My question is regarding improvement patents. I have read some literature online, but it's all still pretty convoluted regarding this issue of improvement patents. My question is how does building your technology on top of already existing (and most likely patented) technology work. For example: computer mouses at one time all used wires to attach to the computers and send signals back to the computer and one day I came along and decided that I was going to remove the wire and instead use wireless tech. (Bluetooth, WIFI, w/e the details are irrelevant). How do I determine whether my new technology is patentable and does not infringe on the existing technology that is probably patented itself?
There are two separate issues here that are very frequently conflated. Your ability to get a patent has nothing to do with what others have or have not patented per se. It has to do with what others have done and allowed public access to. Your invention will be looked at in comparison with previous publications to judge the novelty and non-obviousness of your idea. The previous publications can be patents, expired patents, patent applications that were totally rejected, magazine articles, etc. A large % of issued patents would be considered improvement patents. If you search for issued patents on manual tooth brushes you will find a vast array of attempts to improve on the basic tooth brush.
The first wireless mouse may have been non-obvious altogether or maybe the inventor had to create a special protocol or other technology for the mouse to be low power enough or maybe some inventing needed to be done to bring the cost down to the point it was practical to put wireless in a low cost device.
The second issue is - if you made your invention would it infringe on an existing patent for the underlying base technology? If someone had a patent on the optical mouse, your wireless optical mouse might very well infringe. That doesn't mean you can't get a patent, it means you can't make it or sell it.