Look at the ridiculous level of detail Apple takes to make sure the letters on its keyboards can be seen in the dark

Flickr/ CJ Sorg

The keys on your Mac glow in the dark. Simple enough right? Not really.

Apple goes to a ridiculous amount of trouble to make sure the keys on its keyboards glow to just the right extent.

One of Apple's patents, filed back in 2013, shows how this works. 

To start with, there's a keycap with a partially or fully transparent covering. Then, the first layer of opaque coating is put on top. A second layer is then put on top of the first:.

It looks like this:

United States Patent and Trademark Office

After that, at least the first layer of coating is etched off part of the key, so light can come through.

  

United States Patent and Trademark Office

But then – this is the important part – a portion of the first etched area is etched off to a second depth to create a second etched area:

United States Patent and Trademark Office

This means that the section that has a larger depth etched away – down through the second layer of the key's coating – can transmit more light than the section of the key which only has the first layer etched away.

This can create a few different effects, the document explains. For example, a keycap may be etched away to form a graphic or letter, with the outer portion etched deeper to create a brighter border.

United States Patent and Trademark Office

So, why has Apple filed a patent for this? It's only etching, after all — a process that has been used in manufacturing for centuries.

A clue comes in Apple's background statement of purpose for the patent. The company says it is obsessed with making everything ever-so-slightly better:

... there is always a desire to provide new and improved designs or techniques that result in even more aesthetically pleasing graphics.