| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection video display apparatus which, in using a light source in which a fluorescent substance is made to emit light by excitation light, improves a lifetime of the light source with the fluorescent substance without causing an increase in size of the apparatus.SOLUTION: A projection video display apparatus includes: an excitation light source group for emitting excitation light; a base material on which a fluorescent substance for emitting fluorescent light by incidence of the excitation light is applied; a first light intensity detector for detecting the intensity of the excitation light; a second light intensity detector for detecting the intensity of the fluorescent light; a control device for determining whether or not to move the base material on the basis of a detection value of the first and the second light intensity detectors; and a moving device for moving the base material in accordance with an indication of the control device. When the ratio of a decrease in the intensity of the fluorescent light to a decrease in the intensity of the excitation light exceeds a prescribed value, the control device may give the indication to the moving device so as to move the base material. Furthermore, the control device may move the base material in the direction orthogonal to the direction of the incident light axis in which the excitation light is incident on the base material. |
