JP2007519018A - Electrophoretic display unit - Google Patents

Abstract

The electrophoretic display unit (1) having a fixed frame time is relatively inflexible to drive. By introducing a line drive signal having a timing parameter, the frame rate can be made variable. According to the variable frame rate, the optical disturbance from the vibration pulse (Sh) is reduced, and the number of gray values is increased. The timing parameter represents the start delay of the line drive signal and / or represents the duration of the line drive signal. The line preferably has rows. All possible column drive signals and row delay parameters that define the row delay time for each column drive signal or for each frame are stored in a memory coupled to the controller (20). The oscillation pulse (Sh) is supplied with a minimum row delay time, the reset pulse (R) is supplied with a maximum row delay time, and the drive pulse (Dr) is supplied with a flexible row delay time. This corresponds to the product of the time interval and the step value defined by multiple bits.

Description

  The present invention relates to an electrophoretic display unit, a display device having an electrophoretic display unit, a method for driving the electrophoretic display unit, and a processor program product for driving the electrophoretic display unit.

  Examples of this type of display device are monitors, laptop computers, personal digital assistants (PDAs), mobile phones, electronic books, electronic newspapers, and electronic magazines.

  A prior art electrophoretic display unit is known from international patent application WO 99/53373. This patent application discloses an electronic ink display having two substrates, one of which is transparent and has a common electrode (also known as a counter electrode) and the other The substrate is provided with pixel electrodes arranged in rows and columns. The intersection between the row and column electrodes is associated with the pixel. The pixel is formed between a part of the common electrode and the pixel electrode. The pixel electrode is coupled to the drain of the transistor, the source of the transistor is coupled to the column electrode, and the gate of the transistor is coupled to the row electrode. The pixel, transistor, and row and column electrode configurations work together to form an active matrix. A row driver (selection driver) supplies a row drive signal, that is, a selection signal for selecting a pixel in a certain row, and a column driver (data driver) receives a column drive signal, that is, a data signal via column electrodes and transistors. To supply the selected row of pixels. The data signal corresponds to the data to be displayed and, in cooperation with the selection signal, forms (part of) a drive signal that drives one or more pixels.

  Furthermore, electronic ink is provided between the pixel electrode and the common electrode provided on the transparent substrate. The electronic ink has a plurality of microcapsules approximately 10 to 50 microns in diameter. Each microcapsule has positively charged white particles and negatively charged black particles suspended in a liquid. When a positive electric field is applied to the pixel electrode, the white particles move to the side of the microcapsule facing the transparent substrate, and the pixel becomes visible to the observer. At the same time, the black particles move to the pixel electrode on the opposite side of the microcapsule, where they are not visible to the observer. By applying a negative electric field to the pixel electrode, the black particles move to the common electrode on the side of the microcapsule facing the transparent substrate, and the pixel appears dark to the observer. At the same time, the white particles move to the pixel electrode on the opposite side of the microcapsule, where they are not visible to the observer. When the electric field is removed, the display device remains in the state obtained by the movement of the particles and exhibits bistability.

  In order to reduce the pixel history dependence of the optical response of the electrophoretic display unit, the preset data signal is supplied before the data dependent signal is supplied. The preset data signal has a pulse, which is of sufficient energy to release the electrophoretic particle from resting on one of the two electrodes, but this particle reaches the other electrode. It represents too little energy. Since the pixel history dependency has been reduced, the optical responses for the same data are substantially equal regardless of the pixel history. The basic mechanism can be explained by the fact that the electrophoretic particles become stationary after the display device is switched to a predetermined state, for example black. Next, when the switch to the white state occurs, the particle momentum is small because the particle starting speed is close to zero. This increases the history dependency, and a long switching time is required to overcome this large dependency. Application of the preset data signal increases the momentum of the electrophoretic particles, thus reducing this dependency (and shorter switching times are possible).

  In order to update the pixels of the electrophoretic display unit, for each row, a row driving operation for supplying a selection signal to the row in order to select (drive) the row, and a pulse (for example, a pulse or data of a preset data signal) A column driving operation for supplying a dependency signal pulse or the like to a pixel is required. The time interval required to drive all the pixels in all rows once (by driving each row in turn and driving all the columns once in each row) is called a frame period.

