CN105575336A - Self generation method of driving waveform for electrophoresis display equipment - Google Patents

Abstract

The invention discloses a self generation method of a driving waveform for electrophoresis display equipment. The self generation method comprises calculating the luminance value of each gray scale; gradually increasing the positive voltage or negative voltage time length applied to a pixel electrode from the previous state to form a new driving waveform; driving the electrophoresis display equipment to display images and measure the luminance values; acquiring the luminance values and feeding back the luminance values to a control unit; determining whether the effect of the driving waveform is the required result by means of the control unit; if achieving the expected effect, saving the driving waveform and continuing operation to generate driving waveforms which are transformed from other states; and if not achieving the expected effect, generating a new driving waveform by continuously increasing the time length of positive voltage or negative voltage. The self generation method of a driving waveform for electrophoresis display equipment has the advantages of liberating the labor force and improving the work efficiency through automatic operation of the computer. The generated driving waveform is adaptive to the environment and hardware conditions so that the display effect is better. Compared with a traditional driving waveform, the high frequency driving mode enables human eyes to enjoy higher comfort degree.

Description

A method for self-generating driving waveforms of electrophoretic display devices

technical field

The invention relates to the technical field of displays, in particular to a method for generating driving waveforms of electrophoretic display devices.

Background technique

Microcapsule electrophoretic display technology is currently the most mainstream electronic paper display technology on the market. Compared with other display technologies, it has the advantages of low energy consumption and low manufacturing cost. There are two kinds of charged particles, black and white, in the microcapsules. White particles are positively charged and black particles are negatively charged. When driven by voltages of different polarities, the black and white particles move under the action of the electric field force, resulting in various gray scales from black to white that can be observed by the human eye.

The current design of the driving waveform required by the electrophoretic display device is done manually, the design process is cumbersome, and continuous design is required; if it is completed intermittently, once the external conditions change, the overall design results obtained will deviate greatly. For the design of more gray-scale driving waveforms, the difficulty and time consumption rate of manual design are even higher.

Electrophoretic display devices also have a very distinctive feature that is highly sensitive to the environment and temperature. At different ambient temperatures, the motility of black and white particles and the viscosity of the solution are different, resulting in the need to manually design multiple sets of driving waveforms at different temperatures for calling. At the same time, because the manual design does not design the driving waveform under all temperature conditions, it is only an approximate value within a certain range, so that the adaptation of the driving waveform to the external environment can only be unsatisfactory.

Contents of the invention

In order to solve the above technical problems, the object of the present invention is to provide a method for self-generating driving waveforms of electrophoretic display devices that can intelligently adapt to different environments and have good display effects.

The technical scheme adopted in the present invention is:

A method for self-generating driving waveforms of electrophoretic display devices, comprising steps: S1, the step of collecting extreme display state data, driving from the initial state of the display device to black extreme state and white extreme state, respectively collecting brightness values of the two extreme states; S2 , the calculation step is to calculate the brightness value of each gray scale according to the brightness values of the two extreme states; S3, the step of generating a new driving waveform is to gradually increase the driving positive voltage or The duration of the negative voltage generates a new driving waveform; S4, the driving step, using the driving waveform described in step S3 to drive the electrophoretic display device to display; S5, the measurement step, measuring the brightness value displayed by the display device; S6, the feedback step, Collect the luminance value described in step S5 and feed it back to the control unit; S7, judging step, the control unit judges whether the luminance value described in step S6 is the target luminance value, if so, save the driving waveform described in step S3, otherwise repeat the steps S3 to S7.

Preferably, the step S1 specifically includes sub-steps: S11, the electrophoretic display device applies a positive voltage or a negative voltage to the pixel electrode for a period of time from the initial state, and stops driving when the black extreme state or the white extreme state is stable; S12, obtain After stabilizing the black extreme state and the white extreme state, use a colorimeter to measure or use a camera to obtain pictures corresponding to the two extreme states of black, white and gray respectively, perform AD conversion on the picture and analyze the brightness values of the two extreme states.

Preferably, the step S2 specifically includes a sub-step: S21, calculating the difference ΔL* between adjacent gray scales through the formula

ΔL*=(WL*-BL*)/m

Calculated, where m is the total number of gray scales required minus 1, WL* is the brightness value corresponding to the extreme state of white, and BL* is the brightness value corresponding to the extreme state of black; S22, the brightness value L* of each gray scale is obtained by the formula

L*=BL*+n*（ΔL*）

to calculate, where n represents the desired grayscale number.

Preferably, the step S3 is specifically:

S31, displaying the step of activating and erasing the previous state of the particles, giving a high-frequency pulse voltage from the previous state to drive the display of the display device to a mixed state;

S32, the step of generating and displaying the driving waveform of the next state is to gradually increase the duration of driving the positive voltage or the negative voltage according to the luminance value of the mixed state and the luminance value of the target state to generate a new driving waveform.

Preferably, the high-frequency pulse voltage in step S31 is a pulse voltage higher than 25 Hz.

Preferably, the step S32 is specifically: according to the luminance value of the mixed state and the luminance value of the target state, gradually increase the duration of driving the positive voltage or the negative voltage whose peak value is respectively plus or minus 15V, that is, pass from the mixed state to different Combine the positive and negative 15V voltage for a long time to generate a new driving waveform.

Preferably, the step S6 specifically includes: collecting the luminance value mentioned in the step S5 and feeding it back to the control unit through the UART serial port.

The beneficial effects of the present invention are:

Through the method of automatically generating the driving waveform, the present invention liberates the manual labor and improves the work efficiency through the automatic operation of the computer; at the same time, the self-adaptive environment and the hardware status of the electrophoretic display device during design make the designed driving waveform more match the external conditions , the displayed effect is optimized.

In addition, the driving time of the driving waveform used in the present invention is shorter than that of the conventional driving waveform. And the traditional driving waveform has four stages, which will produce 4 times of flicker that can be detected by the human eye, while the driving waveform in the present invention uses a high-frequency pulse voltage in the part of erasing the image and activating the black and white particles. The flickering in this part is human Undetectable to the naked eye, only one flicker occurs in the drive section. Therefore, the number of flickers is reduced, and the viewing comfort of human eyes is also improved.

The invention can be widely applied to various electrophoretic display devices.

Description of drawings

The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is a schematic diagram of driving waveform design of an embodiment of the present invention;

Fig. 2 is a schematic flow chart of an embodiment of the present invention.

detailed description

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

As shown in Figure 2, the present invention is used to automatically generate driving waveforms for adaptive electrophoretic display devices in any environment from 0°C to 50°C (the operating temperature of the electrophoretic display screen), including:

The step of collecting extreme display state data is to drive from the initial state of the display device to the extreme black state and the extreme white state, and respectively collect brightness values;

The calculation step is to calculate the brightness value of each gray scale with a formula according to the brightness values of the two extreme states;

Generating a new driving waveform step, gradually increasing the length of time of the positive voltage or negative voltage applied to the pixel electrode from the previous state to form a new driving waveform;

The step of driving and measuring, driving the electrophoretic display device to display and measure the brightness value;

A feedback step, collecting and feeding back the brightness value to the control unit;

In the judging step, the control unit judges whether the effect displayed by the driving waveform is the desired result. If it meets the expectation, it will save the driving waveform and continue to run to generate other driving waveforms for state change. If it does not meet the expectation, continue to increase the positive or negative voltage. to generate a new driving waveform;

The cycle operation step, the control unit loads a new driving waveform, and returns to the driving step to continue running;

At the end of the step, the overall design of the required driving waveform is completed, and the complete data of the driving waveform is saved.

On the basis of the above technical solutions, the present invention can also be improved as follows.

Further, in the method for self-generating driving waveforms of electrophoretic display devices, the step of collecting extreme state data includes:

The electrophoretic display device applies a period of positive or negative voltage to the pixel electrode from the initial state, and stops driving when the black extreme state or the white extreme state is stable.

After obtaining the stable black extreme state and white extreme state, use a colorimeter to measure or obtain pictures with a common camera for AD conversion analysis to obtain the brightness value.

Further, the calculation step of the driving waveform self-generation method of the electrophoretic display device uses the formula, ΔL*=(white L*-black L*)/m to calculate the difference between adjacent gray levels, where m is the required gray level The total number is minus 1; then the brightness value of each gray scale is calculated by the formula, L*=black L*+n*(ΔL*), n represents the required gray scale number.

Further, in the method for self-generating driving waveforms of an electrophoretic display device, the generated new driving waveforms include:

Display the particle activation and erasing of the previous state part, give a high-frequency pulse voltage from the previous state, the high-frequency pulse voltage is a pulse voltage higher than 25Hz, the peak value is plus or minus 15V, respectively, and the drive reaches a mixed state .

Drive to display the next state part, and drive to the next display state from the mixed state by applying positive and negative 15V voltages with different combination durations.

Further, in the step of driving display and measuring in the self-generating method for driving waveforms of an electrophoretic display device, the electrophoretic display device is driven by hardware to display gray scales according to the automatically generated driving waveforms, and the displayed brightness value is measured. The measurement step can be colorimeter measurement or other ordinary cameras to acquire pictures for brightness value analysis.

Furthermore, in the feedback step in the self-generating method of driving waveforms for the electrophoretic display device, feeding back the brightness value data to the control unit is accomplished through UART serial port communication.

Further, each step in the method for self-generating driving waveforms of an electrophoretic display device runs sequentially, and iteratively runs before the expected overall driving waveform design is completed, during which the required driving waveforms will be data storage.

Furthermore, the mixed state in the self-generating method of driving waveforms for electrophoretic display devices is an uncertain state and cannot be predicted. Different from the concept of reference gray scale and intermediate state in the traditional driving waveform design, the method of the present invention automatically searches out the required driving waveform through the method of matching the brightness value of the given target gray scale by the computer without manual intervention search process.

The implementation process of the present invention will be described in detail below by taking the generation of four-level grayscale driving waveforms as an example.

Fig. 1 is a schematic diagram of driving waveform design of a specific embodiment of the present invention, as shown in Fig. 1, driving waveform comprises two stages in this specific embodiment: 1, erasing previous state image and activating black and white particle activity, 2, driving to the target grayscale state.

In the first stage, a group of high-frequency pulse signals is used to erase the image of the previous stage and quickly increase the movement activity of black and white particles. Since the pulse signal is a square wave signal and the frequency is higher than 25HZ, which is greater than the frequency that the human eye can perceive, The resulting flicker is invisible to the human eye, reducing flicker in electrophoretic displays.

Phase 2 drives from the blend state after phase 1 ends to the next image state.

The image information of the mixed state obtained after the first stage is unpredictable, which is different from the method of obtaining a specific reference gray scale in the traditional driving waveform. This can also reduce the driving time and improve the response speed of the electrophoretic display to display images.

The data results are obtained by colorimeter measurement or image acquisition by ordinary cameras for AD conversion and analysis of brightness value information. Then the data result is transmitted to the control unit through the UART serial port communication, and the control unit judges whether the brightness value result matches the brightness value of the gray scale required in the overall driving waveform design.

If it matches, then save the driving waveform data under this state transition, and judge whether the design of the overall driving waveform is completed, and return to the step of generating a new driving waveform to continue running if it is not completed, and end when it is completed, and the design of the overall driving waveform is completed;

If not, go back to the step of generating a new driving waveform and continue running.

Fig. 2 is a schematic flow chart of an electrophoretic display device driving method of the present invention. As shown in Fig. 2, a self-generating method of an electrophoretic display device driving waveform of the present invention is used for operating at 0°C to 50°C (the operating temperature of the electrophoretic display screen) Automatically generate the driving waveform of the adaptive electrophoretic display device in any environment; the method includes: (taking the fourth-order driving waveform design as an example)

The step of collecting extreme display state data is to drive from the initial state of the display device to the extreme black state and the extreme white state, for example, the brightness values of the extreme black state and the extreme white state are collected to be 80 and 200 respectively;

The calculation step is to calculate the brightness value of each gray scale according to the brightness values of the two extreme states, for example, in the case of four gray scales, then

ΔL*=(WL*-BL*)/m=(200-80)/3=40;

The brightness value of each gray scale is calculated by the formula

L*=BL*+n*（ΔL*）

to calculate, for example:

Light gray (gray scale number 2) L*=80+2*40=160;

Dark gray (gray scale number 1) L*=80+1*40=120.

In the step of generating a new driving waveform, gradually increase the length of the positive voltage or negative voltage applied to the pixel electrode from the previous state to form a new driving waveform; if the previous state is a white state, first drive a positive 15V voltage for 20MS to obtain The brightness value is 178, which is not part of any brightness value that we need gray scale. Increase the driving time to 40MS, and get a brightness value of 120, which matches the brightness value of dark gray we need. Record the driving waveform for the transition from white state to dark gray state. The length of the driving part is 40MS; at the same time, the brightness of light gray is required The value is 160, and the grayscale brightness value obtained by driving the positive 15V voltage for 40MS is less than this value, then add a negative 15V voltage for 20MS to the pixel electrode, and the grayscale brightness value obtained at this time is 145, which is also smaller than the required brightness value, and continue to increase ; Use this method to run the matching repeatedly, and the driving part of the driving waveform from the white state to the light gray state is a positive 15V voltage of 40MS plus a negative 15V voltage of 80MS and a positive 15V voltage of 40MS. In the same way, the driving waveforms when the states of each gray level are switched mutually can be obtained.

At the end of the step, the overall design of the required driving waveform is completed, and the complete data of the driving waveform is saved.

The entire design process of the present invention is the automatic operation of the program, which liberates the labor force and improves the work efficiency; at the same time, the design adapts to the environment and the hardware status of the electrophoretic display device itself, so that the designed driving waveform is more matched with the external conditions, and the displayed Effect optimization.

In this embodiment, four-level gray-scale driving waveforms are designed as an example, but the self-generation method of driving waveforms in the present invention is applicable to multi-level gray-scale driving waveforms.

The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the described embodiments, and those skilled in the art can also make various equivalent deformations or replacements without violating the spirit of the present invention. , these equivalent modifications or replacements are all within the scope defined by the claims of the present application.

Claims (7)

1. An electrophoretic display device driving waveform self-generation method, is characterized in that, comprises the steps: S1, the step of collecting extreme display state data, driving from the initial state of the display device to the black extreme state and the white extreme state, respectively collecting the brightness values of the two extreme states; S2, a calculation step, calculating the brightness values of each gray scale according to the brightness values of the two extreme states; S3, the step of generating a new driving waveform is to gradually increase the duration of driving the positive voltage or the negative voltage according to the brightness value of the previous state and the brightness value of the target state to generate a new driving waveform; S4, a driving step, using the driving waveform described in step S3 to drive the electrophoretic display device to display; S5, a measurement step, measuring the brightness value displayed by the display device; S6, a feedback step, collecting the brightness value described in step S5 and feeding it back to the control unit; S7, judging step, the control unit judges whether the luminance value described in step S6 is the target luminance value, if yes, save the driving waveform described in step S3, otherwise repeatedly execute steps S3 to S7. 2. A method for self-generating electrophoretic display device driving waveforms according to claim 1, wherein the step S1 specifically includes sub-steps: S11, the electrophoretic display device applies a positive voltage or a negative voltage to the pixel electrode for a period of time from the initial state, and stops driving when the black extreme state or the white extreme state is stable; S12. After obtaining the stable black extreme state and white extreme state, use a colorimeter to measure or use a camera to obtain pictures corresponding to the two extreme states of black, white and gray scale, perform AD conversion on the picture and analyze to obtain the brightness values of the two extreme states. 3. A method for self-generating driving waveforms of electrophoretic display devices according to claim 1, wherein the step S2 specifically includes sub-steps: S21, calculate the difference ΔL* between adjacent gray scales through the formula ΔL*=(WL*-BL*)/m Calculated, where m is the total number of required gray scales minus 1, WL* is the brightness value corresponding to the white extreme state, and BL* is the brightness value corresponding to the black extreme state; S22, the brightness value L* of each gray scale is passed through the formula L*=BL*+n*（ΔL*） to calculate, where n represents the desired grayscale number. 4. A method for self-generating an electrophoretic display device driving waveform according to claim 1, wherein the step S3 is specifically: S31, displaying the step of activating and erasing the previous state of the particles, giving a high-frequency pulse voltage from the previous state to drive the display of the display device to a mixed state; S32, the step of generating and displaying the driving waveform of the next state is to gradually increase the duration of driving the positive voltage or the negative voltage according to the luminance value of the mixed state and the luminance value of the target state to generate a new driving waveform. 5 . The method for self-generating driving waveforms of electrophoretic display devices according to claim 4 , wherein the high-frequency pulse voltage in step S31 is a pulse voltage higher than 25 Hz. 6. A method for self-generating driving waveforms for electrophoretic display devices according to claim 4, wherein the step S32 is specifically: according to the luminance value of the mixed state and the luminance value of the target state, gradually increasing the peak values to positive and negative respectively. The duration of negative 15V driving positive voltage or negative voltage, that is, from the mixed state, a new driving waveform is generated by giving positive and negative 15V voltages of different combination durations. 7. A method for self-generating driving waveforms for electrophoretic display devices according to any one of claims 1 to 6, wherein said step S6 is specifically: collecting the luminance value described in step S5 and feeding it back to the control via the UART serial port unit.