Explaining Hall-effect, TMR, and other new types of “mechanical” switches

解析霍尔效应、TMR 及其他新型“机械”轴体

The mechanical keyboard isn’t always so mechanical anymore. Over the past six years, keyboards with optical, Hall-effect, and other “contactless” switches have become increasingly common, often going for higher prices than traditional mechanical keyboards, which already command a premium over basic membrane boards. In return, they promise some theoretical advantages, particularly for gamers. In daily use, though, the differences can be pretty subtle. So what exactly are you paying for? In this guide, we break down how the newest switches work, why contactless designs are becoming more popular, and where their advantages—and disadvantages—really matter.

机械键盘如今已不再那么“纯粹”了。在过去的六年里，搭载光学、霍尔效应以及其他“非接触式”轴体的键盘变得越来越普遍。它们的价格通常高于传统的机械键盘，而后者本身就已经比基础的薄膜键盘贵出不少。作为回报，这些新型轴体提供了一些理论上的优势，尤其是对于游戏玩家而言。然而在日常使用中，这些差异可能相当细微。那么，你到底在为这些溢价买单什么呢？在本指南中，我们将剖析这些最新轴体的工作原理、非接触式设计为何日益流行，以及它们的优缺点究竟在何处体现。

How standard mechanical switches work

标准机械轴体的工作原理

First, let’s recap what happens when you push a key with a traditional mechanical switch inside. As you can see in the diagram of a Cherry MX Brown switch below, standard mechanical switches have two metal leaves—in this case, the “crosspoint”—that are shaped differently, with the top of the larger leaf bent away from the smaller leaf.

首先，让我们回顾一下当你按下传统机械轴体时会发生什么。正如你在下方 Cherry MX 茶轴的示意图中所见，标准机械轴体拥有两片金属簧片（在此处称为“交叉点”），它们的形状各异，较大簧片的顶部会向远离较小簧片的方向弯曲。

When you press a mechanical switch, its plastic stem moves downward toward the keyboard’s PCB, and a spring wrapped around the stem compresses. As you release the button, the spring expands, forcing the stem back up to its original position. When a switch is at rest, a protruding piece of the plastic stem keeps the switch’s two leaves from making contact. As the stem goes downward, that piece moves with it, allowing the leaves to touch and close a circuit on the keyboard’s PCB, which sends a signal to the keyboard’s microcontroller, telling the computer which input was made.

当你按下机械轴体时，其塑料轴心会向下移动至键盘的 PCB 板，包裹在轴心周围的弹簧随之压缩。当你松开按键时，弹簧回弹，迫使轴心回到初始位置。当轴体处于静止状态时，轴心上的一块凸起部分会阻隔两片金属簧片接触。随着轴心向下移动，该凸起部分随之移开，使簧片得以接触并闭合 PCB 上的电路，从而向键盘的微控制器发送信号，告知计算机触发了哪个输入。

But because mechanical switches rely on the physical contact of internal components, they can degrade over time. 但由于机械轴体依赖内部组件的物理接触，它们会随着时间的推移而产生磨损。

Why new switches?

为什么要使用新型轴体？

The switches in this guide, however, differ from traditional mechanical switches because they don’t register input through contact between two metal leaves—hence the term “contactless.” Manufacturers often claim contactless switches last longer than regular switches, and they’re not susceptible to oxidation or corrosion, which can affect mechanical switches after prolonged use.

然而，本指南中的轴体与传统机械轴体不同，因为它们不是通过两片金属簧片的接触来记录输入的——因此被称为“非接触式”。制造商通常声称，非接触式轴体比普通轴体寿命更长，且不易受到氧化或腐蚀的影响，而这些问题在长期使用后可能会影响机械轴体。

But there are other things to keep in mind for longevity. Contactless switches require specific PCBs, which are less common than those used for standard mechanical switches. And while hot-swappability can extend a keyboard’s life by making it easier to replace a broken key or change switches, hot-swappable PCBs for contactless switches—and prebuilt keyboards that support contactless switches and hot-swapping—are harder to find. Newer standard mechanical switches, including some Cherry MX2A-series switches rated for 100 million keystrokes, can have lifespans similar to those of contactless options. If longevity is a priority, contactless switches may still be worth considering, but be sure to compare their ratings with those of standard switches.