  During the first set of frames, pulses of the preset data signal are supplied to the pixels, each pulse having a duration of one frame period. For example, the first pulse has a positive amplitude, the second pulse has a negative amplitude, the third pulse has a positive amplitude, and so on. As long as the duration of these alternating pulses is relatively short, the gray value displayed by the pixel does not change with these pulses.

  During the second set of frames having one or more frame periods, one or more pulses of the data dependent signal are provided. The data dependent signal has a duration of zero frame period, 1 frame period, 2 frame period, for example 15 frame periods. Thereby, a data-dependent signal having a duration of zero frame period corresponds to, for example, a pixel displaying full black (if the pixel has already displayed full black) (displays a specific gray value). The gray value does not change when driven with a pulse having a duration of zero frame period, in other words when driven with a pulse of zero amplitude). A data dependent signal having a duration of 15 frame periods has 15 consecutive pulses and corresponds, for example, to a pixel displaying perfect white. A data dependent signal having a duration of 1 to 14 frame periods has 14 pulses that are continuous from one pulse, for example a limited number between full black and full white. This corresponds to a pixel that displays one gray value of the gray values.

  Since each frame has the same fixed duration, driving the electrophoretic display unit is rather inflexible. The pulses of the preset data signal are of fixed duration and cannot be shortened so that optical disturbances that can occur due to particle disturbances during the first set of frames are reduced. The number of gray values is limited and cannot be increased, and the difference between two consecutive gray values is quite large.

  Known electrophoretic display units are particularly disadvantageous because they are relatively inflexible in driving electrophoretic display units.

  An object of the present invention is, in particular, to provide an electrophoretic display unit having a relatively flexible driving method.

  The invention is defined by the independent claims. The dependent claims define advantageous embodiments.

  Another object of the present invention is to provide a display device having an electrophoretic display unit with a relatively flexible driving method, and an electrophoretic display with a relatively flexible driving method. A method for driving an electrophoretic display unit for use in a unit (or for use in combination with an electrophoretic display unit) and a processor program product for driving the electrophoretic display unit.

The electrophoretic display unit according to the present invention comprises:
An electrophoretic display panel having lines with pixels,
A line driver for driving the line, and a controller for supplying a line drive signal having a timing parameter to the line driver, the controller changing the timing parameter to change the frame rate of the electrophoretic display unit,
Have

  By using line drive signals having timing parameters, the frame rate of the electrophoretic display unit can be changed by changing these timing parameters. This provides a more flexible drive.

  In one embodiment, the timing parameter is formed by delaying the start of the line drive signal. By delaying the start of driving of at least one line, the duration of the frame in which driving of one or more lines is delayed is no longer fixed, but depends on the line delay used. A line corresponds to a column or row. In general, the frame delay time is the sum of all line delay times. Usually, but not exclusively, all rows in a frame have the same line delay time, where the frame delay time is the product of this line delay time and the number of lines. The line delay time can vary for one or more frames, resulting in a variable frame delay time and a variable frame rate. As a result, the drive becomes more flexible as shown below.

  The conventional frame rate is, for example, 50 Hz, and the conventional frame rate is increased to, for example, 130 Hz so that a line delay time can be introduced. At this frame rate, the minimum frame time is 7.7 ms. By introducing a frame delay between 0 ms and 45.9 ms, the maximum frame time is 53.6 ms. Supplying pulses of the preset data signal introduces a minimum frame delay (in other words, no delay is introduced). In this case, optical disturbance occurs at a frame rate of 130 Hz. Such a disturbance is less visible compared to an optical disturbance at a frame rate of 50 Hz. Supplying a pulse of data dependent signal introduces a frame delay of between 0 ms and 45.9 ms for one or more frames. As a result, the gray value to be displayed can be more accurately defined. Thus, for example, one frame has a first frame delay time, and the other frame has a second frame delay time different from the first frame delay time. At this time, for example, one pixel is driven during this one frame by supplying a pulse with an amplitude of 15 V during this one frame, and a pulse with an amplitude of 0 V during the other frame. Is driven during the other frames. As a result, the gray value display changes in proportion to one frame period. The other pixels are driven during this one frame by being supplied with a pulse with an amplitude of 0 V during this one frame, and a pulse with an amplitude of 15 V is supplied during the other frame. To drive during the other frame. As a result, the gray value changes in proportion to other frame periods. In this way, different pixels can display different gray levels.

