ヘッドマウントディスプレイ（HMD）

A head-mounted display (or helmet-mounted display, for aviation applications), both abbreviated HMD, is a display device, worn（着用、装着）on the head or as part of a helmet, that has a small display optic in front of one (monocular HMD) or each eye (binocular HMD). (Wikipedia, "Head-mounted display")

US8625200
Abstract
"Head-mounted displays (100)（＊複数形）are disclosed（開示）which include a frame (107), an image display system (110) supported by the frame (107), and a reflective surface, e.g., a free-space, ultra-wide angle, reflective optical surface (a FS/UWA/RO surface) (120), supported by the frame (107). In certain embodiments, the reflective surface (120) produces spatially-separated virtual images that are angularly separated by at least 100, 150, or 200 degrees. Methods and apparatus for designing reflective optical surfaces, including FS/UWA/RO surfaces, for use in head-mounted displays (100) are also disclosed."

"A head-mounted display such as a helmet-mounted display or eyeglass-mounted display (abbreviated herein as（略称）a “HMD”) is a display device worn（着用、装着）on the head of an individual that（＊先行詞はdisplay device）has one or more small display devices located near one eye or, more commonly, both eyes of the user. FIG. 1 shows the basic elements of one type of HMD which includes a display 11, a reflective optical surface 13, and an eye 15 having a center of rotation 17. As shown in this figure（図）, light 19 from display 11 （無冠詞）is reflected by surface 13 and enters（入射）the user's eye 15."

"Some HMDs display only simulated (computer-generated) images, as opposed to（対して、異なり、ではなく、対照的）real-world images, and accordingly（従って）are often referred to as "virtual reality" or immersive HMDs. Other HMDs superimpose（重ね合わせ、重畳）(combine) a simulated image upon a non-simulated, real-world image. The combination of non-simulated and simulated images allows the HMD user to view the world through, for example, a visor or eyepiece on which additional data relevant to（関連）the task to be performed is superimposed onto the forward field of view (FOV) of the user. This superposition is sometimes referred to as "augmented reality" or "mixed reality.""

"Combining（結合）a non-simulated, real-world view with a simulated image can be achieved using（＊by無し）a partially-reflective/partially-transmissive optical surface (a "beam splitter") where（＊＝whereby, so that, such that...?  詳細な説明の付加）the surface's reflectivity is used to display the simulated image as a virtual image (in the optical sense) and the surface's transmissivity is used to allow the user to view the real world directly (referred to as an "optical see-through（透視）system"). Combining a real-world view with a simulated image can also be done electronically by accepting video（＊無冠詞）of a real world view from a camera and mixing it electronically with a simulated image using a combiner (referred to as a "video see-through system"). The combined image can then be presented to the user as a virtual image (in the optical sense) by means of（により）a reflective optical surface, which in this case need not have transmissive properties."