摘要:
A method of driving an electrophoretic display device, in which at least one voltage pulse is provided in the drive waveform, prior to the drive signal for effecting a desired image transition according to an image to be displayed. The voltage pulse has a polarity and energy which is dependent on, and determined by, a current optical state, irrespective of the next optical state to be acquired by a picture element, and causes the charged particles of an electrophoretic medium to be moved in a direction away from the nearest electrode thereto.
摘要:
An electrophoretic display device comprising charged particles in a fluid between two electrodes. Drive means supply the electrodes with drive waveforms in order to cause the charged particles to occupy a desired optical state according to an image to be displayed. In the case where a pixel is required to remain in the same optical state during an image update sequence, at least one voltage pulse is provided at or near the end of the drive signal to compensate for the effect of crosstalk by drawing the charged particles back to the optical state in which the respective picture element is required to remain during that image update sequence.
摘要:
A method and apparatus for driving an electrophoretic display device with reduced image retention. Image transitions in respect of all pixels are performed during each image update, irrespective of whether the optical state of a pixel is required to change or not. Thus, pixels without substantial optical state change between a first image update period and a subsequent image update period are forced to update during the subsequent image update period. The drive waveforms, in particular those to be applied for updating pixels without substantial optical state change, are preferably configured such that the net DC voltage is substantially zero after every single image transition.
摘要:
An display device (301) has reduced memory (314) requirements for temperature compensation data. A scaling factors (433) for various temperatures and a look-up table for a waveform which is optimized to drive the grayscale for a given display temperature are stored in memory (314). The waveform for a particular temperature of the display (301) is derived from the look-up table and scaling factors (433). At some temperatures, only certain parts of the waveform need be varied, and only these parts require accurate scaling from the look-up table.
摘要:
A system implements a method of activating an electrophoretic display (10). First, the system provides at least one image-dependent data frame (70) including pixel data (72) and a data frame time (74). Second, the system determines a blanking frame (80) including a blanking frame time (84) based on the data frame time. Third, the system addresses the electrophoretic display (10) based on the pixel data (72), the data frame time (74), and the blanking frame (80) to reduce vertical crosstalk.
摘要:
A display device (1) has electrophoretic particles (8, 9), a display element including electrodes (5, 6), between which a portion of the electrophoretic particles (8, 9) is present, a temperature sensor (25) and a processor (15) for supplying a driving pulse (32) to the electrodes (5, 6) to bring the display element to a predetermined black, gray or white state, corresponding to the image information to be displayed. For improved grayscale accuracy and optimal picture and text quality, the processor (15) is further arranged to supply pre-pulses (31) preceding the driving pulses (32). The energy of the pre-pulses (31) is increased with increased temperature measured by the temperature sensor (25) and is sufficient to release the electrophoretic particles at a first position near one of the two electrodes (5, 6), but too low to enable the particles to reach a second position near the other electrode (5 or 6).
摘要:
This invention relates to an electrophoretic display panel (1), for displaying a picture corresponding to image information, comprising a plurality of pixels (2), each containing an amount of an electrophoretic material comprising a first and a second type of particles (6, 7), having mutually different charges, being dispersed in a fluid, a first and a second electrode (8, 9) associated with each pixel (4) for receiving a potential difference as defined by an update drive waveform; and drive means (10), for controlling said update drive waveform of each pixel (4); said update drive waveform comprising a reset portion (R), during which a reset signal is applied over the pixel, and subsequently a driving portion (D), during which a picture potential difference is applied over the pixel for enabling the particles (6, 7) to occupy the position corresponding to the image information. The invention is characterised in that said reset portion (R) of the update drive waveform is configured so that the first and second types of particles (6,7) are brought in close proximity with each other during said reset portion (R) of the update waveform.
摘要:
An image is updated on a bi-stable display (310) such as an electrophoretic display by using voltage waveforms (600, 620, 640, 660; 700, 720, 740, 760; 800, 820, 840, 860) that are configured such that voltage changes are constrained to a subset of possible voltage levels during specific frame times. The specific frame times may occur during datadependent portions of the waveforms, such as a reset portion (R) and/or a drive portion (D, D1, D2). Due to the reduced voltage swing, the supply voltage can be reduced, resulting in reduced power consumption. Moreover, the frame time (FT′) can be shortened during the data-dependent portions of the waveforms to increase the greyscale accuracy and number of grey levels. At other frames times, the voltage levels can vary throughout the full range of possible voltage levels, while a standard frame time (FT) is used.
摘要:
Image quality is improved when updating a display image (310) in a bi-stable electronic reading device (300, 400) such as one using an electrophoretic display, by providing both monochrome and greyscale images. When an update mode of a pixel (2) of the display changes from a monochrome to greyscale, a compensating pulse (805, 825, 845, 865) is applied. The compensating pulse represents an energy based on the energy difference between: (a) an over-reset pulse (815, 835, 855, 875) used during the greyscale update mode and (b) a standard reset pulse (610, 660) used during the monochrome update mode. Also, a monochrome update waveform (600, 650) includes a standard reset pulse (610, 660) whose duration is substantially less than a duration of an over-reset pulse (815, 835, 855, 875) used in a greyscale update waveform (800, 820, 840 and 860). The monochrome update mode is used in combination with the greyscale update mode when possible.
摘要:
Electrophoretic display units (1,100) are provided with switching circuits (50) to reduce the energy necessary for supplying data pulses (DP1, DP2) to pixels (11) via a data electrode (31,32,33,34). This energy is proportional to a differential voltage to be realised and to a capacitance (13) to be charged or discharged, which is formed by a combination of a capacitance of the pixel (11) and a capacitance of the active matrix. Due to this capacitance of the active matrix being much larger, a relatively large amount of energy is necessary. The switching circuit (50) couples the data electrode (31,32,33,34) to a voltage reference source (REF) like ground between two selection pulses (SP1, SP2) to be supplied sequentially to two respective pixels (11) coupled to the same data electrode (31,32,33,34). This reduces the amount of discharging to be realized by the data drivers (3). As a result, the maximum energy necessary is reduced. To reduce the power consumption of the entire electrophoretic display unit (1,100), this should be done preferably for data pulses (DPI, DP2) having amplitudes with opposite polarity only.