AppleInsider spotted a patent granted to Apple published in the US Patent and Trademark Office (USPTO) indicating this. As optical switches, the keyboard will be using light emitters and sensors. Key presses are registered when the key itself is pressed down, blocking the light from reaching the sensor. This is similar to the way the new Razer Viper‘s optical switches work.
Another implementation has the sensor detect change in the amount of light hitting the sensor, rather than just if the light is blocked. This could then be used to set an “actuation” point that registers the key press. Since it’s not an actual switch, it may be possible to change this “actuation” point so that the keys require a lighter or a deeper press. All that said, the upcoming MacBook may still end up using the scissor switches as previously reported. Patents don’t always end up in products after all, but being pleasantly surprised by the presence of optical switches isn’t exactly a bad thing. (Source: USPTO via AppleInsider)