  In another embodiment, the timing parameter is formed by the duration of the line drive signal of the line. This embodiment can be combined with the previously mentioned embodiments.

  When the timing parameter corresponds to a product of a predetermined time interval and a step value defined by a plurality of bits, the timing parameter can be easily realized.

  When a line is a row, when one or more row drivers drive a pixel in a row, all transistors coupled to the pixel in that row are turned on, after which one or more column drivers are connected to the column. The present invention is particularly advantageous because data can be supplied to the pixels of the row through the conducting transistors. Since one or more row drivers control all the transistors in the row, row delay time can be easily introduced. Row drivers are also known as selection drivers.

  An embodiment of the electrophoretic display unit according to the invention is defined in claim 6. In a memory coupled or incorporated in the controller, for example, all possible column drive signals (each column drive signal has a pulse of a preset data signal preceding one or more pulses of the data dependent signal), for example Column information to be supplied to the pixels of the plurality of column drive signals by storing information on timing parameters such as row delay parameters defining row delay times for each column drive signal and / or for each frame The amount of line delay required when selecting is automatically generated. Other pixels in the same row, possibly requiring another row delay time, are driven with a pulse of 0V amplitude during this frame, so that the previous gray value of these other pixels is displayed unchanged. Become so. Column drive signals are also known as data signals.

  The vibration pulse corresponds to, for example, the pulse of the preset data signal described above. The drive pulse corresponds, for example, to the data dependent signal pulse described above. The reset pulse precedes the drive pulse and further improves the optical response of the electrophoretic display unit by defining a fixed start point (fixed black or fixed white) of the drive pulse. Alternatively, the reset pulse precedes the drive pulse and is the flexible starting point of the drive pulse (black or white, selected depending on the gray value to be defined by the subsequent drive pulse and closest to this gray value) By further improving the optical response of the electrophoretic display unit. Since the oscillation pulse usually requires the frame to be as short as possible and the reset pulse usually requires the frame to be as long as possible, for example, the first row delay time is a fixed row delay time and the first One row delay time is shorter than the second row delay time. The third row delay time is a flexible row delay time because drive pulses usually require the frame to be flexible in order to increase the possible number of gray values to be displayed. The second row delay time can be fixed or flexible.

  The display device can be an electronic book, and the storage medium for storing information can be a memory stick, integrated circuit, memory, or other storage device for storing the contents of a book to be displayed, for example on a display unit Can do.

  Embodiments of the method according to the invention and the processor program product according to the invention correspond to the embodiments of the electrophoretic display unit according to the invention.

  The present invention is based in particular on the insight that the conventional fixed frame time makes the drive inflexible, in particular making the frame time variable by introducing a line drive signal with timing parameters. It is based on the basic concept of being able to.

  The present invention solves the problem of providing an electrophoretic display unit, in particular with a relatively flexible drive scheme, and in particular reduces and possibly possible optical disturbances from pulses of preset data signals This is advantageous in that it increases the number of significant gray values.

