US 7,538,757 B2
Temperature dependent electrophoretic preset pulse
Guofu Zhou, Best (Netherlands); and Mark T. Johnson, Veldhoven (Netherlands)
Assigned to Koninklijke Philips Electronics N.V., Eindhoven (Netherlands)
Appl. No. 10/557,683
PCT Filed May 17, 2004, PCT No. PCT/IB2004/001700
§ 371(c)(1), (2), (4) Date Nov. 22, 2005,
PCT Pub. No. WO2004/104977, PCT Pub. Date Dec. 02, 2004.
Claims priority of provisional application 60/473208, filed on May 23, 2003.
Prior Publication US 2007/0052665 A1, Mar. 08, 2007
Int. Cl. G09G 3/34 (2006.01)
U.S. Cl. 345—107  [359/296] 32 Claims
OG exemplary drawing
 
1. A display device comprising electrophoretic particles, a temperature sensor, a processor and a display element comprising two or more electrodes, the processor applying a driving pulse and a pre-pulse to one of said electrodes,
a portion of the electrophoretic particles being present between the electrodes,
the driving pulse being set to bring the display element to a predetermined optical state corresponding to image information to be displayed,
the temperature sensor being configured to detect a temperature of the display device and transmit a temperature input corresponding to the detected temperature to the processor,
the pre-pulse preceding the driving pulse and comprising one or more preset pulses, each said preset pulse transmitting an energy to the portion of the electrophoretic particles sufficient to release all or part of the portion of electrophoretic particles from a first position near one of said electrodes,
said energy being too low to enable said all or part of the particles to reach a second position near the other one of said electrodes,
the first position corresponding to a first optical state, the second position corresponding to a second optical state, and
the processor increasing volt-milliseconds of relative potential difference applied by the preset pulse with respect to potential difference applied by the driving pulse, in response to an increase in the detected temperature.