This application claims the priority benefit of Taiwan application serial no. 98146353, filed on Dec. 31, 2009. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of specification.
1. Field of the Invention
The present invention relates to a light emitting device, and more particularly, to an electroluminescence device.
2. Description of Related Art
As an emissive device, the electroluminescence device has the advantages of no view angle limit, low fabrication cost, high response speed (about more than one hundred times faster than the response speed of the liquid crystal), power saving, adaptability to direct current driving in portable devices, broad operating temperature range, light weight, as well as providing miniature and low-profile design Therefore, the electroluminescence device has a great development potential and is expected to be the next generation of flat panel display.
One typical electroluminescence device includes a top electrode layer, a bottom electrode layer, and a light emitting layer sandwiched between the two electrode layers. The bottom electrode layer is usually made of a transparent conductive material for transmission of lights emitted by the light emitting layer. However, as the electroluminescence device becomes larger and larger in size, a voltage drop occurred due to the resistance of the power lines may cause a clear difference between the voltage of the pixels adjacent the power input end and the voltage of the pixels far away from the power input end. Because luminance of each pixel of the electroluminescence device depends on the current flowing through that pixel, the clear voltage difference would result in the poor overall light emitting uniformity of the electroluminescence device.
Accordingly, the present invention is directed to an electroluminescence device which can improve the overall light emitting uniformity of the electroluminescence device.
The present invention provides an electroluminescence device including a substrate, a pixel array, a plurality of lead line sets, a plurality of driving devices, and at least one power transmission pattern. The substrate includes a display region and a peripheral circuit region around the display region. The pixel array is disposed in the display region and has a plurality of pixel structures. Each of the pixel structures includes at least one active element and a light emitting element electrically connected to the at least one active element. The lead line sets are disposed in the peripheral circuit region of the substrate and electrically connected with the pixel array. Each of the lead line sets has a plurality of lead lines. Each driving device is electrically connected with one corresponding lead line set. The power transmission pattern is disposed in the peripheral circuit region of the substrate and between the adjacent lead line sets. One end of the power transmission pattern is electrically connected to the light emitting element of the pixel array, and another end of the power transmission pattern is electrically connected to one corresponding driving device.
The present invention provides an electroluminescence device including a substrate, a pixel array, a plurality of lead line sets, at least one driving devices, and at least one power transmission pattern. The pixel array is disposed in the display region of the substrate and has a plurality of pixel structures. Each pixel structure includes at least one active element and a light emitting element electrically connected to the at least one active element. The lead line sets are disposed on the substrate and electrically connected with the pixel array. Each of the lead line set has a plurality of lead lines. The driving device is electrically connected one of the lead line sets. The power transmission pattern is disposed between the adjacent lead line sets, with one end of the power transmission pattern being electrically connected with the light emitting element of the pixel array and another end of the power transmission pattern being electrically connected to one corresponding driving device.
In view of the foregoing, the power transmission pattern is disposed between the adjacent lead line sets, with one end of the power transmission pattern being electrically connected to the light emitting element of the pixel array and another end of the power transmission pattern being electrically connected with one corresponding driving device. The provision of the power transmission pattern can reduce the voltage drop on the power lines, thereby improving the overall light emitting uniformity of the electroluminescence device.
In order to make the aforementioned and other features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.
Referring first to
The substrate 100 includes a display region 10 and a peripheral circuit region 20 around the display region 10. The substrate 100 may be a transparent substrate such as a transparent glass substrate or a transparent flexible substrate. The substrate 100 is mainly used to support components of the electroluminescence device. In order to enable the light emitted by the electroluminescence device to penetrate through the substrate 100, the substrate 100 is made of a transparent or light transmitting material. Electroluminescence devices that emit light from the substrate 100 are also generally referred to as bottom-emitting electroluminescence devices.
Referring to
In the present embodiment, referring to
In the present embodiment, the active elements T1, T2 are illustrated as top-gate thin-film transistors (also referred to as poly-silicon thin-film transistors). However, this is for the purposes of illustration only and therefore should not be regarded as limiting. In other embodiments, the active elements T1, T2 may also be bottom-gate thin-film transistors (also referred to as amorphous silicon thin-film transistor). In addition, the pixel structures P shown in
As shown in
The first electrode layer 130 is disposed on the surface of the insulating layer 106 and is electrically connected with the drain D2 of the active element T2. In the present embodiment, the first electrode layer 130 is electrically connected to the drain metal layer DM2 of the active element T2 via a contact window C formed in the insulating layer 106. The first electrode layer 130 is a transparent electrode layer that may be made of metal oxide such as indium tin oxide or indium zinc oxide. Besides, another insulating layer 108 is formed over the first electrode layer 130. The insulating layer 108 has an opening 150 that exposes the first electrode layer 130. In each pixel region 110, the area occupied by the opening 150 is substantially equal to or slightly less than the area occupied by the first electrode layer 130.
The light emitting layer 160 is disposed on the first electrode layer 130 exposed from the opening 150. The light emitting layer 160 may be an organic light emitting layer or inorganic light emitting layer. The electroluminescence device may be referred as an organic electroluminescence device or an inorganic electroluminescence device depending upon the material of the light emitting layer 160. Besides, the light emitting layer 160 of the light emitting element O of each pixel structure P has a red organic light emitting pattern, green organic light emitting pattern, blue organic light emitting pattern, or multi-layered (e.g. white, orange, and/or purple) light emitting pattern formed by mixing a desired spectrum of lights.