  These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

  The pixel 11 of the electrophoretic display unit shown in FIG. 1 (in cross section) is an electrophoretic film (on the base substrate 2) having electronic ink existing between the base substrate 2 and two substrates 3, 4 of eg polyethylene. Are stacked). One of the substrates 3 is provided with a transparent pixel electrode 5, and the other substrate 4 is provided with a transparent common electrode 6. The electronic ink has a plurality of microcapsules 7 having a diameter of about 10 to 50 microns. Each microcapsule 7 has positively charged white particles 8 and negatively charged black particles 9 suspended in a liquid 10. When a positive electric field is applied to the pixel electrode 5, the white particles 8 move to the side of the microcapsule 7 facing the common electrode 6, and the pixel becomes visible to the observer. At the same time, the black particles 9 move to the opposite side of the microcapsules 7, where the black particles 9 are hidden from the observer. By applying a negative electric field to the pixel electrode 5, the black particles 9 move to the side of the microcapsule 7 facing the common electrode 6, and the pixel appears dark to the observer (not shown). When the electric field is removed, the particles 8, 9 will remain in the state obtained by their movement, the display will be bistable and consume substantially no power.

  The electrophoretic display unit 1 shown in FIG. 2 has a display panel DP, which is an intersection of row electrodes or selection electrodes 41, 42, 43 and column electrodes, ie, data electrodes 31, 32, 33. The region has a matrix of pixels 11. All these pixels 11 are coupled to a common electrode 6, and each pixel 11 is coupled to its own pixel electrode 5. The electrophoretic display unit 1 further includes a row driver 40 coupled to the row electrodes 41, 42, 43 and a column driver 30 coupled to the column electrodes 31, 32, 33, and an active switching element for each pixel 11. Twelve. The electrophoretic display unit 1 is driven by these active switching elements 12 ((thin film) transistors in this embodiment). The row driver 40 continuously selects the row electrodes 41, 42, 43, while the column driver 30 supplies data signals to the column electrodes 31, 32, 33. Preferably, the controller 20 first processes the input data that arrives via the input unit 21 and then generates a data signal. Mutual synchronization between the column driver 30 and the row driver 40 is performed via drive lines 23 and 24. A selection signal from the row driver 40 selects the pixel electrode 5 via the transistor 12. The drain electrode of transistor 12 is electrically coupled to pixel electrode 5, the gate electrode of transistor 12 is electrically coupled to row electrodes 41, 42, 43, and the source electrode of transistor 12 is coupled to column electrodes 31, 32, 33. Electrically coupled. At the same time, the data signals present on the column electrodes 31, 32, 33 are sent to the pixel electrode 5 of the pixel 11 coupled to the drain electrode of the transistor 12. Other switching elements such as diodes and MIMs can be used instead of transistors. The data signal and the selection signal cooperate to form (part of) the drive signal.

  Input data such as image information that can be received via the input unit 21 is processed by the controller 20. Furthermore, the controller 20 detects the arrival of new image information related to the new image, and in response thereto, starts processing the received image information. This process of image information includes reading this new image information, comparing the previous image stored in the memory of the controller 20 with this new image, communicating with the temperature sensor, and a look-up table for the drive waveform. Including memory access, etc. Finally, the controller 20 detects when the processing of the image information is completed.

  The controller 20 then generates a data signal to be supplied to the column driver 30 via the drive line 23 and generates a selection signal to be supplied to the row driver 40 via the drive line 24. The data signal includes a data-independent signal that is the same for all the pixels 11 and a data-dependent signal that may or may not be different for each image 11. The data independent signal has a vibration pulse that forms a preset pulse, and the data dependent signal has one or more reset pulses and one or more drive pulses. The vibration pulse has a pulse representing energy, and this energy is sufficient to release the electrophoretic particles 8 and 9 from a stationary state at one of the two electrodes 5 and 6. However, the energy is too small for the particles 8 and 9 to reach the other of the electrodes 5 and 6. Since the history dependence is low, the optical responses for the same data are substantially equal regardless of the pixel history. Therefore, the vibration pulse reduces the dependence of the optical response of the electrophoretic display unit on the pixel history. The reset pulse further improves the optical response by defining a flexible starting point of the drive pulse prior to the drive pulse. This starting point can be a black level or a white level, which is selected depending on the gray value defined by the subsequent drive pulse and is closest to this gray value. Alternatively, the reset pulse can form part of a data independent signal, further improving the optical response of the electrophoretic display unit by defining a fixed starting point of the drive pulse prior to the drive pulse. Can do. This starting point can be a fixed black level or a fixed white level.

