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2018-09-23 / [管理員]

2018創新發明館-技術推薦系列報導(1) 低眩光白光LED

新聞內容:

「具低眩光特性之偏極化白光LED封裝技術」除可以增強偏極化白光LED的發光效率與偏極性,同時因為將具奈米結構的金屬線柵偏光器面朝下,放置在黃色螢光層上方,以保護該奈米金屬線柵偏光層免於受損,且可增加偏極化白光LED產品對環境忍受度與量產之可行性。

蘇忠傑副教授指出,眩光可分為光幕、反射、直接等三類,但共同的成因都是由於亮度太高或對比強烈造成,因此目前市面上的照明產品都是將燈具加上經光學設計之霧面、透鏡或燈罩等方式來防止眩光,而這些防眩光方法卻使得光源亮度降低,有浪費能源的潛憂。

而運用此一新技術的偏極化白光LED光源則具有低眩光、顏色穩定、發光均勻、高極化率、透光率高、色溫低、高對比、製程簡單及生產成本低等優點,一改傳統非偏極光的白光LED光源所具有的發光不均勻、色溫偏高、眩光強烈造成刺眼無法直視、影像模糊並造成辨識困難等問題。

蘇忠傑副教授表示,理想白光照明要求的是足夠亮度、發光顏色可調與視覺舒適,而舒適代表著光源無眩光。室內外照明使用偏極化白光LED時,如檯燈、交通號誌燈、路燈、體育場與醫療照明,可提高物體識別度及對人眼舒適度。偏極化光源對於拍攝物體的影像可增加對比度及解析度,例如應用於閃光燈、顯微鏡與自動化檢測之光源時,可減少反光以增加物體影像的清晰度。此外,偏極化LED光源更可作為液晶顯示器用之背光源模組。

「此技術無須改變傳統白光LED製程,量產成本增幅小,並降低了外加燈罩或透鏡的需求,將為白光LED的應用帶來新的突破,因此已順利取得台灣、美國、中國專利。」蘇忠傑副教授表示,偏極化LED如果應用於車燈,將使頭燈光會使對向來車的駕駛增加舒適度,增加夜間駕駛對路況辨識度。未來甚至可提升自動駕駛之影像偵測的安全性。


Since the glare effect will cause decreased vision, fatigue, and dizziness for the driver, traffic accidents are frequently resulted from under a long term glare condition. Dr. Jung-Chieh Su, an associate professor of the Department of Electronic Engineering at National Taiwan University of Science and Technology, proposed an innovative packaging structure for white light-emitting diodes (LEDs) pumped by blue light LEDs, which combines traditional unpolarized white LEDs with commercially available polymeric reflective polarizers. This technique of producing polarized white light is used to reduce the glare caused by traditional unpolarized white light sources, and induce comfortable vision for human eye as if wearing anti-glare lenses or polarized sunglasses.


Because the nanowire grid polarizer is placed face down above the yellow phosphor resin layer layer, the nanowire grid polarizing layer is protected from damage to increase the environmental durability. Hence, "Low glare polarized white LED packaging technology " can enhance not only the luminous efficiency and the polarization ratio, but also the feasibility of mass production.

Associate Professor Su Jung-Chieh pointed out that glares can be divided into three categories: veiling, reflective and direct glares, caused by excess brightness or strong contrast. Therefore, the lighting products on the market are always implemented with optical elements such as diffuser, lens or lampshade to reduce glare. However, these anti-glare methods reduce the glares with decreased brightness and electrical energy is wasted.


Comparing to the conventional white LED, which is with non-uniform luminous pattern, excess color temperature, strong glare resulted in blurred image and visual recognition difficulty, the merits of polarized white LED light source are with low glare, stable emission color, uniform luminous distribution, high polarization ratio, high transmittance, lower color temperature, high contrast, simple manufacturing process and low production cost.


Associate Professor Su Jung-Chieh said that ideal illumination source requires sufficient brightness, tunable color and visual comfort, while comfort means that the light source is with glare-free. By implementing with polarized white LEDs, indoor and outdoor lighting, such as desk lamps, traffic lights, street lights, stadiums and medical lighting, can improve visual recognition and comfort for human eye. The polarized light source can increase the contrast and resolution of the image of the object. For example, when a polarized light source is used for a flash light, a microscope, and an automated optical inspection, the diffusive scattering of light can be reduced to increase the sharpness of the image of the object. In addition, the polarized LED light source can also be used as a backlight source for liquid crystal display without back polarizers.


"This technology does not need to change the traditional white LED manufacturing process, the increased cost in mass production is small, and the need for additional lampshades or lenses will be omitted, which will pave the way for the new industrial application of white LEDs. Therefore, Taiwan, the United States, and China patents have been granted." Associate Professor Su Jung-Chieh said that for the application in the automobile lighting, the polarized headlights will increase the comfort of driver’s vision to the incoming vehicle and increase the visual recognition of the road conditions during night driving. In the future, the reliability of image recognition for autopilot can be enhanced.

新聞連絡人: 國立臺灣科技大學-蘇忠傑 副教授

連絡資訊: 02-27301231