The second electrode layers 170 may be formed by an unpatterned electrode layer over the light emitting layer 160 and extends to the surface of the insulating layer 108. In the present embodiment, the second electrode layers 170 of the light emitting elements O of all pixel structures P are electrically connected with one another because they form a single layer (unpatterned electrode layer). The second electrode layer 170 may be a metal electrode layer or a transparent conductive layer. Besides, the multiple insulating layers 108, 106 are formed between the second electrode layer 170 and the active elements T1, T2 on the substrate 100. Therefore, at least two insulating layers 108, 106 are interposed between the second electrode layer 170 and the active elements T1, T2, scan line SL, data line DL, power line PL and lead line sets LS1, LS2.
In another embodiment, the light emitting element O may further include an electron injection layer, a hole injection layer, an electron transmission layer, and a hole transmission layer.
As shown in
The driving devices 30s, 30g are electrically connected with the lead line sets LS1, LS2, respectively. In the present embodiment, the driving device 30s is also referred to as a source driving device and the driving device 30g is also referred to as a gate driving device. The source driving devices 30s are electrically connected with the data lines DL via the lead line set LS1. The gate driving devices 30g are electrically connected with the scan lines SL via the lead line set LS2. In one embodiment of the present invention, as shown in
Referring to
In the present embodiment, the power transmission pattern 40a is electrically connected with two adjacent driving devices 30s. In other words, because the power transmission pattern 40a is disposed between two adjacent lead line sets LS1, the power transmission pattern 40a can be electrically connected with the driving devices 30s that are electrically connected with the adjacent lead line sets LS1. Similarly, the power transmission pattern 40b is electrically connected with two adjacent driving devices 30g. In other words, because the power transmission pattern 40b is disposed between two adjacent lead line sets LS2, the power transmission pattern 40b can be electrically connected with the driving devices 30g that are electrically connected with the adjacent lead line sets LS2. More specifically, in the present embodiment, as shown in
Besides, the driving devices 30s, 30g may be electrically connected with the lead line sets LS1, LS2 via an anisotropic conductive adhesive. Taking the driving device 30s and the lead line set LS1 as an example, as shown in
In addition, as shown in
Furthermore, in one embodiment of the present invention, the power transmission patterns 40a, 40b are electrically connected to a ground potential. Therefore, the power transmission patterns 40a, 40b are used to transmit a ground potential. In other words, after the ground potential is transmitted to the power transmission patterns 40a, 40b through the circuit boards 50a, 50b and the driving devices 30a, 30g, the ground potential is further transmitted to the second electrode layer 170 of the light emitting element O of the pixel array 110. This causes the voltage source Vss to which the second electrode layer 170 of the light emitting diode O is electrically connected to be the ground potential, and the lead line L1′ (or lead line L2′) transmits the potential of the voltage source VDD.
In another embodiment of the present invention, the power transmission patterns 40a, 40b are electrically connected to a driving voltage ranging from about −10 V to 0 V. Therefore, the power transmission patterns 40a, 40b are used to transmit a driving voltage. In other words, after the driving voltage is transmitted to the power transmission patterns 40a, 40b through the circuit boards 50a, 50b and the driving devices 30s, 30g, the driving voltage is further transmitted to second electrode layer 170 of the light emitting element O of the pixel array 110. This causes the potential of the voltage source VDD to which the second electrode layer 170 of the light emitting diode O is electrically connected to be the driving voltage and, in this case, the lead line L1′ (or lead line L2′) transmits the ground potential of the voltage source Vss.
In order to electrically connect the second electrode layer 170 to the power transmission pattern 40a, the electroluminescence device of the embodiment of
While the repair line RL1, RL2 is illustrated as being only disposed between the power transmission pattern 40a and the lead line set LS1 in the embodiment of
In the embodiments described above, it is illustrated that the driving circuits 30s, 30g, lead line sets LS1, LS2, power transmission pattern 40a, 40b, and circuit board 50a, 50b are disposed in the peripheral circuit region 20 at two sides of the display region 10. However, this is for the purposes of illustration only and should not be regarded as limiting. In alternative embodiments, the driving circuits, lead line sets, power transmission patterns, and circuit boards may also be disposed in the peripheral circuit region 20 at one side of the display region 10. Besides, the present invention is not intended to limit the number of the driving circuits, 30s, 30g, lead line sets LS1, LS2, and power transmission patterns 40a, 40b. Rather, the number of the driving circuits 30s, 30g, lead line sets LS1, LS2, and power transmission patterns 40a, 40b may vary depending upon the size of the electroluminescence device. Moreover, it is not intended to require one power transmission pattern be disposed between every two adjacent lead line sets. One or more power transmission pattern(s) may be disposed between the adjacent lead line sets based on actual requirements of the electroluminescence device.
In summary, the power transmission power is disposed between two adjacent lead line sets, with one end of the power transmission pattern being electrically connected to the light emitting element of the pixel array and another end of the power transmission pattern being electrically connected with one corresponding driving device. Therefore, the provision of the power transmission pattern can reduce the voltage drop on the power line, thereby improving the overall light emitting uniformity of the electroluminescence device.
In addition, the power transmission pattern is disposed in the spare space between the existing lead line sets, and therefore, extra space is not required for the power transmission pattern.
Moreover, electrical connection with the power transmission pattern is achieved through the dummy pad on the flexible circuit board of existing driving circuit. Therefore, an extra flexible circuit board is not required for electrical connection with the power transmission pattern.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
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98146353 | Dec 2009 | TW | national |