US Patent No. 10,542,240

PROJECTOR AND METHOD FOR CONTROLLING ROTATION OF PHOSPHOR WHEEL AND COLOR WHEEL IN PROJECTOR


Patent No. 10,542,240
Issue Date January 21, 2020
Title Projector And Method For Controlling Rotation Of Phosphor Wheel And Color Wheel In Projector
Inventorship Masayuki Murakami, Tokyo (JP)
Assignee NEC DISPLAY SOLUTIONS, LTD., Tokyo (JP)

Claim of US Patent No. 10,542,240

1. A projector comprising:a phosphor wheel that is configured to be rotatable and in which a phosphor and a mirror and a first mark are formed around a rotational axis, said phosphor wheel both emitting fluorescence realized by said phosphor and excitation light realized by said mirror in a time series when irradiated by excitation light and supplying a first reference signal realized by said first mark for each rotation;
a color wheel that rotates in synchronization with said phosphor wheel and in which a specific region that is irradiated by said excitation light and a plurality of regions that are irradiated by said fluorescence and a second mark are formed around a rotational axis, said color wheel both emitting a plurality of illumination light beams being emitted from said specific region and said plurality of regions in a time series and supplying a second reference signal realized by said second mark for each rotation;
a Digital Micromirror Device (DMD) that modulates said plurality of illumination light beams emitted by said color wheel; and
a control unit that both controls a modulation operation of said DMD according to illumination light that is irradiated upon the DMD and, at the time of switching the modulation operation of a predetermined color, controls the rotation operation of said phosphor wheel and said color wheel on the basis of said first reference signal and second reference signal such that said excitation light is irradiated in said specific region;
wherein:
said control unit causes said DMD to display an image in which gradations change in steps; changes the input timings of said first reference signal and said second reference signal a plurality of times to measure color coordinate values of each gradation; and controls the rotation operation of said phosphor wheel and said color wheel on the basis of the coordinate values of each gradation that are measured for every time that the input timings change.