US Patent 10162185 Head-mounted display and brightness control method

In a head-mounted display for presenting a video by shielding an outside world from a field of view of a user when mounted on the user, an information presentation block presents information including audio and a moving image to the field of view of the user; a video reproduction block reproduces a video of content; a camera takes a video of the outside world; a switching block selectively switches between the video of the content and the video of the outside world and causes the selected video to be presented onto the information presentation block; and a gain control block, when the switching block switches from the video of the content to the video of the outside world, gradually increases a brightness of the video of the outside world.