Televizyonların Arka Işık Sistemlerinde Kullanılan LED Fosfor Teknolojilerinin Güvenirlik ve Renk Doğruluğu Üzerine Etkileri
Abstract
LED’lerde kullanılan fosfor tabakaları mavi renkte ışıma yapan bir LED çipin beyaz tonlarında ışıma yapmasını sağlamaktadır. Sektörde başlıca YAG (Yttrium Aluminum Garnet) ve KSF (K2SiF6:Mn4+) olmak üzere iki çeşit fosfor türü kullanılmaktadır. Kullanılan bu fosforlar farklı renk yelpazesi sunabilmektedir ancak bunun yanında farklı dayanım özelliklerine de sahiptirler. Bu çalışmada, televizyonlarda kullanılan YAG ve KSF fosforlu LED’lerden oluşan LED barlar farklı ortam koşulları ve sürme akımlarında çalıştırılarak güvenirlik açısından incelenmiştir. Birinci durumda ortam sıcaklığı yüksek tutulurken düşük LED akımı uygulanmış, ikinci durumda ise düşük ortam sıcaklığında yüksek LED akımı uygulanmıştır. Her iki durumda da test öncesi ve test sonrası her bir LED’in mikroskop görüntüleri alınmıştır. Ayrıca her durumda LED’ler periyodik olarak kontrol edilerek LED’lerin jonksiyon sıcaklıkları kaydedilmiştir. Kontrol sırasında LED’lerin testin kaçıncı saatinde bozulduğu kayıt altına alınarak Reliasoft programında güvenilirlik analizi yapılmış ve yaklaşık ömürleri tahmin edilmiştir. Böylece fosfor türlerinin LED’lerin dayanımına olan etkisi karşılaştırılmıştır.
Keywords
LED Televizyon Fosfor Teknolojisi Televizyon Arka Işık Sistemi Güvenirlik Analizi Jonksiyon Sıcaklığı
Supporting Institution
Arçelik A.Ş., Yıldız Teknik Üniversitesi Bilimsel Araştırma Projeleri Koordinatörlüğü
Project Number
FYL-2023-5681
Thanks
Yazarlar, Arçelik A.Ş. ve Yıldız Teknik Üniversitesi Bilimsel Araştırma Projeleri Koordinatörlüğü'ne (YTUBAPK-FYL-2023-5681) bu çalışma süresince sağladıkları destek için teşekkür eder.
References
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- K. Kakinuma, “Technology of wide color gamut backlight with light-emitting diode for liquid crystal display television,” Jpn. J. Appl. Phys., vol. 45, no. 5B, pp. 4330–4334, 2006.
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- Y. Shimizu, K. Sakano, Y. Noguchi, and T. Moriguchi, “5,998,925,” U.S. Patent, 1999.
- G. Blasse and A. Bril, “Appl. Phys. Lett.,” vol. 11, pp. 53–55, 1967.
- S. Adachi and T. Takahashi, “Direct synthesis and properties of K2SiF64+ phosphor by wet chemical etching of Si wafer,” J. Appl. Phys., vol. 104, no. 2, 2008.
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- Reliasoft Weibull ++7, “Reliasolft Publishing”, Tuson, Arizona USA.
Effects of LED Phosphor Technologies Used in Television Backlight Systems on Reliability and Color Accuracy
Abstract
Phosphor layers used in LEDs enable a blue-emitting LED chip to emit light in white tones. Two primary types of phosphors are used in the industry, YAG (Yttrium Aluminum Garnet) and KSF (K2SiF6+). These phosphors offer different color spectrums while also possessing varying durability characteristics. This study examines LED bars composed of LEDs with YAG and KSF phosphors, commonly used in televisions, for reliability under different environmental conditions and driving currents. The ambient temperature is kept high in the first scenario while applying a low LED current. In the second scenario, a low ambient temperature with a high LED current is applied. Microscopic images of each LED are taken both before and after the tests in both scenarios. Additionally, during the tests, periodic checks are conducted to record the junction temperatures of the LEDs. The point at which each LED failed is documented, and reliability analysis is performed using the Reliasoft program to estimate their approximate lifetimes. Thus, the impact of phosphor types on the durability of LEDs is compared.
