What is The part of the eye that converts light energy to electricity into electricity signals?

First you must understand how light is transferred into an image by the eye. Located in the retina at the back of the eye are millions of photoreceptors. The way I understand them to work is they are constantly blocking any impules from themselves to the next connection, ganglions. When light hits these potoreceptors, the impulse is released, travels through the ganglion, and then is transmitted to the actual optic nerve.

So according to this question, the photoreceptors are the trigger of light to impulse, but the answer to your question is the ganglion that transmitts the impulse to the optic nerve.