Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade
The emission uniformity of LED chips in the entire range of brightness and colors is the problem in LED displays manufacture process. It was approved that at lowering brightness gradations appearing the radiation nonuniformity between LED chips, and the higher disorders will be seen on the lesser em...
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| Format: | Article |
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Politehperiodika
2017-06-01
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| Series: | Tekhnologiya i Konstruirovanie v Elektronnoi Apparature |
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| Online Access: | https://tkea.com.ua/index.php/journal/article/view/201 |
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| author | V. P. Veleschuk O. I. Vlasenko Z. K. Vlasenko V. V. Shynkarenko Ya. Ya. Kudryk P. O. Sai V. V. Borshch |
| author_facet | V. P. Veleschuk O. I. Vlasenko Z. K. Vlasenko V. V. Shynkarenko Ya. Ya. Kudryk P. O. Sai V. V. Borshch |
| author_sort | V. P. Veleschuk |
| collection | DOAJ |
| description | The emission uniformity of LED chips in the entire range of brightness and colors is the problem in LED displays manufacture process. It was approved that at lowering brightness gradations appearing the radiation nonuniformity between LED chips, and the higher disorders will be seen on the lesser emission levels. The RGB LED chips, observed by us, were based on AlGaInP (red), In0.3Ga0.7N/GaN (green), and In0,2Ga0,8NN/ GaN (blue) and had nominal working current 20 mA. Analysis of the current-voltage characteristics and capacitance-voltage characteristics showed the presence of inhomogeneous semiconductor junctions and ohmic contacts in blue LEDs structures that are the source of possible irregularities in the final emission of LED displays. The variation of voltages (at current 10 mA) were 2.81 — 2.98 V for blue structures, and 1.9 — 2.0 V for red ones. Some of the blue structures had additional parasite current-flow mechanism at low current. Rise time and fall time of electroluminescence pulse of blue structures were measured. The shortest LED pulse time in LED displays is limited by duration of 6 — 8 ns. The quality of LED displays may be improved by implementating the preliminary control of LED chips in a narrower range of voltage variation at operating currents, or more narrow interval of I—V variation. This additional LEDs sorting will of course reduce the percentage of the total amount of light-emitting diodes, but may improve the image (video, photo) quality at translations by using a lower brightness gradations. |
| format | Article |
| id | doaj-art-d8f0d91b5b5c44c5ac83da54f6669f7a |
| institution | Kabale University |
| issn | 2225-5818 2309-9992 |
| language | English |
| publishDate | 2017-06-01 |
| publisher | Politehperiodika |
| record_format | Article |
| series | Tekhnologiya i Konstruirovanie v Elektronnoi Apparature |
| spelling | doaj-art-d8f0d91b5b5c44c5ac83da54f6669f7a2025-08-20T03:49:13ZengPolitehperiodikaTekhnologiya i Konstruirovanie v Elektronnoi Apparature2225-58182309-99922017-06-013303510.15222/TKEA2017.3.30201Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity gradeV. P. Veleschuk0O. I. Vlasenko1Z. K. Vlasenko2V. V. Shynkarenko3Ya. Ya. Kudryk4P. O. Sai5V. V. Borshch6V. Ye. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, UkraineV. Ye. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, UkraineV. Ye. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, UkraineV. Ye. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, UkraineV. Ye. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, UkraineV. Ye. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, UkrainePoltava National Technical Yuri Kondratyuk University, Poltava, UkraineThe emission uniformity of LED chips in the entire range of brightness and colors is the problem in LED displays manufacture process. It was approved that at lowering brightness gradations appearing the radiation nonuniformity between LED chips, and the higher disorders will be seen on the lesser emission levels. The RGB LED chips, observed by us, were based on AlGaInP (red), In0.3Ga0.7N/GaN (green), and In0,2Ga0,8NN/ GaN (blue) and had nominal working current 20 mA. Analysis of the current-voltage characteristics and capacitance-voltage characteristics showed the presence of inhomogeneous semiconductor junctions and ohmic contacts in blue LEDs structures that are the source of possible irregularities in the final emission of LED displays. The variation of voltages (at current 10 mA) were 2.81 — 2.98 V for blue structures, and 1.9 — 2.0 V for red ones. Some of the blue structures had additional parasite current-flow mechanism at low current. Rise time and fall time of electroluminescence pulse of blue structures were measured. The shortest LED pulse time in LED displays is limited by duration of 6 — 8 ns. The quality of LED displays may be improved by implementating the preliminary control of LED chips in a narrower range of voltage variation at operating currents, or more narrow interval of I—V variation. This additional LEDs sorting will of course reduce the percentage of the total amount of light-emitting diodes, but may improve the image (video, photo) quality at translations by using a lower brightness gradations.https://tkea.com.ua/index.php/journal/article/view/201rgb ledi-v curvesingan/gan |
| spellingShingle | V. P. Veleschuk O. I. Vlasenko Z. K. Vlasenko V. V. Shynkarenko Ya. Ya. Kudryk P. O. Sai V. V. Borshch Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade Tekhnologiya i Konstruirovanie v Elektronnoi Apparature rgb led i-v curves ingan/gan |
| title | Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade |
| title_full | Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade |
| title_fullStr | Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade |
| title_full_unstemmed | Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade |
| title_short | Influence of variation of electrical parameters values of RGB LEDs on the radiation uniformity of LED displays at minimal luminosity grade |
| title_sort | influence of variation of electrical parameters values of rgb leds on the radiation uniformity of led displays at minimal luminosity grade |
| topic | rgb led i-v curves ingan/gan |
| url | https://tkea.com.ua/index.php/journal/article/view/201 |
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