Projection display apparatus and control method therefor
A projection display apparatus includes: a display element that displays an image; a lamp that illuminates the display element to cause the display element to emit an image light; a variable light intensity element that allows the light emitted from the lamp to pass therethrough, the intensity of light passing through the variable light intensity element being variable; and a light intensity controller that determines whether the display element is at an image mute state in which a full-black image is displayed, or at a normal lighting state other than the image mute state, and when the display element is at the image mute state, reduces the amount of power supplied to the lamp to a level that is lower than that of the normal lighting state to decrease the intensity of light emitted from the lamp, and also decreases the intensity of light that passes through the variable light intensity element.
1. A projection display apparatus projecting an image light based on an image, comprising:
a display element that displays said image;
a lamp that illuminates said display element to cause said display element to emit said image light;
a variable light intensity element that allows the light emitted from said lamp to pass therethrough, the intensity of light passing through the variable light intensity element being variable; and
a light intensity controller that determines whether said display element is at an image mute state in which a full-black image is display, or at a normal lighting state other than said image mute state, and when said display element is at said image mute state, reduces the amount of power supplied to said lamp, and also decreases the intensity of light that passes through said variable light intensity element,
wherein when said light intensity controller detects that said lamp power is smaller than a predetermined value for a certain period of time or longer under said image mute state, said light intensity controller increases the lamp power to said predetermined value, and after elapse of a predetermined period of time, reinstates the lamp power to a value which was prior to the time when the lamp power was increased to said predetermined value, and
wherein a value of said lamp power at a time when said display element is at said image mute state, is lower than a rated power of said lamp.
2. The projection display apparatus according to claim 1 , wherein said variable light intensity element comprises an aperture.
3. The projection display apparatus according to claim 2 , when the display element enters the image mute state, the light intensity controller provides a control signal to the variable light intensity element to make an opening of the aperture smaller than that at the normal lighting state.
4. The projection display apparatus according to claim 1 , wherein said variable light intensity element comprises a liquid crystal element.
5. The projection display apparatus according to claim 1 , wherein when an image signal is not entered, said light intensity controller puts said display element into said image mute state.
6. The projection display apparatus according to claim 1 , wherein the predetermined value is a percentage of the normal lighting state of the lamp.
7. A control method of a projection display apparatus including a display element that displays an image, a lamp that illuminates said display element to cause said display element to emit an image light, a variable light intensity element that allows the light emitted from said lamp to pass therethrough, the intensity of light passing through said variable light intensity element being variable,
wherein a light intensity controller determines whether said display element is at an image mute state in which a full-black image is displayed, or at a normal lighting state other than said image mute state, and when said display element is at said image mute state, reduces the amount of power supplied to said lamp, and also decreases the intensity of light that passes through said variable light intensity element,
wherein when said light intensity controller detects that said lamp power is lower than a predetermined value for a certain period of time or longer under said image mute state, said light intensity controller increases the lamp power to said predetermined value, and after elapse of a predetermined period of time, reinstates the lamp power to a value which was prior to the time when the lamp power was increased to said predetermined value, and
wherein a value of said lamp power at a time when said display element is at said image mute state, is lower than a rated power of said lamp.
8. The control method of a projection display apparatus according to claim 7 , wherein when an image signal is not entered, said light intensity controller puts said display element into said image mute state.
9. The control method of a projection display apparatus according to claim 7 , wherein the predetermined value is a percentage of the normal lighting state of the lamp.
10. The control method of a projection display apparatus according to claim 7 , further comprising making an opening of an aperture of the variable light intensity element smaller than that at the normal lighting state when the display element enters the image mute state.