An eyepiece for a head mounted display, the eyepiece comprising: an illumination module for providing computer generated image ("CGI") light along a forward propagation path within the eyepiece; a concave end reflector disposed at an opposite end of the eyepiece from the illumination module to reflect the CGI light back along a reverse propagation path within the eyepiece; a viewing region to be aligned with an eye of a user, the viewing region disposed between the illumination module and the concave end reflector and including an out-coupling polarizing beam splitter ("PBS" 260), the out-coupling PBS to pass the CGI light traveling along the forward propagation path and to redirect the CGI light traveling along the reverse propagation path out of an eye-ward side of the eyepiece; and a polarization rotator disposed in the forward and reverse propagation paths of the CGI light between the out-coupling PBS and the concave end reflector; wherein the illumination module comprises: a physical block including an in-coupling PBS, which is separated from; a lamp disposed adjacent to the physical block that includes the in-coupling PBS to direct illumination light onto the in-coupling PBS; a display disposed opposing the concave end reflector with the physical block that includes the in-coupling PBS in between such that the in-coupling PBS redirects the illumination light from the lamp onto the display and the display reflects the illumination light as the CGI light along the forward propagation path through the in-coupling PBS; and a diffusion surface, disposed on at least one side surface of the physical block which opposes and faces the lamp with the in-coupling PBS in between the diffusion surface and the lamp, to inhibit total internal reflections off the at least one side surface of the physical block to impede unwanted reflections originating at the display from propagating down the eyepiece from the illumination module to the viewing region. an illumination module for providing computer generated image ("CGI") light along a forward propagation path within the eyepiece; a concave end reflector disposed at an opposite end of the eyepiece from the illumination module to reflect the CGI light back along a reverse propagation path within the eyepiece; a viewing region to be aligned with an eye of a user, the viewing region disposed between the illumination module and the concave end reflector and including an out-coupling polarizing beam splitter ("PBS" 260), the out-coupling PBS to pass the CGI light traveling along the forward propagation path and to redirect the CGI light traveling along the reverse propagation path out of an eye-ward side of the eyepiece; and a polarization rotator disposed in the forward and reverse propagation paths of the CGI light between the out-coupling PBS and the concave end reflector; wherein the illumination module comprises: a physical block including an in-coupling PBS, which is separated from; a lamp disposed adjacent to the physical block that includes the in-coupling PBS to direct illumination light onto the in-coupling PBS; a display disposed opposing the concave end reflector with the physical block that includes the in-coupling PBS in between such that the in-coupling PBS redirects the illumination light from the lamp onto the display and the display reflects the illumination light as the CGI light along the forward propagation path through the in-coupling PBS; and a diffusion surface, disposed on at least one side surface of the physical block which opposes and faces the lamp with the in-coupling PBS in between the diffusion surface and the lamp, to inhibit total internal reflections off the at least one side surface of the physical block to impede unwanted reflections originating at the display from propagating down the eyepiece from the illumination module to the viewing region. a physical block including an in-coupling PBS, which is separated from; a lamp disposed adjacent to the physical block that includes the in-coupling PBS to direct illumination light onto the in-coupling PBS; a display disposed opposing the concave end reflector with the physical block that includes the in-coupling PBS in between such that the in-coupling PBS redirects the illumination light from the lamp onto the display and the display reflects the illumination light as the CGI light along the forward propagation path through the in-coupling PBS; and a diffusion surface, disposed on at least one side surface of the physical block which opposes and faces the lamp with the in-coupling PBS in between the diffusion surface and the lamp, to inhibit total internal reflections off the at least one side surface of the physical block to impede unwanted reflections originating at the display from propagating down the eyepiece from the illumination module to the viewing region.