Answer: He cannot receive a patent since he is merely making the sunglasses more portable.
Explanation: Patent refers to the right granted to the inventor of a product, machine or equipment such that others are excluded from making, using, selling or importing such product which is adapted for use of the patent.
Felix cannot receive a patent on his invention because he only made a portable version of a preexisting invention. Patents are granted to products which are new, useful and non-obvious.