Head-mountable devices can include a light projection display element that is directly coupled to an assembly that includes a waveguide. Such a direct coupling can be achieved by bonding the light projection display element directly to a lens or other optical component that is, in turn, directly coupled to the waveguide. Such an optical module can be assembled outside of the head-mountable device for precision alignment and subsequently installed as an integrated unit. These measures can help maintain component alignment while allowing a head-mountable device to be lightweight and small in size.