A head mounted display apparatus, comprising: a display, receiving an augmented reality image (ARIMG) and an external image (RIMG), and sending a display image, being the augmented reality image (ARIMG) and/or the external image (RIMG), along a projection direction, the display being one of a diffractive grating waveguide, a multilayer film polarized reflection waveguide, a semi-transflective optical layer, and a free-form optical layer; an optical converter, disposed at a first side of, and separate from, the display, and receiving the display image from the display and changing an emitting angle of the display image to send an output image to a target region; an optical shutter, disposed at a second side, opposite the first side, of the display, and configured to shield a transmission path between the external image (RIMG) and the display; and an optical engine, sending the augmented reality image (ARIMG) to the display, characterized in that the optical shutter is configured to open the transmission path during a first time interval, and shield the transmission path during a second time interval; the first time interval is longer than the second time interval; a first brightness of the augmented reality image (ARIMG) provided by the optical engine during the first time interval is smaller than a second brightness of the augmented reality image (ARIMG) provided by the optical engine during the second time interval; and wherein in the first time interval, the display is configured to combine the augmented reality image (ARIMG) and the external image (RIMG) to generate the display image; in the second time interval, the display is configured to only transmit the augmented reality image (ARIMG) to generate the display image; and wherein a time length ratio of the first time interval and the second time interval is N:1, N is a positive integer greater than 1, a frame period comprises N+1 sub-frame periods, a time length of the first time interval is equal to N sub-frame periods, a time length of the second time interval is equal to one sub-frame period, and a ratio of the second brightness and the first brightness is N:1. a display, receiving an augmented reality image (ARIMG) and an external image (RIMG), and sending a display image, being the augmented reality image (ARIMG) and/or the external image (RIMG), along a projection direction, the display being one of a diffractive grating waveguide, a multilayer film polarized reflection waveguide, a semi-transflective optical layer, and a free-form optical layer; an optical converter, disposed at a first side of, and separate from, the display, and receiving the display image from the display and changing an emitting angle of the display image to send an output image to a target region; an optical shutter, disposed at a second side, opposite the first side, of the display, and configured to shield a transmission path between the external image (RIMG) and the display; and an optical engine, sending the augmented reality image (ARIMG) to the display, characterized in that the optical shutter is configured to open the transmission path during a first time interval, and shield the transmission path during a second time interval; the first time interval is longer than the second time interval; a first brightness of the augmented reality image (ARIMG) provided by the optical engine during the first time interval is smaller than a second brightness of the augmented reality image (ARIMG) provided by the optical engine during the second time interval; and wherein in the first time interval, the display is configured to combine the augmented reality image (ARIMG) and the external image (RIMG) to generate the display image; in the second time interval, the display is configured to only transmit the augmented reality image (ARIMG) to generate the display image; and wherein a time length ratio of the first time interval and the second time interval is N:1, N is a positive integer greater than 1, a frame period comprises N+1 sub-frame periods, a time length of the first time interval is equal to N sub-frame periods, a time length of the second time interval is equal to one sub-frame period, and a ratio of the second brightness and the first brightness is N:1.