但关于使用寿命，还有其他因素需要考虑。非接触式轴体需要特定的 PCB 板，这比标准机械轴体所用的 PCB 更为少见。虽然热插拔功能可以通过更轻松地更换损坏的按键或轴体来延长键盘寿命，但支持非接触式轴体的热插拔 PCB，以及支持非接触式轴体且具备热插拔功能的成品键盘，都更难寻觅。较新的标准机械轴体（包括一些额定寿命达 1 亿次敲击的 Cherry MX2A 系列轴体）也可以拥有与非接触式轴体相当的寿命。如果寿命是你的首要考虑因素，非接触式轴体仍然值得考虑，但请务必将其额定寿命与标准轴体进行对比。

Some users and companies claim that contactless switches feel smoother when pressed and reset because no metallic leaves touch. But other parts of the switch, like the spring and stem, can also create friction. I’ve occasionally noticed smoother presses with certain contactless switches (more on that later), but some premium standard switches, especially properly lubricated ones, can also feel extremely smooth. If you want the best-feeling switches, look beyond whether they operate mechanically or through light beams or magnets. Factors like the switch’s specs, force curve, and materials can have a greater impact on how a switch feels.

一些用户和厂商声称，由于没有金属簧片接触，非接触式轴体在按下和回弹时手感更顺滑。但轴体的其他部分，如弹簧和轴心，也会产生摩擦。我偶尔会发现某些非接触式轴体的按压感更顺滑（稍后会详细说明），但一些高端的标准轴体，尤其是经过妥善润滑的，也能提供极佳的顺滑感。如果你追求最佳的手感，不要仅仅纠结于它是通过机械接触、光束还是磁铁来运作的。轴体的规格、压力曲线和材质等因素，对轴体手感的影响往往更大。

Customizable actuation

可自定义触发点

Many contactless switches have customizable actuation points, a feature that isn’t possible with traditional mechanical switches. That can be helpful if you want some keys to feel stiffer or lighter than others (I prefer a stiffer spacebar, for instance), more flexibility over how keys respond, or analog input. But software may not accurately reflect a switch’s actual actuation point. Review website RTINGs tested 14 keyboards with adjustable actuation from 11 brands and found that, on each keyboard, the keys actuated at a different distance than the one set in the companion app. We’re talking about differences of fractions of a millimeter, but it’s worth keeping in mind if you’re considering contactless switches for customizable actuation.

许多非接触式轴体具有可自定义的触发点，这是传统机械轴体无法实现的功能。如果你希望某些按键的手感比其他按键更硬或更轻（例如，我更喜欢硬一点的空格键），或者需要更灵活的按键响应及模拟输入，这会非常有帮助。但软件可能无法准确反映轴体的实际触发点。评测网站 RTINGs 测试了来自 11 个品牌的 14 款具备可调触发功能的键盘，发现每款键盘的实际触发距离都与配套应用程序中设置的数值存在偏差。虽然偏差仅在毫米级，但如果你是为了自定义触发点而考虑非接触式轴体，这一点值得注意。

Some keyboards with contactless switches go further by letting users program keys so that one full press results in two inputs. For example, you can set a key to input “A” if you press it down 0.5 mm and then “B” if you press it down another 0.5 mm. Some keyboards with contactless switches also support analog input, which lets the keyboard detect how far a switch has been pressed and adjust the input accordingly, giving gamers a joystick-like experience. Traditional mechanical keyboards don’t support analog input.

一些搭载非接触式轴体的键盘更进一步，允许用户编程按键，实现“一键双触发”。例如，你可以设置按键在按下 0.5 毫米时输入“A”，继续按下 0.5 毫米时输入“B”。一些非接触式轴体键盘还支持模拟输入，这使得键盘能够检测轴体被按下的深度并相应地调整输入，为游戏玩家提供类似操纵杆的体验。传统的机械键盘不支持模拟输入。

Gaming advantages

游戏优势

Contactless switches are becoming more common largely because of their potential appeal to gamers. Vendors often claim keyboards with contactless switches register input faster than traditional mechanical keyboards, mostly because the switches don’t require debouncing.

非接触式轴体变得越来越普遍，很大程度上是因为它们对游戏玩家具有潜在的吸引力。厂商通常声称，搭载非接触式轴体的键盘比传统机械键盘记录输入的速度更快，这主要是因为这些轴体不需要去抖动（debouncing）。