Keywords
LED Television Phosphor Technology Television Backlight System Reliability Analysis Junction Temperature
Project Number
FYL-2023-5681
References
- K. Kakinuma, T. Matsumoto, S. Haga, T. Arai, T. Shirakuma, and H. Shibata, “The first LED backlight for LCD TVs to increase color reproduction range”, Nikkei Electronics pp. 123–130, 2004.
- K. Kakinuma, “Technology of wide color gamut backlight with light-emitting diode for liquid crystal display television,” Jpn. J. Appl. Phys., vol. 45, no. 5B, pp. 4330–4334, 2006.
- J.W. Stinson, “4,992,704,” U.S. Patent 1991.
- S. Tabuchi, “S50–79379,“ Japanese Utility Model Patent Application Publication, 1973.
- Y. Shimizu, “H07–176794,“ Japanese Publication of Unexamined Patent Application, 1995.
- Y. Shimizu, “H08–7614,“ Japanese Patent Application Publication, 1996.
- Y. Shimizu, K. Sakano, Y. Noguchi, and T. Moriguchi, “5,998,925,” Japanese priority patent applications to U.S. Patent, 1996.
- Y. Shimizu, K. Sakano, Y. Noguchi, and T. Moriguchi, “5,998,925,” U.S. Patent, 1999.
- G. Blasse and A. Bril, “Appl. Phys. Lett.,” vol. 11, pp. 53–55, 1967.
- S. Adachi and T. Takahashi, “Direct synthesis and properties of K2SiF64+ phosphor by wet chemical etching of Si wafer,” J. Appl. Phys., vol. 104, no. 2, 2008.
- H.F. Sijbom, R. Verstraete, J.J. Joos, D. Poelman, and P. F. Smet, “K2SiF6:Mn4+ as a red phosphor for displays and warm-white LEDs: A review of properties and perspectives,” pp. 3332–3365, 2017.
- [12] A.L. Efros, “Interband absorption of light in a semiconductor sphere,” Soviet Physics Semiconductors, vol. 16, no. 7, pp. 772–775, 1982.
- AV Technology, “Sony's Breakthrough with Quantum Dots at CES 2013” Retrieved from https://av.technology. [Access Date: 20/09/2024]
- Y. H. Ko and J. G. Park, “Novel quantum dot enhancement film with a super-wide color gamut for LCD displays,” Journal of the Korean Physical Society, vol. 72, pp. 45–51, 2018.
- J. E. Murphy, F. Garcia-Santamaria, A. A. Setlur, and S. Sista, “ 62.4: PFS K2SiF6:Mn4+: the Red-line Emitting LED Phosphor behind GE's TriGain Technology™ Platform“, in Book 2: Session 62: Advanced Light Sources, Components, and Systems II, 2015.
- Rtings “TV Picture quality tests:Color Gamut” url: https://www.rtings.com/tv/tests/picture-quality/wide-color-gamut-rec-709-dci-p3-rec-2020. [Access Date: 01/02/2024].
- BENQ “What is color gamut” https://www.benq.com/en-us/knowledge-center/knowledge/color-gamut-monitor.html. [Access Date: 01/02/2024]
- CIE,“Commission internationale de l'Eclairage proceedings”, Cambridge: Cambridge University Press, 1931.
- National Television System Committee Report and Reports of Panel No. 11, 11-A, 12–19, “with Some supplementary references cited in the Reports, and the Petition for adoption of transmission standards for color television before the Federal Communications Commission”, LC Control No.:54021386 Library of Congress Online Catalog,1951–1953.
- IEC TS 60079-43, “Technıcal Specıfıcatıon Explosive atmospheres – Part 43: Equipment in adverse service conditions”, 2017.
- Reliasoft Weibull ++7, “Reliasolft Publishing”, Tuson, Arizona USA.
Details
| Primary Language | Turkish |
|---|---|
| Subjects | Lighting |
| Journal Section | Research Articles |
| Authors | |
| Project Number | FYL-2023-5681 |
| Early Pub Date | October 25, 2024 |
| Publication Date | October 29, 2024 |
| Submission Date | September 19, 2024 |
| Acceptance Date | October 12, 2024 |
| Published in Issue | Year 2024 Volume: 6 Issue: 2 |