  FIG. 3 shows a waveform representing the voltage applied to the pixel 11 for driving the electrophoretic display unit 1 as a function of time t. This waveform is generated using a data signal supplied via the column driver 30. This waveform has a vibration pulse Sh followed by a combination of a reset pulse R and a combination of a drive pulse Dr. For example, for an electrophoretic display unit having four gray levels, 16 different waveforms may form part of the controller 20 and / or be coupled to the controller 20, such as a look-up table memory, for example. Is remembered. In response to data received via input 21, controller 20 selects a waveform for one or more pixels 11, via corresponding drivers 30, 40, corresponding transistors 12 and corresponding ones. Corresponding selection signals and data signals are supplied to the pixels 11 described above.

  The frame period corresponds to the time interval used to drive all the pixels 11 of the electrophoretic display unit 1 once by driving each row in turn and driving all the columns once for each row. During the data-independent frame period (data-independent part of the frame period), a data-independent signal is supplied to the pixel 11, and during the data-dependent frame period (data-dependent part of the frame period), the data-dependent signal is supplied to the pixel 11. Supplied. Thus, in FIG. 3, each pulse is shown as a special voltage level between two successive transitions and represents a separate frame period.

  During the first set of frames, a vibration pulse Sh is supplied to the pixel 11 and each vibration pulse has a duration of one frame period. For example, the first vibration pulse has a positive amplitude, the second vibration pulse has a negative amplitude, the third vibration pulse has a positive amplitude, and so on. These oscillating pulses with alternating amplitude do not change the gray value displayed by the pixel 11 as long as the frame period is relatively short.

  During the second set of frames having one or more frame periods, the combination of reset pulses R is supplied as further described below. During a third set of frames having one or more frame periods, a combination of drive pulses Dr is provided, the combination of drive pulses Dr being a pulse having a duration of zero frame periods and actually having an amplitude of zero. Or have a duration of 1 frame period, 2 frame periods, for example 15 frame periods. Thereby, the drive pulse Dr having a duration of zero frame period corresponds to, for example, a pixel displaying perfect black (if the pixel 11 has already displayed perfect black) (displaying a specific gray value). The gray value does not change when driven with a pulse having a duration of zero frame period, in other words, when driven with a pulse with zero amplitude). A combination of drive pulses Dr having a duration of 15 frame periods has 15 consecutive pulses and corresponds to, for example, a pixel 11 that displays complete white. A combination of drive pulses Dr having a duration of one frame period to 14 frame periods has 14 pulses continuous from one pulse, for example, limited between full black and full white This corresponds to the pixel 11 displaying one gray value of the number of gray values.

  The reset pulse R further improves the optical response of the electrophoretic display unit 1 by defining a fixed start point (fixed black or fixed white) of the drive pulse Dr prior to the drive pulse Dr. Alternatively, the reset pulse R is a flexible starting point of the driving pulse Dr (black or white) preceding the driving pulse Dr, which depends on the gray value to be defined by the following driving pulse. The optical response of the electrophoretic display unit is further improved.

  Since the conventional electrophoretic display unit 1 has all the same fixed duration, the driving of the conventional electrophoretic display unit 1 is not very flexible. The oscillating pulse Sh is of fixed duration and cannot be shortened so that optical disturbances that can occur due to particle disturbances during the first set of frames are reduced. The number of gray values is limited and cannot be increased, and the difference between two consecutive gray values is quite large.

  According to the present invention, by introducing a line drive signal having a timing parameter, the controller 20 can change the frame rate of the electrophoretic display unit 1 by changing one or more timing parameters. The timing parameter is formed, for example, by delaying the start of a line drive signal such as a row drive signal. By delaying the supply of the row drive signal, the duration of the frame period that is not fixed and that depends on the delay amount of the row delay time used to delay the row drive signal of the corresponding row The duration is obtained. The resulting increase in frame period is the sum of all row delay times. Usually, although not exclusively, each of a plurality of rows in a frame has the same row delay time, and the increase in the frame period is the product of this row delay time and the number of rows. The row delay time can be changed for each frame, resulting in a variable frame period and a variable frame rate. Such a variable frame rate enables more flexible driving as described below.

