Restrict a library view for document uploader

There are a lot of ways you can achieve this outcome - but it really depends on your outcome goals and security objectives. The easiest way to do this would allow each user to see documents from their own department, but not other departments. For this, you would create a folder per department as well as a security group for each folder and add unique permissions to each folder. The outcome is that the owner and your "see all" users can see everything and each person only sees the documents for their department. Technically, you could create a folder per employee and do the same thing. The reason you want to use folders is that it makes uploading and assigning permissions easier, especially if people will be uploading multiple documents. Another option would be to add a workflow that re-sets the permissions on each document after it is uploaded so that the Created By user can see it + the "see all" users but no one else. That will create an entire library of uniquely permissioned documents and depending on how many documents you have and what process this is supporting, could be another option. If you want to be really creative, Lists have a security setting that allows you to set a toggle that says that each user can only read the items that they have created. If you add the files as attachments to the list, you will get the same outcome - but you won't have the same super-powers that you get if you store the files in a document library.