A head mounted display device comprising: a structural frame arranged generally along a X-axis and a Y-axis for viewing along a Z-axis, the X, Y, and Z axes being mutually perpendicular; a micro-display coupled to the structural frame , and configured to project visual content in a substantially forward direction along the Z-axis away from a user; a group of one or more optical elements with reflective optical surfaces coupled to the structural frame and respectively positioned on a front side of the micro-display to reflectively guide a light ray bundle from the micro-display to a user's eye ; and a micro-display alignment mechanism mounted to the structural frame and configured to align and control the reflectively guided light ray bundle from the micro-display to the user's eye by positioning the micro-display along the X and Z axes, wherein the micro-display alignment mechanism comprises: a micro-display holder configured to hold the micro-display ; a carriage configured to couple to and constrain motion of the micro-display holder to motion along the X and Z axes and restraining rotational motion of the micro-display holder to align and control a reflectively guided light ray bundle from the micro-display to a user's eye by positioning the micro-display along the X and Z axes; a X-gear including a user-manipulation portion attached to a shaft configured to be received in a first opening in the carriage; a Z-gear including a user-manipulation portion attached to a shaft configured to be received in a second opening in the carriage, and wherein the micro-display holder includes a tab that is received into a slot in the carriage whereby the tab and slot cooperate to constrain the motion to the X and Z axes. a structural frame arranged generally along a X-axis and a Y-axis for viewing along a Z-axis, the X, Y, and Z axes being mutually perpendicular; a micro-display coupled to the structural frame , and configured to project visual content in a substantially forward direction along the Z-axis away from a user; a group of one or more optical elements with reflective optical surfaces coupled to the structural frame and respectively positioned on a front side of the micro-display to reflectively guide a light ray bundle from the micro-display to a user's eye ; and a micro-display alignment mechanism mounted to the structural frame and configured to align and control the reflectively guided light ray bundle from the micro-display to the user's eye by positioning the micro-display along the X and Z axes, a micro-display holder configured to hold the micro-display ; a carriage configured to couple to and constrain motion of the micro-display holder to motion along the X and Z axes and restraining rotational motion of the micro-display holder to align and control a reflectively guided light ray bundle from the micro-display to a user's eye by positioning the micro-display along the X and Z axes; a X-gear including a user-manipulation portion attached to a shaft configured to be received in a first opening in the carriage; a Z-gear including a user-manipulation portion attached to a shaft configured to be received in a second opening in the carriage, and wherein the micro-display holder includes a tab that is received into a slot in the carriage whereby the tab and slot cooperate to constrain the motion to the X and Z axes. <EOS>