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US 12,469,471 B2Granted
Pulse width modulation for phase-modulating display
OwnerIan Kyles, Howard V. Goetzinventors
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Abstract
A method is disclosed for controlling a liquid crystal pulse width modulated display. A repetition period includes A group periods, each including B modulation intervals, each modulation interval spanning H unit durations and, except for the final modulation interval of the repetition period, a remainder unit duration. A desired number N of unit duration pulses are distributed into H unit duration pulses for each modulation interval, with remainder desired pulses distributed among the remainder unit durations of the modulation intervals. A drive sequence is generated, including one or more repetitions of the repetition period.
Claims20
A method for controlling a liquid crystal pulse width modulated display, the method comprising:
- determining a desired number N of pulses of a unit duration over a repetition period, the repetition period consisting of:
- a first number A of group periods;
- each group period consisting of a second number B of modulation intervals;
- and
- each modulation interval comprising a third number (C−1) of unit durations followed by, for each modulation interval except a final modulation interval of a final group period, an additional unit duration;
- such that the repetition period spans (A×B×C)−1 unit durations;
- determining a group period baseline number of pulses D equal to an integer quotient of a Euclidean division of N by A;
- determining a modulation interval baseline number of pulses H equal to an integer quotient of a Euclidean division of D by B;
- determining a main segment modulation interval pattern consisting of H unit duration pulses at the first H unit durations of each modulation interval;
- determining a repetition period remainder L2 equal to the integer remainder of the Euclidean division of N by A;
- determining a group period remainder L equal to the integer remainder of the Euclidean division of D by B;
- determining a baseline group period pattern consisting of:
- the main segment modulation interval pattern applied to each modulation interval of the group period;
- and
- an additional L unit duration pulses allocated to a unit duration following the first H unit durations of each of L modulation intervals selected from the group period;
- and
- determining a repetition sequence for the repetition period consisting of:
- the baseline group period pattern repeated for each group period of the repetition period;
- and
- an additional L2 unit duration pulses allocated to a unit duration following the first H unit durations of a final modulation interval of each of L2 group periods selected from the repetition period;
- and
- generating a drive sequence for controlling the liquid crystal pulse width modulated display, the drive sequence comprising the repetition sequence repeated one or more times.
19 more elements
A system for controlling a liquid crystal pulse width modulated display, comprising a drive sequence generator configured to perform operations including:
- receiving normalized grayscale data representative of a desired number N of unit duration pulses over a repetition period, the repetition period consisting of:
- a first number A of group periods;
- each group period consisting of a second number B of modulation intervals;
- and
- each modulation interval comprising a third number (C−1) of unit durations followed by, for each modulation interval except a final modulation interval of a final group period, an additional unit duration;
- such that the repetition period spans (A×B×C)−1 unit durations;
- determining a group period baseline number of pulses D equal to the integer quotient of the Euclidean division of N by A;
- determining a modulation interval baseline number of pulses H equal to the integer quotient of the Euclidean division of D by B;
- determining a main segment modulation interval pattern consisting of H unit duration pulses at the first H unit durations of each modulation interval;
- determining a repetition period remainder L2 equal to the integer remainder of the Euclidean division of N by A;
- determining a group period remainder L equal to the integer remainder of the Euclidean division of D by B;
- determining a baseline group period pattern consisting of:
- the main segment modulation interval pattern applied to each modulation interval of the group period;
- and
- an additional L unit duration pulses allocated to a unit duration following the first H unit durations of each of L modulation intervals selected from the group period;
- and
- determining a repetition sequence for the repetition period consisting of:
- the baseline group period pattern repeated for each group period of the repetition period;
- and
- an additional L2 unit duration pulses allocated to a unit duration following the first H unit durations of a final modulation interval of each of L2 group periods selected from the repetition period;
- and
- generating a drive sequence for controlling the liquid crystal pulse width modulated display, the drive sequence comprising the repetition sequence repeated one or more times.
19 more elements
Dependencies are inferred from the claim text.