Image projection apparatus having shutter mechanism for hiding projection image

An image projection apparatus comprising:

• an optical modulation element;
• a projection lens configured to project light modulated by the optical modulation element onto a projection surface;
• an optical unit configured to guide light from a light source to the optical modulation element and to guide the light from the optical modulation element to the projection lens;
• a shutter mechanism disposed between the optical unit and the projection lens and configured to operate so as to be in an open state and a closed state;
• and
• a focus corrector configured to correct a focus variation generated by temperature changes of the optical unit and the projection lens by operating the projection lens based on a focus correction function,
• wherein the focus corrector sets a first saturated focus variation amount and a second saturated focus variation amount, the first saturated focus variation amount being a focus variation amount which is saturated when the light source is turned on and the shutter mechanism is an open state, and the second saturated focus variation amount being a focus variation amount which is saturated when the light source is turned on and the shutter mechanism is in a closed state, and
• wherein the focus corrector changes the focus correction function so that the focus variation amount is gradually equal to the first saturated focus variation amount when the light source is turned on and the shutter mechanism is an open state, and changes the focus correction function so that the focus variation amount is gradually equal to the second saturated focus variation amount when the light source is turned on and the shutter unit is in a closed state.