Patent ID: 6462721
Filing Date: 2002-10-08
Classification: G09G

Abstract:
A drive pulse controller for creating a driving signal for a display device in order to display images such that a gradation display is produced, each field of an input image signal, corresponding to a plurality of pixels, being divided into a plurality of Z weighted subfields, each field having a constant period, the drive pulse controller comprising:a device that determines a number of subfields Z for each field of the input image signal; a picture signal-subfield corresponding device that changes the input image signal into a Z-bit brightness signal; a pulse number setting device that specifies a number of sustain pulses for each subfield within a field; a subfield processor that creates a driving signal for each field based on the Z-bit brightness signal and the number of sustain pulses; a time data source that stores light emission time data in association with different Z values, the light emission time data being indicative of a time at which a most-weighted subfield, which has the largest number of sustain pulses of all subfields in a field, is positioned within the field; a selecting device that selects one of the light emission time data stored in the time data source based on the determined number of subfields Z; a calculating device that calculates a delay time for positioning the host-weighted subfield at a predetermined time in a field based on the selected light emission time data, such that the most-weighted subfields of consecutive fields having different numbers of subfields Z are positioned substantially at a same time; and a delay device that delays the driving signal in accordance with the calculated delay time.