1. Field of the Invention
The present invention relates to an organic electroluminescent display panel and a fabricating method thereof, and more particularly to a full-color OLED display panel and a fabricating method thereof.
2. Description of the Related Art
The light-emitting principle adopted by organic light-emitting display panels is different from the technology of a currently prevailing LCD panel using liquid crystal as a light switch medium. The basic structure of an OLED includes an organic fluorophor sandwiched between two layers of electrodes. The fluorophor can emit light under an appropriate voltage. Therefore, a backlight source is not needed, and the OLED display can exhibit graphs and texts with a thin structure. Moreover, in order to improve the OLED display panel and make it into an optimal display element, the research on full-color technology in recent years has become the key point. Several common methods are described as follows.
As shown in
However, the color saturation of the organic light-emitting display panel 10 is unsatisfactory, and the ratio based on NTSC color saturation is about 66%, so a large amount of power is consumed in order to tune a full-color image. Moreover, though the polarizing plate 16 improves the contrast of the panel display, and only a portion of the lights can pass through, which reduces the overall brightness of the panel by approximately 42%, the polarizing plate 16 increases the material cost. Furthermore, high-precise masks and high-precise alignment apparatuses are used in related processes of the organic light-emitting layers 121, 122, 123 for precisely defining the corresponding coverage regions. However, during the fabricating, the materials of different light-emitting layers may be stacked with each other due to mask deformation or misalignment, thus resulting in the problem of abnormal light color mixing of the panel.
The white organic light-emitting layer 212 is usually formed by adding a complementary orange light-emitting material to a blue light-emitting material in order to exhibit white light. However, as the white-light spectrum has a wide distribution range, the light source transmittance of the white light relative to the color filter 22 is very poor (the transmittance of the red filter portions 223 is about 16%, the transmittance of the green filter portions 224 is about 53%, and the transmittance of the blue filter portions 225 is about 16%), thus attenuating the brightness. After the white light passes through the blue filter portions 225 and the green filter portions 224, the color saturation of the blue and green lights passing through is very poor, so a large amount of power consumption must be taken into consideration when tuning and designing a full-color display panel. Moreover, the NTSC color saturation is also very poor, about 60%. As the white organic light-emitting layer 212 is formed by mixing the light-emitting materials of at least two color lights, the thickness variation or the changes in material doping concentration of the organic light-emitting layer 212 may affect the distribution of the white-light spectrum, i.e., the adjustment range of the control parameters in the fabricating processes becomes narrow.
As the thickness and structure of the red-light resonance layer 415, green-light resonance layer 416, and blue-light resonance layer 417 may affect the result of the conversion of white light into each color light, and as the variation in thickness or the changes of the material doping concentration of the red, green, and blue organic light-emitting layers 414, 413 and 412 may also affect the distribution of the white-light spectrum, the fabricating process is very difficult.
As it is similar to the OLED structure 1a in
a)-6(b) are schematic sectional views of conventional organic light-emitting display panels. The organic light-emitting display panels 60 and 60′ are panels disclosed in R.O.C. Patent No. I272865, and respectively include an organic light-emitting layer 612 for generating a blue light and an organic light-emitting layer 612′ for generating a blue-green light in an OLED, and a cathode 611 and an anode 613 sandwiching the organic light-emitting layer 612 or 612′ between them. The insulation layer 614 divides the anode 613 and the organic light-emitting layer 612 or 612′ into a plurality of divided lighting areas. The aforesaid OLED structure 61 is formed and stacked on a color filter 62, as shown in
As shown in
As shown in
In view of the above, some of the conventional full-color OLED display panels cannot achieve red, green, and blue lights of preferred chroma and brightness, some are unstable in specifications and characteristics due to process variations and are difficult to control, and some have extremely complicated processes because the process window of the process parameters is too narrow. Therefore, the present invention provides a full-color OLED display panel with preferred optical characteristics and a simple fabricating process and a fabricating method thereof, so as to solve the problems in the conventional art.
The present invention is directed to providing an OLED display panel and a fabricating method thereof, wherein the OLED structure generates red, green and blue lights with purer chroma, and the color filter allows red, green and blue lights with a preferred color saturation to pass through.
The present invention is also directed to providing an OLED display panel with a simple fabricating process and a fabricating method thereof, wherein a wide-open mask is adopted instead of a high-precise mask, and the fine optical characteristics of the OLED display panel are still maintained.
