that it is possible to transmit a video

視頻可以由一個LED檯燈

from a standard off-the-shelf LED lamp

傳送到太陽能面板上，

to a solar cell with a laptop acting as a receiver.

並由一台筆記型電腦播放出來。

There is no Wi-Fi involved, it's just light.

這當中沒有Wi-Fi 介入，只有光。

And you may wonder, what's the point?

而你可能會想， 這樣做有甚麼意義嗎？

And the point is this:

意義就是：

There will be a massive extension of the Internet

網際網路即將會大規模的延伸，

to close the digital divide,

進而結束「數位落差」現象。

and also to allow for what we call "The Internet of Things" --

並且連上我們所謂的「物聯網」——

tens of billions of devices connected to the Internet.

數十億的網路連結設備。

In my view, such an extension of the Internet can only work

在我看來，這樣的網路延伸情況

if it's almost energy-neutral.

只能在「中性能源 」(低耗能) 的情況下才能運作，

This means we need to use existing infrastructure as much as possible.

意思就是，我們需要盡可能 使用現存的基礎設施。

And this is where the solar cell and the LED come in.

所以這也是為什麼要有 太陽能面板與LED燈的參與。

I demonstrated for the first time,

我第一次展示是在

at TED in 2011,

2011年的TED演講上。

Li-Fi, or Light Fidelity.

Li-Fi 簡稱「光保真」或者「光頻網路」

Li-Fi uses off-the-shelf LEDs to transmit data incredibly fast,

Li-Fi 利用現成的LED， 以驚人的速度傳送數據，

and also in a safe and secure manner.

而且是以安全隱密的方式傳輸。

Data is transported by the light,

數據藉由光傳輸，

encoded in subtle changes of the brightness.

以細微的亮度變化來編碼。

If we look around, we have many LEDs around us,

如果我們環顧四周， 在我們身邊有很多的LED燈，

so there's a rich infrastructure of Li-Fi transmitters around us.

所以我們周圍有足夠的Li-Fi傳送設備。

But so far, we have been using special devices -- small photo detectors,

但目前為止，我們還在使用一種 特殊設備--「小型照片偵測器」

to receive the information encoded in the data.

來接收數據裡編碼的資訊，

I wanted to find a way to also use existing infrastructure

我想找到一種方法， 利用現存的基礎設施

to receive data from our Li-Fi lights.

從Li-Fi燈來獲取數據，

And this is why I have been looking into solar cells and solar panels.

這也是為什麼我一直研究 太陽能面板與太陽能控制板的原因。

A solar cell absorbs light and converts it into electrical energy.

太陽能面板吸收光源 並把它轉換成電力。

This is why we can use a solar cell to charge our mobile phone.

這也是為什麼我們可以利用 太陽能面板來為我們的手機充電，

But now we need to remember

但現在，我們需要記住，

that the data is encoded in subtle changes of the brightness of the LED,

數據是被微小變化的LED光源所編碼，

so if the incoming light fluctuates,

所以如果入射的光源有波動，

so does the energy harvested from the solar cell.

從太陽能面板收集來的能量也會有波動。

This means we have a principal mechanism in place

這意思就是，我們有一個 主要的運作機制：

to receive information from the light and by the solar cell,

資訊透過光的傳導，由太陽能面板來接收，

because the fluctuations of the energy harvested

因為收集的能量波動

correspond to the data transmitted.

與傳輸的數據相對應。

Of course the question is:

當然問題就在：

can we receive very fast and subtle changes of the brightness,

我們是否能夠收集到 非常迅速和微小的亮度變化，

such as the ones transmitted by our LED lights?

比如通過我們的LED燈 傳遞的那種方式一樣?

And the answer to that is yes, we can.

答案是：是的，我們可以。

We have shown in the lab

我們已經在實驗室裡證實，

that we can receive up to 50 megabytes per second

我們可以透過一個 標準現有的太陽能面板，

from a standard, off-the-shelf solar cell.

每秒接收到50MB的數據，

And this is faster than most broadband connections these days.

這比現今大部分的寬頻還要快。

Now let me show you in practice.

現在，讓我實際操作給各位看，

In this box is a standard, off-the-shelf LED lamp.

在這盒子裡是一個 標準的、買來就可以用的LED燈，

This is a standard, off-the-shelf solar cell;

這個是標準現成的太陽能面板，

it is connected to the laptop.

它連結到筆記型電腦上，

And also we have an instrument here

我們這裡也有一個儀器，

to visualize the energy we harvest from the solar cell.

用來觀測我們從太陽能面板 收集到的能源。

And this instrument shows something at the moment.

儀器目前顯示有些狀況發生，

This is because the solar cell already harvests light from the ambient light.

這是因為太陽能面板已經 收集到周圍環境的光源，

Now what I would like to do first is switch on the light,

現在我首先要做的是打開光源，

and I'll simply, only switch on the light,

只是簡單地開燈，

for a moment,

等一段時間....

and what you'll notice is that the instrument jumps to the right.

