Use get_stylesheet_directory_uri or get_template_directory_uri to return the URI of the theme directory. The former will return the child theme directory, in the event a child theme is being used. The latter will always be the main or parent theme in the case where a child theme is active.
Also, note that “path” typically refers to what you get back from get_theme_root(). It’s the location local to the server, and is not the same thing as a URI / URL.