applied.
OLEDs are generally classified into two types based on how the electrical current stimulating the display is delivered. FIG. FIG. 8A shows a schematic view of an OLED passive matrix 1000 in exploded form. FIG. FIG. 8B shows a simplified schematic structure of a matrix active type OLED 1001. Both configurations include OLED pixels overlaid on a substrate 1002. The OLED pixels have an anode, a cathode, and an organic layer. “When anode 1004 is charged with an electrical current, the pixels are lit and the organic layer emits visible light.
Referring to FIG. The passive matrix OLED design (PMOLED), shown in 8A, includes elongate anode strips 1004 that are arranged perpendicularly to elongate cathode strips 1006, with organic layers between them. The intersections between the strips of cathode and anode define individual pixels of OLEDs where light is produced and emitted when the corresponding strips 1004 and 1006 are appropriately excited. The PMOLEDs are relatively easy to manufacture.
Referring to FIG. The active matrix OLED includes driving circuits 10012 that are arranged between a substrate 1002 with an array of pixels. Each AMOLED pixel is defined by the common cathode 1006 and the anode 1004, electrically isolated from all other anodes. Each driving circuit 10012 is connected to an OLED pixel anode 1004. It’s also coupled to a data and scan line 1018. In some embodiments, scan lines 1018 provide scan signals to select rows of driving circuits and data lines 1016 provide data signals for specific driving circuits. Data signals and scans signals are used to stimulate the local driving 1012 circuits, which then excite the anodes 10004 in order to emit light.
In the AMOLED illustrated, the local driving loops 1012, data lines 1016, and scan lines are buried under a planarization 1014 which is interposed between pixel arrays and substrates 1002. The planarization 1014 is a flat surface that provides the top planar surface for the organic light-emitting pixel array. Planarization layer 1014 can be made of inorganic or organic materials and may consist of multiple layers, although it is shown as one layer. Local driving circuits are usually formed using thin film transistors and arranged as a grid under the OLED pixels. Local driving circuits 1012 can be made from organic materials including organic TFT. AMOLEDs are desirable for displaying data because of their fast response time. AMOLEDs are also more energy efficient than passive matrix OLEDs.
The substrate 1002 is a structural support for OLED pixels and circuits. The substrate 1002 may be made of rigid or flexible materials and opaque or transparent materials such as glass, plastic or foil. Each OLED diode or pixel is made up of the organic layer 10010, anode 1004, and cathode 1006. Anode 1004 is energized by an electrical current. The cathode 1006 injects electrons, and anode 10004 injects hole. In some embodiments, anode and cathode are inverted. The cathode forms on the substrate 1002 while the anode opposely is arranged.
One or more organic layers are interposed between cathode 1006 and anode 1004. Between the cathode and anode 1004, at least one emissive layer or light emitting film is present. One or more organic light emitting compounds may be used in the light emitting layer. The light emitting layer emits visible light typically in one color, such as white, blue, green or red. In the embodiment shown, an organic layer 1010 acts as a layer that emits light. Between the cathode and anode, additional layers can be added, such as a hole injecting layer, an electronic transporting and electron injection layer.
Hole transporting or injection layers can interpose between the light-emitting layer 1010, and the anode 10004. Between the cathode 1006 and the light-emitting layer 10010, electron transporting or injecting layers may be placed. The electron injection layer reduces the work function required to inject electrons into the light emitting 1010 from the cathode 1000 by using the electron injection layer. The hole injection layer also facilitates the injection of holes into the light emitting 1010 from the anode 1004. The electron and hole transporting layers allow carriers to be injected into the light emitting layer from respective electrodes.
In some embodiments, one layer can serve both electron transport and injection functions or both holes injection and transport functions. In some embodiments one or more layers are missing. In some embodiments one or more of these organic layers may be doped with materials that aid in the injection or transportation of carriers. “In embodiments in which only one organic material is present between the anode and cathode, this organic layer can include both an organic light-emitting compound as well as certain functional materials to help with the injection or transportation.
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