Patent ID: 9104059
Filing Date: 2015-08-11
Classification: G02F,G03B

Abstract:
1. An image display device that has a light source and that displays an image composed of a plurality of pixels obtained by spatially modulating light emitted from said light source corresponding to an input image signal, said image display device comprising: a power supply section that supplies power to said light source; a cooling fan that cools said light source; a drive section that drives said cooling fan; an image determination section that determines whether said input image signal represents a bright image or a dark image based on luminance values of the pixels of said image supplied as said input image signal; and a control section that controls said drive section to drive said cooling fan and said power supply section to supply power to said light source, wherein if said image determination section determines that said input image signal represents a bright image, said control section sets up a first lighting mode in which an output of said power supply portion is a first power value and if said image determination section determines that said input image signal represents a dark image, said control section sets up a second lighting mode in which the output of said power supply section is a second power value that is less than said first power value, wherein said control section stores a first table that contains data representing a relationship between the power value of said power supply section and a number of rotations of said cooling fan in a case in which the output of said power supply section is increased from said second power value to said first power value at a constant rate and when said second lighting mode is switched to said first lighting mode, said control section increases the output of said power supply section to said first power value at a constant rate and controls the rotation of said cooling fan corresponding to the power value of said power supply section with reference to said first table, wherein said control section stores a second table that contains data representing the relationship between the power value of said power supply section and the number of rotations of said cooling fan in the case in which the output of said power supply section is decreased from said first power value to said second power value at a constant rate and when said first lighting mode is switched to said second lighting mode, said control section decreases the output of said power supply section to said second power value at a constant rate and controls the rotation of said cooling fan corresponding to the power value of said power supply section with reference to said second table, and wherein said control section stores a first setup value that is set up in said first lighting mode as the number of rotations of said cooling fan and controls the rotation of said cooling fan with reference to said first table such that, before the output of said power supply section becomes said first power value, said control section increases the number of rotations of said cooling fan to the number of rotations that is greater than said first setup value at a constant rate and then decreases the number of rotations of said cooling fan to the number of rotations corresponding to said first setup value, said image display device further comprising: