CN111276104B - Driving method, driving device and waveform generator of electrophoretic display - Google Patents

Abstract

The present application discloses a driving method, a driving device and a waveform generator for an electrophoretic display, which relate to but are not limited to the technical field of electrophoretic display. A driving method for an electrophoretic display includes: refreshing the grayscale of an original image to an initial grayscale ; Obtain a voltage signal with a preset time length, and refresh the initial gray scale to the reference gray scale; the time length is set according to the brightness change of the electrophoretic display; write the gray scale of the new image. The driving method, driving device and waveform generator of the electrophoretic display disclosed in the present application can reduce the time length of the driving waveform without affecting the display quality, thereby improving the response speed of the EPD.

Description

Driving method, driving device and waveform generator of electrophoretic display

technical field

The embodiments of the present application relate to, but are not limited to, the technical field of electrophoretic displays, and in particular, relate to a driving method, a driving device, and a waveform generator for an electrophoretic display.

Background technique

Electrophoretic display (EPD) is a non-self-luminous device based on the electrophoresis phenomenon of charged pigment particles suspended in a solvent. It not only has the advantages of wide viewing angle, rewritable, paper-like display, etc. Light readable characteristics. The grayscale display of an electrophoretic display depends on the distribution of black and white particles, and the distribution of black and white particles depends on the applied voltage timing, that is, the driving waveform. The optimization of the driving waveform directly affects the display effect of the display.

In the driving waveform optimization process, the time length of the driving waveform is one of the key factors limiting the response speed of the EPD. Currently, the drive waveform is divided into three phases: erasing the previous frame, activating charged particles, and displaying a new frame. In order to reduce the time length of the driving waveform, one method is to remove the stage of activating the charged particles by inserting the response delay time. Although this method can erase the previous frame image well, after writing the image for many times, due to The uniformity of the particle state is getting worse and worse, creating ghost images. Another approach is to study the short waveform of the EPD and divide the short waveform into three stages: zero voltage bias, high frequency activation, and positive and negative voltage drive. Although this method can reduce the time length of the driving waveform, it reduces the display quality of the EPD.

SUMMARY OF THE INVENTION

The embodiments of the present application aim to solve one of the technical problems existing in the prior art at least to a certain extent. To this end, an embodiment of the present application proposes a driving method for an electrophoretic display, which can reduce the time length of the driving waveform without affecting the display quality, thereby improving the response speed of the EPD.

The embodiments of the present application also provide a driving device for an electrophoretic display.

The embodiment of the present application also provides a waveform generator.

In a first aspect, an embodiment of the present application provides a method for driving an electrophoretic display, the method comprising:

Refresh the grayscale of the original image to the initial grayscale;

Obtain a voltage signal of a preset time length, and refresh the initial grayscale to the reference grayscale; the time length is set according to the brightness change of the electrophoretic display;

Write the grayscale of the new image.

The driving method of the electrophoretic display according to the embodiment of the present application has at least the following beneficial effects:

1. Refresh the initial grayscale to the reference grayscale, so that the distribution of charged particles in the microcapsules is unified, which is conducive to the more regular and accurate display of the next grayscale, and can reduce ghosting;

2. Obtaining a voltage signal with a preset time length can reduce the time length of the driving waveform without affecting the display quality, thereby improving the response speed of the EPD.

According to the driving method of the electrophoretic display according to other embodiments of the present application, the initial grayscale includes any one of the following four types: black grayscale, dark grayscale, light grayscale and white grayscale;

The reference grayscale is the white grayscale.

In the driving method of the electrophoretic display according to the embodiment of the present application, the black grayscale, the dark grayscale, the light grayscale and the white grayscale are respectively used as the initial grayscale, and in the process of refreshing the initial grayscale to the reference grayscale, determine The time length of the drive waveform.

According to the driving method of an electrophoretic display according to other embodiments of the present application, the voltage signal includes: a positive voltage signal of a first time length and a negative voltage signal of a second time length.

In the driving method of the electrophoretic display according to the embodiment of the present application, the process of refreshing the initial gray level to the reference gray level is divided into two time stages, the first stage obtains a positive voltage signal of a first time length, and the second stage obtains a second time length negative voltage signal. The distribution of charged particles in the microcapsules is unified, which is conducive to a more regular and accurate display of the next grayscale, and can reduce ghosting.

According to the driving method of the electrophoretic display according to other embodiments of the present application, setting the first time length according to the brightness change of the electrophoretic display includes:

Obtain a positive voltage signal, start to refresh the initial grayscale, and record the brightness value of the electrophoretic display that changes with time;

Calculate the change rate of the brightness value, and record the time length corresponding to the maximum value of the change rate;

The duration is set to the first duration.

In the driving method of the electrophoretic display of the embodiment of the present application, the first time length is set according to the brightness change of the electrophoretic display. The brightness change of the electrophoretic display can reflect the motion characteristics of the particles, and the faster the brightness change, the faster the movement speed of the particles is reflected. The faster the moving speed of the particles, the higher the activity of the particles, which is more conducive to the driving of the next stage. The time length corresponding to the change rate of the luminance value of the electrophoretic display reaching the maximum value is set as the first time length, that is, after the voltage driving of the first time length, the activity of the particles reaches the highest state.

According to the driving method of the electrophoretic display according to other embodiments of the present application, setting the second time length according to the brightness change of the electrophoretic display includes:

Obtain the negative voltage signal and record the brightness value of the electrophoretic display that changes with time;

The length of time corresponding to the record refresh to the reference grayscale;

Set the duration to the second duration.

In the driving method of the electrophoretic display according to the embodiment of the present application, the second time length is set according to the brightness change of the electrophoretic display, and after the voltage driving of the first time length, the activity of the particles reaches the highest state, that is, close to the optical limit state, and starts at this time. It is easier to refresh to a stable reference gray scale by performing the voltage driving for the second time length.

According to the driving method of the electrophoretic display according to other embodiments of the present application, the first time length is 60ms, and the second time length is 140ms.

Compared with the traditional driving waveform, the driving method of the electrophoretic display according to the embodiment of the present application reduces the driving time by 280ms, reduces the image texture by 0.541%, and improves the image uniformity by 0.373%. The white grayscale of 2.7 grayscales has been improved.

In a second aspect, an embodiment of the present application provides a driving device for an electrophoretic display, the device includes a data acquisition module and a waveform driving module; the data acquisition module is connected to the waveform driving module;

The data acquisition module is used to record the brightness value of the electrophoretic display that changes with time;

The waveform driving module is used to obtain a driving waveform, and the driving waveform includes a first voltage signal, a second voltage signal and a third voltage signal; the first voltage signal is used to refresh the grayscale of the original image to the initial grayscale, and the second voltage signal is used for For refreshing the initial grayscale to the reference grayscale, the third voltage signal is used to write the grayscale of the new image;

The waveform driving module is further configured to set the time length of the second voltage signal according to the brightness value.

The driving device of the electrophoretic display according to the embodiment of the present application has at least the following beneficial effects:

1. Use the waveform driving module to apply the driving voltage to refresh the initial grayscale to the reference grayscale, so that the distribution of charged particles in the microcapsules can be unified, which is conducive to the more regular and accurate display of the next grayscale, and can reduce ghosts. film;

2. Setting the time length of the driving voltage according to the brightness value collected by the data acquisition module can reduce the time length of the driving waveform without affecting the display quality, thereby improving the response speed of the EPD.

According to the driving device of an electrophoretic display according to other embodiments of the present application, the second voltage signal includes: a positive voltage signal of a first time length and a negative voltage signal of a second time length;

The first time length is the time length corresponding to the change rate of the luminance value reaching the maximum value;

The second time length is the time length corresponding to the refresh to the reference gray level.

In the driving device of the electrophoretic display according to the embodiment of the present application, the time length corresponding to the change rate of the luminance value of the electrophoretic display reaching the maximum value is set as the first time length, that is, after the voltage driving of the first time length, the activity of the particles reaches the maximum value. In the highest state, that is, close to the optical limit state, the voltage driving for the second time length is started at this time, and it is easier to refresh to a stable reference gray level.

In a third aspect, an embodiment of the present application provides a waveform generator, the waveform generator is used to generate a driving waveform, and the driving waveform includes a first voltage signal, a second voltage signal and a third voltage signal; the first voltage signal is used for refresh the grayscale of the original image to the initial grayscale, the second voltage signal is used to refresh the initial grayscale to the reference grayscale, and the third voltage signal is used to write the grayscale of the new image;

The waveform generator is also used for setting the time length of the second voltage signal according to the brightness change of the electrophoretic display.

The waveform generator of the embodiment of the present application has at least the following beneficial effects:

1. Apply a driving voltage to refresh the initial grayscale to the reference grayscale, so that the distribution of charged particles in the microcapsules is unified, which is conducive to more regular and accurate display of the next grayscale, and can reduce ghosting;

2. Applying a voltage with a set time length according to the brightness change of the electrophoretic display can reduce the time length of the driving waveform without affecting the display quality, thereby improving the response speed of the EPD.

According to the waveform generator of other embodiments of the present application, the second voltage signal includes: a positive voltage signal of a first time length and a negative voltage signal of a second time length;

The first time length is the time length corresponding to the change rate of the luminance value of the electrophoretic display reaching the maximum value;

The second time length is the time length corresponding to the refresh to the reference gray level.

In the waveform generator of the embodiment of the present application, the time length corresponding to the change rate of the luminance value of the electrophoretic display reaching the maximum value is set as the first time length, that is, after the voltage driving of the first time length, the activity of the particles reaches the highest state , that is, close to the optical limit state, at this time, the voltage driving for the second time length is started, and it is easier to refresh to a stable reference gray scale.

Other features and advantages of the present application will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present application. The objectives and other advantages of the application may be realized and attained by the structure particularly pointed out in the description, claims and drawings.

Description of drawings

FIG. 1 is a schematic flowchart of a specific embodiment of a driving method for an electrophoretic display according to an embodiment of the present application;

2 is a schematic diagram of driving waveforms of a specific embodiment of a driving method for an electrophoretic display in an embodiment of the present application under different initial grayscales;

FIG. 3 is a schematic diagram of the luminance value curve of the stage of refreshing the initial gray scale to the black gray scale with time;

FIG. 4 is a schematic diagram of the luminance value curve of the stage of refreshing the black gray scale to the white gray scale with time;

5 is a schematic diagram of a driving waveform of a specific embodiment of a driving method for an electrophoretic display in an embodiment of the present application when the initial grayscale is a white grayscale;

6 is a schematic diagram of driving waveforms of another specific embodiment of a driving method for an electrophoretic display in an embodiment of the present application when the initial grayscale is a white grayscale;

7 is a schematic diagram of a conventional driving waveform;

FIG. 8 is a block diagram of a module of a specific embodiment of a driving device for an electrophoretic display according to an embodiment of the present application.

Detailed ways

The concept of the present application and the resulting technical effects will be clearly and completely described below with reference to the embodiments, so as to fully understand the purpose, features and effects of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative work belong to The scope of protection of this application.

In the description of this application, if the orientation description is involved, for example, the orientation or positional relationship indicated by "upper", "lower", "front", "rear", "left", "right", etc. is based on the drawings. The orientation or positional relationship is only for the convenience of describing the application and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the application . If a feature is referred to as "set", "fixed", "connected", "mounted" on another feature, it can be directly set, fixed, connected to the other feature, or indirectly set, fixed, connected , mounted on another feature.

In the description of the embodiments of the present application, if “several” is involved, it means more than one; if “multiple” is involved, it means more than two; ", should be understood as not including this number, if it involves "above", "below", "within", it should be understood as including this number. If it refers to "first" and "second", it should be understood to be used to distinguish technical features, but not to indicate or imply relative importance, or to imply indicate the number of indicated technical features or to imply indicate the indicated The sequence of technical features.

In the description of the embodiments of the present application, the terms "front", "rear" and "subsequent" with respect to driving waveform stages do not necessarily mean or require a time delay between stages. Subsequent stages can start immediately after the previous stage.

In the embodiments of the present application, the driving method can drive a typical array-type electrophoretic display unit in a pixel display. Electrophoretic display cells are provided with a common electrode (usually transparent). The substrate of the electrophoretic display unit includes dispersed pixel electrodes. Each pixel electrode defines a single pixel of a pixel electrophoretic display. In practice, however, a plurality of display units may be associated with a discrete pixel electrode, or a plurality of pixels may be associated with a single display unit. The pixel electrodes may be segmented in form, rather than pixellated, thereby defining areas of the image to be displayed rather than individual pixels. Therefore, although the term "pixel" is used in the embodiments of the present application to describe the driving implementation processes, these driving implementation processes are also applicable to segmented displays. The movement of charged particles within a display cell is determined by the potential difference applied to the common and pixel electrodes associated with the display cell.

In the embodiments of the present application, the term "driving voltage" is used to represent the potential difference experienced by charged particles in a pixel area. For example, if zero voltage is applied to the common electrode and +15V is applied to the pixel electrode, the "driving voltage" of the charged pigment particles in the pixel area is +15V.

The driving methods of the embodiments of the present application can be used for various forms of displays, including segmented displays and displays based on non-segmented pixels. There are various other approaches to implementing methods and apparatus for improved driving schemes for electrophoretic displays and other types of displays including, but not limited to, liquid crystal, roller ball, dielectrophoretic, and electrowetting.

Example 1

Referring to FIG. 1 , a schematic flowchart of a specific embodiment of a method for driving an electrophoretic display according to an embodiment of the present application is shown. As shown in FIG. 1 , the driving method of the electrophoretic display according to the embodiment of the present application includes the following specific steps:

S101. Refresh the grayscale of the original image to the initial grayscale.

In the original image, the spatial distribution of particles in each pixel is different, which makes each pixel have different grayscales when the voltage is applied for the same driving time, and drives the display to a uniform optical limit (black grayscale or white Grayscale), which is beneficial to eliminate the residual image. Before the driving waveform of the next stage, the particles of each pixel are in the same spatial position. This stage is called erasing the original image stage.

S102. Acquire a voltage signal of a preset time length, and refresh the initial gray scale to a reference gray scale; the time length is set according to the brightness change of the electrophoretic display.

If a pixel remains in the same state for a long time, the mobility of charged particles will increase, which is not conducive to the display of the next stage. By driving the display multiple times to reach the optical limit, it is beneficial to improve the activity of the particles and further eliminate ghost images. This stage is called the activated particle stage.

The embodiment of the present application divides the stage of activating particles into two stages: refreshing to black grayscale and refreshing to white grayscale. The main function of the stage of refreshing to black grayscale is to improve particle activity, thereby increasing the particle driving rate, and refreshing to white grayscale. The main function of the stage is to unify the reference gray level, to ensure that in the case of different initial gray levels and multiple refreshes, the particles can drive the particles to the same spatial position before writing a new image stage, usually choose to drive the display to the optical limit state.

S103. Write the grayscale of the new image.

The process of writing the gray scale of the new image is called the writing new image stage, including the writing stage for writing the new image and the voltage waveform of 0V, the waiting stage for waiting for all electrophoretic particles to complete the gray scale conversion, wherein, The duration of the phase of writing a new image (ie, the duration of the voltage waveform other than 0V) is equal to the duration of the phase of erasing the original image in step S101 .

In other embodiments of the present application, the initial grayscale includes any one of the following four types: black grayscale, dark grayscale, light grayscale, and white grayscale; the reference grayscale is white grayscale.

The black grayscale, the dark grayscale, the light grayscale and the white grayscale are respectively used as the initial grayscale, and the time length of the driving waveform is determined in the process of refreshing the initial grayscale to the reference grayscale.

In other embodiments of the present application, the voltage signal includes: a positive voltage signal of a first time length and a negative voltage signal of a second time length.

The process of refreshing the initial grayscale to the reference grayscale is divided into two time stages. The first stage obtains a positive voltage signal of a first time length, refreshes the initial grayscale to a black grayscale, and the second stage obtains a second time length. A negative voltage signal refreshes the black grayscale to the reference grayscale (white grayscale). In other embodiments of the present application, the positive voltage is +15V, and the negative voltage is -15V.

In other embodiments of the present application, setting the first time length according to the brightness change of the electrophoretic display includes: acquiring a positive voltage signal, starting to refresh the initial gray scale, and recording the brightness value of the electrophoretic display that changes with time; calculating the brightness value The change rate of , record the time length corresponding to the change rate reaching the maximum value; set the time length as the first time length.

The first time length is set according to the brightness change of the electrophoretic display. The brightness change of the electrophoretic display can reflect the motion characteristics of the particles. The faster the brightness changes, the faster the movement speed of the particles is. The faster the moving speed of the particles, the higher the activity of the particles, which is more conducive to the driving of the next stage. The time length corresponding to the change rate of the luminance value of the electrophoretic display reaching the maximum value is set as the first time length, that is, after the voltage driving of the first time length, the activity of the particles reaches the highest state.

In other embodiments of the present application, setting the second time length according to the brightness change of the electrophoretic display includes: acquiring a negative voltage signal, recording the brightness value of the electrophoretic display changing with time; Length of time; set the length of time to the second length of time.

The second time length is set according to the brightness change of the electrophoretic display. After the voltage driving of the first time length, the activity of the particles reaches the highest state, that is, close to the optical limit state (black gray scale). Voltage driven, it is easier to refresh to a stable reference grayscale (white grayscale).

In other embodiments of the present application, the first time length is 60ms, and the second time length is 140ms.

According to experimental calculations, compared with the traditional driving waveform, the driving waveform of the embodiment of the present application reduces the driving time by 280ms, reduces the image texture by 0.541%, and improves the image uniformity by 0.373%, which makes the white gray scale of the EPD. Improved by 2.7 gray levels. Example 2 will describe the experimental procedure in detail.

Example 2

The experiment adopts microcapsule EPD, and the experimental device is mainly divided into two parts: waveform editing system and data acquisition system. Among them, the work of the waveform editing system is mainly completed by the computer software LabVIEW, and the data acquisition system is composed of a driving power supply, a closed experimental box, a light source, a camera and a temperature controller.

The data acquisition system mainly collects the brightness value of the EPD display. Since the acquisition process is easily disturbed by external light, a closed experimental cabinet is required to prevent the interference of external light. The two light sources mainly provide the external light sources required by the data acquisition system. In a confined space, the light environment provided by the internal light source is relatively stable, which provides a good comparability for the driving effects of different electronic paper driving waveforms. The particle electrophoresis motion of the electronic paper microcapsule system is easily affected by temperature, and the experiment should be ensured to work in an environment of room temperature of 25 °C.

The waveform editing system is the software development platform LabVIEW. The waveform editing platform is written by the graphical programming G language, and the designed driving waveform is converted into a binary file, which is directly downloaded to the circuit for system call.

The driving waveform is divided into three stages: the first stage is to erase the original image, that is, to refresh the grayscale of the original image to white grayscale; the second stage is to activate the particles, which is divided into two types: refreshing to black grayscale and refreshing to white grayscale. The third stage writes a new image, that is, writes the grayscale of the new image.

Referring to FIG. 2 , a schematic diagram of driving waveforms of a specific embodiment of a driving method of an electrophoretic display according to an embodiment of the present application is shown under different initial gray scales. Using the driving waveforms of the embodiments of the present application, the black grayscale (B), the dark grayscale (DG), the light grayscale (LG), and the white grayscale (W) are respectively used as the initial grayscales. Refreshes the luminance value of the stage to black grayscale, and plots the luminance value as a function of time.

Referring to FIG. 3 , a schematic diagram of a luminance value curve over time in the stage of refreshing the initial grayscale to the black grayscale is shown. It can be seen from the brightness value curve shown in Fig. 3 that the brightness value gradually decreases with the change of time, and the decreasing speed is first fast and then slow, which means that the moving speed of the particles first increases and then decreases. In order to calculate the change of particle motion speed, the first-order derivation of the brightness value curve is performed to obtain the brightness value change rate curve.

It can be seen from the curve of the change rate of the brightness value that when the time length is 40-60ms, the change rate of the brightness value is the highest, indicating that the movement rate of the particles is the highest. It can be seen from this that the particle activity is the highest when the driving time in the stage of refreshing the initial grayscale to the black grayscale is 40-60 ms. In a state with high particle activity, it is beneficial to drive in the next stage.

The driving time of the stage of refreshing the initial grayscale to the black grayscale is set to 40ms, 45ms, 50ms, 55ms, and 60ms, respectively, the luminance value of the stage of refreshing the black grayscale to the white grayscale is measured, and the luminance value is plotted with time. changing curve.

Referring to FIG. 4 , a schematic diagram of a luminance value curve over time in a stage of refreshing a black grayscale to a white grayscale is shown. As shown in FIG. 4 , the driving time of the stage of refreshing the initial grayscale to the black grayscale is set to 40ms, 50ms, 60ms and the conventional driving time (240ms), respectively, and the driving time of the stage of refreshing the black grayscale to the white grayscale is measured. The luminance value was used to study the influence of the driving time of the stage of refreshing the initial grayscale to the black grayscale on the driving time of the stage of refreshing the black grayscale to the white grayscale.

Referring to FIG. 5 , a schematic diagram of driving waveforms of a specific embodiment of a driving method of an electrophoretic display in an embodiment of the present application is shown when the initial gray scale is a white gray scale. In the driving waveform of the embodiment of the present application, the driving time in the stage of refreshing the initial gray scale to the black gray scale is set to 40 ms.

Referring to FIG. 6 , a schematic diagram of driving waveforms of another specific embodiment of a driving method for an electrophoretic display in an embodiment of the present application is shown when the initial gray scale is a white gray scale. In the driving waveform of the embodiment of the present application, the driving time in the stage of refreshing the initial gray scale to the black gray scale is set to 60 ms.

Referring to FIG. 7, a schematic diagram of a conventional driving waveform is shown. The driving time of the activation particle stage of the conventional driving waveform is 480ms, the driving time of the stage of refreshing the initial grayscale to black grayscale and the driving time of the stage of refreshing the black grayscale to white grayscale are both 240ms.

Using the driving waveform shown in Figure 5, when the driving time of the stage of refreshing the black grayscale to the white grayscale is 0, the brightness value of the display is 33ints, and the screen does not reach the optical limit state (black grayscale), which is not conducive to The drive for the next stage. Therefore, the driving time of 40 ms is not suitable as the driving time length of the stage of refreshing the initial gray scale to the black gray scale.

Using the driving waveform shown in FIG. 6 , when the driving time in the stage of refreshing the black grayscale to the white grayscale is 0, the luminance value of the display is lower than 30ints, which is close to the optical limit state (black grayscale). The time to refresh the black grayscale to a stable reference grayscale (white grayscale) is 140ms. This shows that the driving time of the stage of refreshing the initial grayscale to the black grayscale is set to 60ms, which is easier to drive to a stable reference grayscale than the traditional driving waveform.

Using the driving waveform shown in Figure 6, the black grayscale (B), the dark grayscale (DG), the light grayscale (LG) and the white grayscale (W) are used as the initial grayscales, respectively, and the black grayscale is measured. The brightness value of the stage at which the level is refreshed to the white gray level, and the curve of the change of the brightness value with time is plotted.

It can be seen from the luminance value curve that in the four-level grayscale, using the driving waveform shown in Figure 6, the time for refreshing the black grayscale to the stable white grayscale is 140ms, which is 100ms less than the traditional driving waveform.

Compared with the traditional driving waveform, using the driving waveform shown in Figure 6, the time length of the activation particle stage is reduced by 280ms, wherein the driving time of the stage of refreshing the initial grayscale to the black grayscale is reduced by 180ms, and the black grayscale is reduced by 180ms. The driving time of the stage of level refresh to the reference gray level is reduced by 100ms.

The gray value of the display was measured by refreshing the EPD to a white gray scale using the driving waveform shown in Figure 6 and the conventional driving waveform shown in Figure 7, respectively. The results show that using the driving waveform shown in Figure 6 can improve the white gray level of the EPD by 2.7 gray levels.

Using the driving waveform shown in Figure 6, the image quality is verified through multiple sets of experiments. First load a picture on the screen, and then use the driving waveform shown in Figure 6 and the traditional driving waveform shown in Figure 7 to refresh the picture to a white grayscale, so as to study the process of refreshing the image with the two driving waveforms Ghosting phenomenon in .

The original picture is a picture with a white background and black fonts. The driving waveform shown in Figure 6 is used to refresh the original picture to a white grayscale. The background brightness value of the original picture is 64.9ints, and the brightness value of the ghost image that appears is 62.5ints. . Using the traditional driving waveform shown in Figure 7 to refresh the original image to a white grayscale, the background brightness value of the original image is 64.5ints, and the ghost image brightness value is 58.7ints. This shows that the ghosting of the image can be reduced by using the driving waveform as shown in FIG. 6 .

