Back to results
US 5,986,640 AGranted
Display device using time division modulation to display grey scale
AssigneeDigital Projection Limited
InventorsJohn Lewis Edwin Baldwin, Brian Eckersley
Life of this patent
Estimating the term…
Abstract
A display device includes a deformable mirror device wherein grey scales are displayed using a time division modulation process in which the times or sub-frame periods for which each mirror within the deformable mirror array is switched on. The device includes a selection means for ordering selected sub-frame periods or divided sub-frame periods such that the light directed from each mirror is substantially temporally balanced during each frame period of the display device and/or between consecutive frame periods.
Claims20
A display device comprising:
- (a) an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) means for providing a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit on each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) means for switching each pixel element "ON" in each image frame for time periods corresponding to said total "ON" time periods;
- and
- (d) means for re-ordering said "ON" time period such that the "ON" time periods for a pixel element in each image frame are in a sequence which differs from the order of the bits in the number corresponding to the pixel element, said re-ordering being such that any difference in the temporal distribution of the "ON" time periods for each pixel in successive frame intervals is less than the difference which would arise if said "ON" time periods were not re-ordered.
2 more elements
A method of addressing a display device comprising an array of pixel elements each switchable between an "ON" state and an "OFF" state comprising the steps of:
- (a) providing a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (b) switching each pixel element "ON" in each image frame for time periods corresponding to said total "ON" time periods;
- and
- (c) re-ordering said "ON" time periods such that the "ON" time periods for a pixel element in each image frame are in a sequence which differs from the order of the bits in the number corresponding to the pixel element, said re-ordering being such that any difference in the temporal distribution of the total "ON" time periods for each pixel in successive frame intervals is less than the difference which would arise if said "ON" time periods were not re-ordered.
1 more element
A display system comprising:
- (a) a display device comprising an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) means for providing a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) means for switching each pixel element "ON" in each image frame for time periods corresponding to said total "ON" time periods;
- (d) means for re-ordering said "ON" time periods such that the "ON" time periods for a pixel element in each image frame are in a sequence which differs from the order of the bits in the number corresponding to the pixel element, said re-ordering being such that any difference in the temporal distribution of the "ON" time periods for each pixel in successive frame intervals is less than the difference which would arise if said "ON" time periods were not re-ordered, and
- (e) a display screen, the display device being effective to project successive image frames onto the display screen.
2 more elements
A display device comprising:
- (a) an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) means for providing a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) means for switching each pixel element "ON" in each image frame for time periods corresponding to said "ON" time periods;
- and
- (d) means for dividing at least one of said plurality of different "ON" time periods into at least two sub-periods effective to switch said one pixel element "ON" during time intervals which are temporally spaced apart from each other, such that any differences in at least one of the temporal distribution between successive frame intervals and the temporal distribution between adjacent pixel elements are less than the differences which would arise if said "ON" time period was not divided.
2 more elements
A method of addressing a display device comprising an array of pixel elements each switchable between an "ON" state and an "OFF" state comprising the steps of:
- (a) providing a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (b) switching each pixel element "ON" in each image frame for time periods corresponding to said "ON" time periods;
- and
- (c) dividing at least one of said plurality of different "ON" time periods into at least two sub-periods effective to switch said one pixel element "ON" during time intervals which are temporally spaced apart from each other, such that any differences in at least one of the temporal distribution between successive frame intervals and the temporal distribution between adjacent pixel elements are less than the differences which would arise if said "ON" time period was not divided.
1 more element
A display system comprising:
- (a) a display device comprising an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) means for providing a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) means for switching each pixel element "ON" in each image frame for time periods corresponding to said "ON" time periods;
- (d) means for dividing at least one of said plurality of different "ON" time periods into at least two sub-periods effective to switch said one pixel element "ON" during time intervals which are temporally spaced apart from each other, such that any differences in at least one of the temporal distribution between successive frame intervals and the temporal distribution between adjacent pixel elements are less than the differences which would arise if said "ON" time period was not divided;
- and
- (e) a display screen, the display device being effective to project successive image frames onto the display screen.
3 more elements
A display device comprising:
- (a) an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) a signal providing circuit arranged to provide a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit on each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) a switching circuit arranged to switch each pixel element "ON" in each image frame for time periods corresponding to said total "ON" time periods;
- and
- (d) a reordering circuit arranged to re-order said "ON" time period such that the "ON" time periods for a pixel element in each image frame are in a sequence which differs from the order of the bits in the number corresponding to the pixel element, said re-ordering being such that any difference in the temporal distribution of the "ON" time periods for each pixel in successive frame intervals is less than the difference which would arise if said "ON" time periods were not re-ordered.
2 more elements
A display system comprising:
- (a) a display device comprising an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) a signal providing circuit arranged to provide a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) a switching circuit arranged to switch each pixel element "ON" in each image frame for time periods corresponding to said total "ON" time periods;
- (d) a re-ordering circuit arranged to reorder said "ON" time periods for a pixel element in each image frame are in a sequence which differs from the order of the bits in the number corresponding to the pixel element, said re-ordering being such that any difference in the temporal distribution of the "ON" time periods for each pixel in successive frame intervals is less than the difference which would arise if said "ON" time periods were not re-ordered;
- and
- (e) a display screen, the display device being effective to project successive image frames onto the display screen.
3 more elements
A display device comprising:
- (a) an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) a signal providing circuit arranged to provide a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) a switching circuit arranged to switch each pixel element "ON" in each image frame for time periods corresponding to said "ON" time periods;
- and
- (d) a re-ordering circuit arranged to divide at least one of said plurality of different "ON" time periods into at least two sub-periods effective to switch said one pixel element "ON" during time intervals which are temporally spaced apart from each other, such that any differences in at least one of the temporal distribution between successive frame intervals and the temporal distribution between adjacent pixel elements are less than the differences which would arise if said "ON" time period was not divided.
2 more elements
A display system comprising:
- (a) a display device comprising an array of pixel elements each switchable between an "ON" state and an "OFF" state;
- (b) a signal providing circuit arranged to provide a succession of image signals each representative of successive image frames, each said image signal representing a plurality of numbers each comprising a plurality of bits, each number corresponding to a different pixel element in each image frame, each bit of each said number defining one of a plurality of different "ON" time periods for one of the pixel elements so that each number represents the total "ON" time period for a different one of the pixel elements in each image frame;
- (c) a switching circuit arranged to switch each pixel element "ON" in each image frame for time periods corresponding to said "ON" time periods;
- (d) a re-ordering circuit arranged to divide at least one of said plurality of different "ON" time periods into at least two sub-periods effective to switch said one pixel element "ON" during time intervals which are temporally spaced apart from each other, such that any differences in at least one of the temporal distribution between successive frame intervals and the temporal distribution between adjacent pixel elements are less than the differences which would arise if said "ON" time period was not divided;
- and
- (e) a display screen, the display device being effective to project successive image frames onto the display screen.
3 more elements
Dependencies are inferred from the claim text.