Tag: led

利用 Smart TV 監控的技術也成熟了...

透過 WikiLeaks 公開出來的文件得知 CIA 與 MI5 都已經有能力將後門埋入 Samsung 的 Smart TV 內：「The CIA Spied on People Through Their Smart TVs, Leaked Documents Reveal」。

Hackers at the Central Intelligence Agency, with the help of colleagues from the British spy agency MI5, developed malware to secretly spy on targets through their Samsung Smart TVs, according to new documents published by WikiLeaks.

這個後門在 Fake-Off 模式中仍然可以繼續運作：

The malware was designed to keep the smart TVs on even when they were turned off. This was dubbed "Fake-Off mode," according to the documents.

甚至可以控制 LED 燈，讓被監控人無法得知現在 Smart TV 其實還在運作中：

The CIA hackers even developed a way to "suppress" the TVs LED indicators to improve the "Fake-Off" mode.

突然想到該找時間複習 1984，裡面描述的概念現在在生活週邊愈來愈多了...

LED 燈泡的壽命

在「What Happened to the 100,000-Hour LED Bulbs?」這邊看到在討論 LED 燈泡的壽命。比較感興趣的是到底業界怎麼計算 LED 燈泡的壽命。

前面提到很多因使用時間的增加而產生衰退與色偏，然後講到「壽命」的定義是，超過一半的燈泡低於 70% 的原始亮度所需要的時間：

Research says that most users won’t notice a gradual 30% drop in light levels; accordingly the industry has defined L70, the time at which the output has dropped to 70% of its initial level, as an endpoint for measuring LED bulb lifetime. Based on how it’s estimated, this measure is typically stated as B50-L70, the point at which 50% of an initial sample of bulbs will retain 70% of their rated output.

另外一個有趣的資料是，LED 燈泡故障的原因中，電源供應相關佔了最大的比率 (過半)：

算是個有趣的知識...