Optical system for a lighting device

An lighting device assembly comprising:

• a light generation module comprising an emitter assembly, wherein the emitter assembly comprises an array of emitters configured to emit light, the array of emitters characterized by an area that is centered about a central axis of the light generation module;
• and
• an optical structure comprising a body having a light-entry portion configured to receive the light emitted by the emitters, a light-exit portion, and a side wall extending between the light-entry portion and the light-exit portion, the body centered about the central axis of the light generation module, the side wall defining a total internal reflection (TIR) surface within the body of the optical structure, the TIR surface configured to reflect light emitted by the emitter assembly towards the light-exit portion;
• wherein the light-exit portion comprises a front surface and a well formed into the front surface, the well comprising a center surface surrounded by a beveled portion that is configured to refract light that is reflected off of the TIR surface towards the central axis of the light generation module, such that light rays that are transmitted from the light-exit portion are substantially collimated, and wherein the well defines an opening in the front surface of the light-exit portion, the opening comprises four long sides, wherein each of the long sides is straight and parallel to a respective side of the array of the emitters.