Video projection device and video projection method

A video projection device comprising:

• a laser light source unit which is configured to emit a laser;
• a laser scanning unit which is provided with one or more scanning directions and is configured to project video by performing a reciprocating scan of the laser with respect to a scanning direction with a highest scanning frequency at a predetermined scanning cycle;
• and
• a control unit which is configured to control operations of the laser light source unit and the laser scanning unit depending on a video signal, so that, with respect to the scanning direction along which the reciprocating scan is performed, a time difference between a time when emission of the laser in an outgoing path is stopped and a time when emission of the laser in a return path is started is longer than half an interval between adjacent pulses of the laser when the adjacent pulses are treated as a single pulse,
• wherein the predetermined scanning cycle is longer than the time difference ×2/(1−a rate R), where an upper limit of an output of the laser is reduced by the rate R at a turnaround position of the reciprocating scan when the adjacent pulses of the laser are treated as a single pulse.

A video projection device comprising:

• a laser light source unit which is configured to emit a laser;
• a laser scanning unit which is provided with one or more scanning directions and is configured to project video by performing a reciprocating scan of the laser with respect to a scanning direction with a highest scanning frequency;
• and
• a control unit which is configured to control operations of the laser light source unit and the laser scanning unit depending on a video signal, so that a period during which the laser is emitted and a period during which emission of the laser is stopped are repeated alternately, and a period during which the emission of the laser is continuously stopped is longer than a period corresponding to an angle that is necessary for the laser scanning unit to scan a range corresponding to the size of an eye along the scanning direction with the highest scanning frequency at a position apart therefrom by a distance with which the eye is in focus.