US Patent No. 9,086,614

PROJECTION DISPLAY APPARATUS AND CONTROL METHOD THEREFOR


Patent No. 9,086,614
Issue Date July 21, 2015
Title Projection Display Apparatus And Control Method Therefor
Inventorship Yukinori Shioya, Tokyo (JP)
Hiroki Tanaka, Tokyo (JP)
Kenji Kanzaka, Tokyo (JP)
Michio Kobayashi, Tokyo (JP)
Assignee NEC DISPLAY SOLUTIONS, LTD., Tokyo (JP)

Claim of US Patent No. 9,086,614

1. A projection display apparatus projecting image light based on an image signal, comprising:
a lamp;
a display element that modulates light emitted from said lamp according to an amplitude of the image signal, and that emits
the light as the image light;

a light intensity controller that changes a lamp power according to a power changing operation that is input from an outside
so as to change the lamp power for driving said lamp, and, if the changed lamp power is lower than a rated power of said lamp
and supplied to said lamp for at least a certain period of time, generates a control signal for causing a lamp refreshing
process to be performed that increases the lamp power to the rated power and then reduces the lamp power to an original power
after elapse of a predetermined period of time, identifies an amplitude value of the image signal where an intensity of the
image light is constant before and after the change of the lamp power in said lamp refreshing process, and generates a control
signal for changing the amplitude of the image signal to the identified amplitude value;

a ballast that drives said lamp and performs said lamp refreshing process according to the control signal, that causes said
lamp refreshing process to be performed and that is generated by said light intensity controller; and

an image signal controller that controls the amplitude of the image signal according to the control signal, that causes the
amplitude of the image signal to be changed and that is generated by the light intensity controller, and supplies the image
signal whose amplitude is controlled to said display element.