In an image projection on a screen, an image projection apparatus improves the safety of entry into a projection region by the human body and does not bring about the increase of complexity of the configuration thereof owing to the improvement of the safety. A monitoring area is regulated on the outside of the projection area (3) of the screen (2). A detection wave such as infrared rays is emitted from a detection wave source (1c) of the image projection apparatus (1). A reflection wave from the monitoring area is detected by reflection wave detection means (1d) such as a CCD sensor. Whether the human body or an obstacle enters the monitoring space, which is surrounded by a detection wave (4) between the main body unit of the image projection apparatus (1) and the screen (2), or not is detected. Once the entry is detected, the intensity of the radiation light traveling toward the projection area (3) is reduced or cut off according to the situation or the degree of the entry.
The present invention generally relates to a dynamic aperture for controlling the intensity of light of projection lens, more particularly to a dynamic aperture driving apparatus and method for reducing vibration by which vibrations are minimized in spite of command for sudden location change. The dynamic aperture driving apparatus comprises rotating means, driving means, sensing means and driving control means, whereas a location control signal is characterized by minimizing vibration when the rotating means arrives at a commanded location by an increase in rising time and/or falling time of a target location signal through an RC integral circuit within the driving control means.