你會注意到儀器指針跑到右邊，

So the solar cell, for a moment,

所以這個太陽能面板

is harvesting energy from this artificial light source.

目前正在從這個人工光源收集能源。

If I turn it off, we see it drops.

如果把它關掉，我們可以看到， 指針往下掉

I turn it on ...

再打開...

So we harvest energy with the solar cell.

我們就能從太陽能面板上收集到能源，

But next I would like to activate the streaming of the video.

但接下來，我要啟動視頻播放。

And I've done this by pressing this button.

我已經設定好按下此按鈕即可，

So now this LED lamp here is streaming a video

所以現在這個LED燈

by changing the brightness of the LED in a very subtle way,

正透過亮度的細微變化 來傳輸一個視頻，

and in a way that you can't recognize with your eye,

一種你無法用肉眼辨識的方式傳輸，

because the changes are too fast to recognize.

因為變的太快以致於你無法辨識。

But in order to prove the point,

但為了證明這一點，

I can block the light of the solar cell.

我可以擋住整個太陽能面板的光源，

So first you notice the energy harvesting drops

所以你可以看到，能量收集下降，

and the video stops as well.

視頻也跟著停止，

If I remove the blockage, the video will restart.

如果我移開檔板，視頻就會重新開始。

(Applause)

(掌聲)

And I can repeat that.

我可以再重複一遍。

So we stop the transmission of the video and energy harvesting stops as well.

我們停止影片的傳送， 能量收集也跟著停止，

So that is to show that the solar cell acts as a receiver.

這可以證實，太陽能面板 扮演了接收器的角色。

But now imagine that this LED lamp is a street light, and there's fog.

但是現在想像一下， 這個LED燈是街燈，然後起霧了。

And so I want to simulate fog,

我來模擬一下起霧時的情況，

and that's why I brought a handkerchief with me.

這也是為什麼我要 隨身攜帶手帕的原因。

(Laughter)

（笑聲）

And let me put the handkerchief over the solar cell.

讓我把手帕放在太陽能面板上，

First you notice

首先你會注意到，

the energy harvested drops, as expected,

能量收集如預期的下降了，

but now the video still continues.

但現在視頻仍在播放，

This means, despite the blockage,

意思就是，儘管有阻礙物，

there's sufficient light coming through the handkerchief to the solar cell,

只要有足夠的光源穿過 手帕傳到太陽能面板，

so that the solar cell is able to decode and stream that information,

太陽能面板就可以編碼 並傳輸資訊，

in this case, a high-definition video.

就像這個範例，一個高解析度視頻。

What's really important here is that a solar cell has become a receiver

重要的是，太陽能面板 變成一個接收的介面，

for high-speed wireless signals encoded in light,

接收了光源的高速無線訊號編碼，

while it maintains its primary function as an energy-harvesting device.

同時也保持了它原本作為 能源收集設備的基本功能。

That's why it is possible

這也是為什麼，

to use existing solar cells on the roof of a hut

我們可以利用屋頂上的太陽能面板

to act as a broadband receiver

作為寬頻網路的接收器，

from a laser station on a close by hill, or indeed, lamp post.

無論是從附近山坡上的 雷射光塔或是街邊的路燈。

And It really doesn't matter where the beam hits the solar cell.

從哪裡來的光束傳到 太陽能面板並不要緊。

And the same is true

並且實際上，

for translucent solar cells integrated into windows,

窗戶上安裝的半透明太陽能面板、

solar cells integrated into street furniture,

安裝在街邊設施的太陽能面板、

or indeed, solar cells integrated into these billions of devices

甚至是安裝到這數十億個 設備的太陽能面板，

that will form the Internet of Things.

它們將會形成物聯網 。

Because simply,

因為簡單來說，

we don't want to charge these devices regularly,

我們不想經常給這些設備充電，

or worse, replace the batteries every few months.

更不想每幾個月就要更換電池

As I said to you,

我之前向各位說明，

this is the first time I've shown this in public.

這是我第一次在公眾場合展示，

It's very much a lab demonstration,

這像是一個實驗室發表會，

a prototype.

一個範例原型，

But my team and I are confident that we can take this to market

但我的團隊與我都有信心，

within the next two to three years.

在未來的2~3年， 我們這項產品會進入市場，

And we hope we will be able to contribute to closing the digital divide,

而且我們都希望我們可以為 「數位落差」現象做出貢獻，

and also contribute

並且對串聯這些

to connecting all these billions of devices to the Internet.

數十億個設備到網絡做出貢獻。

And all of this without causing

而且所有設備都不會造成

a massive explosion of energy consumption --

一個巨大的能源消耗 --

because of the solar cells, quite the opposite.

因為太陽能面板是 相當環保節能的。

Thank you.

謝謝各位。

(Applause)

(掌聲)