In order to achieve the above objectives, the present invention provides a full-color OLED display panel and a fabricating method thereof. The display panel comprises a full-color organic light-emitting device and a colored filter device stacked on the light-exit surface of the full-color organic light-emitting device. The full-color organic light-emitting device comprises a first electrode, a plurality of second electrodes, a first light-emitting layer sandwiched between the first electrode and a portion of the second electrodes, a second light-emitting layer sandwiched between the first electrode and a portion of the second electrodes, and a third light-emitting layer sandwiched between the first electrode and a portion of the second electrodes. The colored filter device comprises a substrate, and a plurality of first color filter portions and a plurality of second color filter portions disposed on the surface of the substrate. The first color filter portions allow a first color light emitted from the first light-emitting layer to pass through, and the second color filter portions allow a second color light emitted from the second light-emitting layer to pass through. The third light-emitting layer is further stacked on the surfaces of the first light-emitting layer and the second light-emitting layer. The colored filter device further comprises a plurality of third color filter portions, which allow a third color light emitted from the third light-emitting layer to pass through.
The present invention provides a full-color OLED display panel and a fabricating method thereof. The display panel comprises a full-color organic light-emitting device and a colored filter device stacked on the light-exit surface of the full-color organic light-emitting device. The full-color organic light-emitting device comprises a first electrode, a plurality of second electrodes, a first light-emitting layer sandwiched between the first electrode and a portion of the second electrodes, and a second light-emitting layer sandwiched between the first electrode and portions of the second electrodes and the first light-emitting layer. The colored filter device comprises a substrate, and a plurality of first color filter portions, a plurality of second color filter portions and a plurality of third color filter portions disposed on the surface of the substrate. The first color filter portions allow a first color light emitted from the first light-emitting layer to pass through, and the second color filter portions and the third color filter portions each allow rays with different wavelengths in a second color light emitted from the second light-emitting layer to pass through.
The fabricating method of a full-color OLED display panel has the following steps. First, a colored filter device is provided. Then, a plurality of second electrodes and an insulating layer for separating the plurality of second electrodes are formed on the colored filter device. Next, a first light-emitting layer is deposited on a first electrode assembly in the plurality of second electrodes, a second light-emitting layer is deposited on a second electrode assembly in the plurality of second electrodes, and a third light-emitting layer is deposited on the first light-emitting layer, the second light-emitting layer, and a third electrode assembly in the plurality of second electrodes. Afterwards, a first electrode is formed on the third light-emitting layer.
The fabricating method of a full-color OLED display panel has the following steps. First, a colored filter device is provided. Then, a plurality of second electrodes and an insulating layer for separating the plurality of second electrodes are formed on the colored filter device. Next, a first light-emitting layer is deposited on a first electrode assembly in the plurality of second electrodes, and a second light-emitting layer is deposited on a second electrode assembly and a third electrode assembly in the plurality of second electrodes. Afterwards, a first electrode is formed on the second light-emitting layer.
The invention will be described according to the appended drawings in which:
a)-6(b) are schematic sectional views of a full-color OLED display panel of the present invention;
a)-8(f) are schematic views of the fabricating process of the full-color OLED display panel according to the present invention;
The accompanying drawings are included to provide a further understanding of the invention, and to explain the technical features of the invention clearly.
The colored filter device 72 includes a substrate 726, and a plurality of first color filter portions 723, a plurality of second color filter portions 724, and a plurality of third color filter portions 725 disposed on the surface of the substrate 726. The first color filter portions 723 allow a first color light (for example, red) emitted from the first light-emitting layer 712 to pass through. The second color filter portions 724 allow a second color light (for example, green) emitted from the second light-emitting layer 713 to pass through. The third color filter portions 725 allow a third color light (for example, blue) emitted from the third light-emitting layer 714 to pass through. The first color filter portions 723, the second color filter portions 724, and the third color filter portions 725 are separated by a black matrix 722, so as to avoid improper light mixing. In order to planarize the surface of the colored filter device 72 to facilitate the stacking of the second electrodes 719 and the insulating layer 615, a planarization layer 721 is needed to cover the surfaces of the filter portions of the substrate 726 and the black matrix 722.
The full-color OLED display panel 70 has the following advantages.
1. The first light-emitting layer 712, second light-emitting layer 713, and third light-emitting layer 714 can emit light individually, so the frequency spectrums of various emitted color lights are narrow. Compared with the white light emitted from the conventional white organic light-emitting unit, the light transmittance of various color lights of the present invention after passing through the filter portions is superior, and thus the luminance performance thereof can be greatly improved.
2. Each color light is filtered by the colored filter device 72, thus having a better color saturation. As such, while tuning the full-color image, the light utilization is improved, thus saving power and obtaining the NTSC color saturation of above 100%.
3. As the colored filter device 72 has the black matrix 722 and various filter portions, the contrast of various color lights can be improved without attaching an additional polarizing plate, thus saving costs.
4. Even if the materials of two different light-emitting layers partially overlap each other due to mask deformation or misalignment, as the light transmittance of the filter portions of a specific color light to the other two color lights is low, the abnormal color mixing of the panel can be effectively alleviated.