The uniformity of the picture is analyzed by calculating the entropy value of the picture and the variance of the gray value of the picture. Referring to Table 1, it shows the changes of entropy and gray value variance when the original image is refreshed to a white gray level using the driving waveform shown in FIG. 6 and the conventional driving waveform shown in FIG. 7 respectively. As shown in Table 1, using the driving waveform shown in Figure 6 to refresh the original image to white grayscale, the entropy value change rate is -6.247%, and the gray value variance change rate is -79.695%; The traditional driving waveform refreshes the original image to white gray scale, the entropy value change rate is -5.706%, and the gray value variance change rate is -79.322%. This shows that compared with the traditional driving waveform, using the driving waveform shown in Figure 6, the image texture is reduced by 0.541%, and the image uniformity is improved by 0.373%.

Table 1 Changes of entropy value and variance of gray value

Through several experiments in Embodiment 2 of the present application, it is fully proved that the driving method of the embodiment of the present application can optimize the activated particle stage and reduce the 280ms driving time of the activated particle stage without affecting the image quality.

Example 3

Referring to FIG. 8 , a block diagram of a module of a specific embodiment of a driving apparatus for an electrophoretic display in an embodiment of the present application is shown. As shown in FIG. 8 , the driving device of the electrophoretic display according to the embodiment of the present application includes a data acquisition module and a waveform driving module; the data acquisition module is connected to the waveform driving module; the data acquisition module is used to record the brightness value of the electrophoretic display that changes over time; The waveform driving module is used to obtain a driving waveform, and the driving waveform includes a first voltage signal, a second voltage signal and a third voltage signal; the first voltage signal is used to refresh the grayscale of the original image to the initial grayscale, and the second voltage signal is used for For refreshing the initial gray scale to the reference gray scale, the third voltage signal is used to write the gray scale of the new image; the waveform driving module is further used for setting the time length of the second voltage signal according to the luminance value.

The waveform driving module is used to apply the driving voltage to refresh the initial gray scale to the reference gray scale, so that the distribution of charged particles in the microcapsules is unified, which is conducive to the more regular and accurate display of the next gray scale, and can reduce ghosting. Setting the time length of the driving voltage according to the brightness value collected by the data acquisition module can reduce the time length of the driving waveform without affecting the display quality, thereby improving the response speed of the EPD.

In other embodiments of the present application, the second voltage signal includes: a positive voltage signal of a first time length and a negative voltage signal of a second time length; the first time length is corresponding to the change rate of the luminance value reaching a maximum value time length; the second time length is the time length corresponding to the refresh to the reference gray level.

The time length corresponding to the change rate of the brightness value of the electrophoretic display reaching the maximum value is set as the first time length, that is, after the voltage driving of the first time length, the activity of the particles reaches the highest state, that is, it is close to the optical limit state. Starting to drive the voltage for the second time length, it is easier to refresh to a stable reference gray scale.

Example 4

A waveform generator according to an embodiment of the present application is used to generate a driving waveform, where the driving waveform includes a first voltage signal, a second voltage signal and a third voltage signal; the first voltage signal is used to refresh the grayscale of an original image to an initial state gray scale, the second voltage signal is used to refresh the initial gray scale to the reference gray scale, and the third voltage signal is used to write the gray scale of the new image; the waveform generator is also used to set the second voltage according to the brightness change of the electrophoretic display The time length of the signal.

A driving voltage is applied to refresh the initial gray scale to the reference gray scale, so that the distribution of charged particles in the microcapsules is unified, which is conducive to more regular and accurate display of the next gray scale, and can reduce ghosting. Applying a voltage with a set time length according to the brightness change of the electrophoretic display can reduce the time length of the driving waveform without affecting the display quality, thereby improving the response speed of the EPD.

In other embodiments of the present application, the second voltage signal includes: a positive voltage signal of a first time length and a negative voltage signal of a second time length; the first time length is when the rate of change of the luminance value of the electrophoretic display reaches a maximum value The corresponding time length; the second time length is the time length corresponding to the refresh to the reference gray level.

