Time to read: 4 min
Light plays an important role in the design of many hardware products. Often, they are both decorative and functional. Indicator lights are the most minimal user interface: They tell you whether the device is turned on, low on battery, or “thinking” really hard.
在现代电子产品上，光的来源几乎总是LED。但是，您很少在设备外部看到裸露的LED组件。你什么dosee is the exit surface of a light pipe (also known as a light guide).
光管可以聚焦，扩散或重定向光；大多数轻型管道可以完成这些组合。
设计注意事项包括：
- 最小化传输过程中的损失
- Minimizing the number of LEDs needed (they are power-hungry components that destroy battery life)
- 最大化RGB LED的颜色混合
在我们的teardowns，我们看到了许多轻型管道 - 它们是我们最喜欢的组件之一，因为每个组件都是如此独特。今天，我们想深入研究一些独特的轻型管应用，并解释每种设计背后的原理。
Application 1: Extending Light’s Reach
As I mentioned, LEDs are power-hungry components. So for portable electronics, you should only use the light when the user is actively interacting with the device, and you’ll want to minimize the number of LEDs needed. Light pipes can be used to extend the reach of LEDs so you can use fewer to achieve the same illumination effect. Here are two examples of how light pipes illuminate logos and thumb pads.
示例1：发光的徽标盔甲不足的心率监测器
The UA heart rate monitor’s front cover features a sizeable logo. The engineers behind this product managed to light up this logo evenly, with just one tiny top-firing LED at the center of the main PCBA. This LED doesn’t have much reach by itself.
Enter the light pipe: It’s made of a milky plastic that could be polycarbonate resin (normally transparent) with addedtitanium二氧化物。添加的二氧化钛越多，塑料越多，可以改善扩散。
光管中心的锥形腔功能旨在匹配LED。锥体的角壁有助于将发光的光引导到光管中。
The cone is the entry point of the light pipe, and the entry point should always be placed as close to the light source as possible, to minimize loss.
Let’s see the actual effect of the light pipe:
- Without the light pipe, there is a strong hot spot in the center of the logo and not much light elsewhere.
- With the light pipe, the light emitted by the LED is spread out more evenly and the extreme hot spot is gone.
示例2：Illuminated Thumb Pad ofLogitech G600 MMO鼠标
The Logitech G600 MMO mouse has a twelve-button thumb pad. Each key is backlit, and the user can customize the light’s color. How many LEDs do you think are used to light up all these keys?
The answer is TWO! Isn’t that surprising? What wizardry!
The secret is side-firing LEDs that emit light directly into a flat plate of a light pipe. Notice how close the entry point of the light pipe is to the LEDs. You can’t afford losses when the lights have a long way to go to their exit points.
请注意，相反的弹性体拇指垫部分如何在某些钥匙上有黑色油漆斑点，而不是其他钥匙？这些黑点接近LED，可能会掩盖热点。
另请注意，轻型管板是超光泽的，并且封装光管的顶部和底部的表面都是白色的。这两种功能都有助于最大程度地提高内部反射并改善颜色混合。
应用2 - 弯曲灯
LED不能总是位于灯光的预期出口后面，因此光管通常用于运输由木板安装的灯输送到距离距离的出口窗口。只要在物理局限性范围内，它们甚至可以“弯曲”光。
这里有一些例子：
Example 1:NeatoLight “Arc”
This light pipe cradles the Neato’s power button. It has two entry points for LEDs to illuminate the entire path evenly. The second LED is needed because light does not like to bend past 90 degrees. If only one LED were used, significant loss would happen where the second entry point is, and the end of the arc would be dark.
光管的入口点很好地匹配LED的形状。
Note that the top surface of the light pipe is textured, whereas all the other surfaces are glossy. Textured surfaces encourage light to exit, and glossy surfaces encourage internal reflection.
Also note that aluminum foil covers the underside of the light pipe. This has two purposes:
- 最大化总内部反思
- To prevent users from seeing internal components underneath the light pipe
示例2：Tivo螺栓状态灯
The TiVo Bolt has five status indicator lights. For all of these, the light source had to be “bent” through light pipes to exit the enclosure.
One of these is a very classic “light pipe,” a clear聚碳酸酯略微弯曲的管从徽标上将光从源传输到出口点。入口点是平坦的表面 - 这是一条尚未与LED匹配的轻型管，会导致亮度损失。但是，这简化了光管的注射模具工具。
The other four indicator lights appear in a row.
This set-up uses a multi-unit light pipe—think of this as a multi-lane roadway! Each “roadway” has its own entry and exit points. The light sources are four surface-mounted LEDs in a row.
轻型管子被两件式黑色裹尸布覆盖，从而消除了光泄漏。由于Tivo螺栓外壳是白色的（不是浅色），因此没有裹尸布，我们将无法清楚地看到每个光线。
主要要点
We hope you enjoyed this “anthology” of light pipe examples. Put your own spin on these established designs, and add some shiny to your next project! Now that you have form factor inspiration, check out ourguide to prototyping light pipes with 3D printing.