5. A wide-open mask is used instead of a high-precision mask when a light-emitting layer of a color light is formed, thus saving costs, increasing the output, and improving the yield.
The colored filter device 82 includes a substrate 826 and a plurality of second color filter portions 824 and third color filter portions 825 disposed on the surface of the substrate 826. The second color filter portions 824 allow a second color light (for example, green) emitted from the second light-emitting layer 813 to pass through. The third color filter portions 825 allow a third color light (for example, blue) emitted from the third light-emitting layer 814 to pass through. If the first light-emitting layer 812 emits a red light, due to the preferred color saturation of the red light, the first color filter portions that allow the red light to pass through will not need to be used. The second color filter portions 824 and the third color filter portions 825 are separated by a black matrix 822, so as to avoid improper light mixing. In order to planarize the surface of the colored filter device 82 to facilitate the stacking or forming of the second electrodes 819 and the insulating layer 815, a planarization layer 821 is needed to cover the surface opposite the substrate 826. Further, a polarizing plate 827 is attached to the substrate 826 in order to improve the contrast.
The full-color OLED display panel 80 has the following advantages.
1. As the colored filter device 82 does not need the first color filter portions which allow the red light to pass through, the light transmittance of the red light after passing through the colored filter device 82 is superior, thus improving the light utilization and reducing the process of fabricating the first color filter portions.
2. As the color saturation of each color light is preferable, while tuning the full-color image, the light utilization is improved, thus saving power and obtaining the NTSC color saturation of above 100%.
3. Even if the materials of two different light-emitting layers partially overlap each other due to mask deformation or misalignment, as the light transmittance of the filter portions of a specific color light to the other two color lights is low, the abnormal color mixing of the panel can be effectively alleviated.
4. Further, a polarizing plate 827 is attached to the substrate 826 in order to improve the contrast.
a)-9(f) are schematic views of the fabricating process of the full-color OLED display panel according to the present invention. Referring to
The above embodiments can be applied in an active or passive OLED display panel, and a top- or bottom-emission type OLED display panel.
The first light-emitting layer 912 and second light-emitting layer 913 each emit lights of a first color light (red) and a second color light (blue-green) after being electrically excited. Further, an insulating layer 915 separates the second electrodes 919 into the first electrode assembly 916, the second electrode assembly 917, and the third electrode assembly 918, and also separates the first light-emitting layer 912 and the second light-emitting layer 913. Though the first light-emitting layer 912 is defined by a high-precise mask, the second light-emitting layer 913 defined by a wide-open mask can overlay the first light-emitting layer 912 and the insulating layer 915. Therefore, the number of the high-precise masks can be reduced to a minimum so as to save costs, increase output per a time unit and improve production yield. Though the second light-emitting layer 913 is overlaid on the first light-emitting layer 912, the first color filter portions 723 of the colored filter device 72 corresponding to the first light-emitting layer 912 can filter the second light.
The colored filter device 92 includes a substrate 926, and a plurality of first color filter portions 923 disposed on the surface of the substrate 926, a plurality of second color filter portions 924, and a plurality of third color filter portions 725. The first color filter portions 923 allow a first color light emitted from the first light-emitting layer 912 to pass through. The second color filter portions 924 allow a portion of a second color light with specified wavelengths (for example, green) emitted from the second light-emitting layer 913 to pass through. The third color filter portions 725 allow another portion of a second color light with specified wavelengths (for example, blue) emitted from the second light-emitting layer 913 to pass through. The first color filter portions 923, the second color filter portions 924, and the third color filter portions 925 are separated by a black matrix 922, so as to avoid improper light mixing. In order to planarize the surface of the colored filter device 92 to facilitate the stacking of the second electrodes 919 and the insulating layer 915, a planarization layer 921 is needed to cover the surfaces of the filter portions of the substrate 926 and the black matrix 922. The second light-emitting layer 913 can be a single blue-green organic light-emitting layer or a stacked assembly of a blue organic light-emitting layer and a green organic light-emitting layer.
The first color filter portions 923 allow a portion (red) of a first color light with specified wavelengths (orange) emitted from the first light-emitting layer 912′ to pass through. The second color filter portions 924 allow a portion of a second color light with specified wavelengths (green) emitted from the first light-emitting layer 912′ to pass through. The third color filter portions 925 allow a third color light (for example, blue) emitted from the third light-emitting layer 914′ to pass through. The first light-emitting layer 912′ can be a single orange organic light-emitting layer or a stacked assembly of a red organic light-emitting layer and a green organic light-emitting layer.
Furthermore,
The aforementioned descriptions of the present invention are intended to be illustrative only. Numerous alternative methods may be devised by persons skilled in the art without departing from the scope of the following claims.
Number | Date | Country | Kind |
---|---|---|---|
095136850 | Oct 2006 | TW | national |
096130095 | Aug 2007 | TW | national |