The time length corresponding to the change rate of the brightness value of the electrophoretic display reaching the maximum value is set as the first time length, that is, after the voltage driving of the first time length, the activity of the particles reaches the highest state, that is, it is close to the optical limit state. Starting to drive the voltage for the second time length, it is easier to refresh to a stable reference gray scale.

The embodiments of the present application have been described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned embodiments, and within the scope of knowledge possessed by those of ordinary skill in the art, various aspects can also be made without departing from the purpose of the present application. kind of change. Furthermore, the embodiments of the present application and features in the embodiments may be combined with each other without conflict.

In the several embodiments provided in this application, it should be understood that the disclosed technical content may be implemented in other ways. The system embodiments described above are only illustrative, for example, the division of the modules may be a logical function division, and there may be other division methods in actual implementation, for example, multiple units or modules may be combined or Integration into another system, or some features can be ignored, or not implemented.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated units may be implemented in the form of hardware, or may be implemented in the form of software functional units.

The integrated unit, if implemented in the form of a software functional unit and sold or used as an independent product, may be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application can be embodied in the form of software products in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, and the computer software products are stored in a storage medium , including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes .

Claims (7)

1. A driving method for an electrophoretic display, wherein the method comprises: Refresh the grayscale of the original image to the initial grayscale; obtaining a voltage signal of a preset time length, and refreshing the initial grayscale to a reference grayscale; the time length is set according to the change in brightness of the electrophoretic display; Write the grayscale of the new image; The voltage signal includes: a positive voltage signal of a first time length and a negative voltage signal of a second time length; Setting the first time length according to the brightness change of the electrophoretic display includes: acquiring the positive voltage signal, starting to refresh the initial grayscale, and recording the luminance value of the electrophoretic display that changes with time; Calculate the rate of change of the luminance value, and record the time length corresponding to the rate of change reaching the maximum value; setting the length of time to the first length of time; Setting the second time length according to the brightness change of the electrophoretic display includes: acquiring the negative voltage signal, and recording the luminance value of the electrophoretic display that changes with time; The length of time corresponding to the record refresh to the reference grayscale; The time length is set as the second time length. 2. The method for driving an electrophoretic display according to claim 1, wherein the initial grayscale comprises any one of the following four types: black grayscale, dark grayscale, light grayscale and white grayscale order; The reference grayscale is a white grayscale. 3 . The driving method of an electrophoretic display according to claim 1 , wherein the first time length is 60 ms, and the second time length is 140 ms. 4 . 4. A driving device for an electrophoretic display, wherein the device comprises a data acquisition module and a waveform driving module; the data acquisition module is connected to the waveform driving module; The data acquisition module is used to record the brightness value of the electrophoretic display that changes with time; The waveform driving module is used to obtain a driving waveform, and the driving waveform includes a first voltage signal, a second voltage signal and a third voltage signal; the first voltage signal is used to refresh the grayscale of the original image to the initial grayscale , the second voltage signal is used to refresh the initial grayscale to a reference grayscale, and the third voltage signal is used to write the grayscale of the new image; The waveform driving module is further configured to set the time length of the second voltage signal according to the brightness value. 5. The driving device of an electrophoretic display according to claim 4, wherein the second voltage signal comprises: a positive voltage signal of a first time length and a negative voltage signal of a second time length; The first time length is the time length corresponding to the change rate of the luminance value reaching the maximum value; The second time length is the time length corresponding to the refresh to the reference gray level. 6. A waveform generator, characterized in that the waveform generator is used to generate a driving waveform, the driving waveform comprising a first voltage signal, a second voltage signal and a third voltage signal; the first voltage signal is used for Refreshing the grayscale of the original image to the initial grayscale, the second voltage signal is used to refresh the initial grayscale to the reference grayscale, and the third voltage signal is used to write the grayscale of the new image; The waveform generator is also used for setting the time length of the second voltage signal according to the brightness change of the electrophoretic display. 7. The waveform generator according to claim 6, wherein the second voltage signal comprises: a positive voltage signal of a first time length and a negative voltage signal of a second time length; The first time length is the time length corresponding to the change rate of the luminance value of the electrophoretic display reaching the maximum value; The second time length is the time length corresponding to the refresh to the reference gray level.

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