  The conventional frame rate is 50 Hz, for example, and this increases to 130 Hz. At this frame rate, the minimum frame period is 7.7 msec. By introducing a frame period increase between 0 msec and 45.9 msec, the maximum frame period is 53.6 msec. When the vibration pulse Sh is supplied, a minimum frame period (in other words, no delay is introduced) is introduced. The optical disturbance at a frame rate of 130 Hz is less visible than the optical disturbance at a frame rate of 50 Hz. The gray value to be displayed via the pixel 11 is realized by supplying one or more drive pulses Dr to the pixel 11 during one or more frame periods. When the drive pulse Dr is supplied during one or more frame periods of the plurality of frame periods, an increase in the frame period between 0 msec and 45.9 msec is introduced. As a result, one or more drive pulses Dr can be more accurately defined, and the gray value to be displayed is more accurately defined. Thus, for example, one frame has a first frame period and the other frame has a second frame period different from the first frame period. For example, one pixel 11 is driven during the one frame period by supplying a pulse with an amplitude of 15 V to the one pixel 11 during one frame period. The one pixel 11 is driven during the other frame period by supplying a pulse having an amplitude of 0V to the one pixel 11 during the other frame period, and thus, the previous gray value. The display will not change. The other pixel 11 is driven during the one frame period by supplying a pulse having an amplitude of 0V to the other pixel 11 during the one frame period. The display does not change. The other pixel 11 is driven during the other frame period by supplying a pulse having an amplitude of 15 V to the other pixel 11 during the other frame period. Accordingly, more gray levels with higher accuracy can be displayed by the pixels 11.

  FIG. 4 shows an old frame Fo with a fixed row drive signal (upper graph) and a new frame Fn with a flexible row drive signal (middle graph and lower graffle). In the upper graph, for ease of understanding, only two old (no delay) row drive signals r1, r2 are shown for each old frame Fo. In the middle graph, only two new (delayed) row drive signals r3, r4 are shown for each new frame Fn for ease of understanding. The row drive signal r3 has a row delay amount d1, and the row drive signal r4 has a row delay amount d2. In other words, the delay amount d1 corresponds to the start delay amount of the row drive signal r3. The delay amount d2 corresponds to the start delay amount of the row drive signal r4. In the lower graph, for ease of understanding, only two new row drive signals r5, r6 are shown for each new frame Fn. The row drive signals r5, r6 have a longer duration than the row drive signals r3, r4, and according to this embodiment, the duration of one of the row drive signals r5; The time is equal to the sum of the duration of one of the row drive signals r3; r4 and its row delay amount d1; d2. This results in a new frame Fn with a longer duration than the old frame Fo, which duration drives the total row delay time used to drive all rows and / or drives all rows. Depends on the duration of all row drive signals. By changing the row delay time for each row and / or the duration of the row drive signal, the frame rate is flexible. Of course, the generation of a flexible frame rate by the flexible duration of the row drive signal can be realized in a simple manner by changing the clock frequency. Alternatively, the end of the row drive signal can be delayed to achieve a flexible duration.

  The first row delay parameter defines a first row delay time for the vibration pulse Sh, the second row delay parameter defines a second row delay time for the reset pulse R, and a third row. The delay parameter defines a third row delay time for the drive pulse Dr. Usually, the first and second delay times are fixed row delay times. Since the oscillation pulse Sh requires that the frame be as short as possible and the reset pulse R requires that the frame be as long as possible, for example, the first row delay time is shorter than the second row delay time. Since the drive pulse Dr requires that the frame be flexible in order to increase the number of displayable gray values, the third row delay time is a flexible row delay time. Alternatively, the second row delay time can be a flexible row delay time.

  A memory (not shown) coupled or incorporated into the controller 20 is used to store information to be displayed and / or to store all possible column drive signals. Each column drive signal has, for example, one or more reset pulses R and a vibration pulse Sh preceding one or more drive pulses Dr. The memory is also used to store information about timing parameters such as row delay time and / or duration. The necessary timing parameters are automatically generated when selecting one of the plurality of column drive signals to be supplied to the pixel 11. Other pixels 11 in the same row, possibly requiring another frame period (to generate another gray value), are driven with a pulse of 0V amplitude during this frame, thereby causing the other The pixel 11 of the second display is the same as the previous gray value.

  For example, the row delay time corresponds to a product of a predetermined time interval of, for example, 0.30 μsec and a step value n defined by a plurality of bits, for example, 8 bits (256 steps). At that time, the row delay time can be defined in the form of a step value n (0 ≦ n ≦ 255) by the row delay parameter. After reading the column drive signal and the corresponding 8-bit row delay parameter from the memory, the controller 20 multiplies the step value n by a predetermined time interval to generate a row delay time. The duration of the row drive signal also corresponds to this product.

  In the experiment, for example, at a frame rate of 130 Hz, a row time of 12.78 μsec was obtained. Since the processing time (for executing the above processing) is 54.3 μsec, for example, in 600 rows, the minimum frame period is 54.3 + 12.78 * 600 = 7722 μsec≈7.7 msec. By introducing a row delay time of n * 0.30 μsec, the frame period becomes 7.7 + 0.18 * n msec. At that time, the maximum frame period is 7.7 + 0.18 * 255 msec = 53.6 msec.

  It should be noted that the above embodiments are not intended to limit the invention and that many other embodiments can be designed by those skilled in the art without departing from the scope of the appended claims. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The singular form of a component does not exclude the presence of a plurality of such elements. The present invention can be implemented by hardware having several separate elements and by a suitably programmed computer. In the device claim enumerating several means, several of these means can be realized by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Pixels are shown (in cross section). 1 schematically shows an electrophoretic display unit. The waveform for driving an electrophoretic display unit is shown. 2 shows an old frame with a fixed row drive signal and a new frame with a flexible row drive signal.

Claims (11)

An electrophoretic display panel having lines with pixels,
A line driver for driving the line; and a controller for supplying a line drive signal having a timing parameter to the line driver, the controller changing the timing parameter to change a frame rate of the electrophoretic display unit;
An electrophoretic display unit.   The electrophoretic display unit according to claim 1, wherein the timing parameter is formed by delaying a start of the line driving signal.   The electrophoretic display unit according to claim 1, wherein the timing parameter is formed by a duration of a line driving signal of a line.   The electrophoretic display unit according to claim 1, wherein the timing parameter corresponds to a product of a predetermined time interval and a step value defined by a plurality of bits.   The electrophoretic display unit according to claim 1, wherein the line corresponds to a row.   The electrophoretic display unit according to claim 1, further comprising a memory coupled to or incorporated in the controller, the memory storing information related to the timing parameter. The information includes a row delay parameter, the driving signal includes a column driving signal and a row driving signal, and the column driving signal and the row driving signal are:
An oscillating pulse having a first row delay parameter defining a first row delay time;
One or more reset pulses having a second row delay parameter defining a second row delay time;
One or more drive pulses having a third row delay parameter defining a third row delay time;
Provide
The first row delay time is a fixed row delay time, the first row delay time is shorter than the second row delay time, and the third row delay time is a flexible row delay time. The electrophoretic display unit according to claim 6.   A display device comprising: the electrophoretic display unit according to claim 1; and a storage medium for storing information to be displayed. A method of driving an electrophoretic display unit having an electrophoretic display panel having lines with pixels, the method comprising:
-Changing a timing parameter of a line drive signal to change a frame rate of the electrophoretic display unit; and-driving the line with the line drive signal;
Having a method. A computer program for driving an electrophoretic display unit, the computer program comprising:
A function of driving a line with pixels of the electrophoretic display unit in response to a line drive signal; and a line drive signal having a timing parameter that can be varied to change a frame rate of the electrophoretic display unit. Function to supply,
A computer program.   A controller for supplying a line drive signal having a timing parameter to a line driver for driving a line with pixels of the electrophoretic display unit, the timing parameter for changing a frame rate of the electrophoretic display unit. Change the controller.

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