WO2023216350A1

WO2023216350A1 - Method for high gray level electrowetting display device based on cooperation of voltage modulation and time modulation

Info

Publication number: WO2023216350A1
Application number: PCT/CN2022/097508
Authority: WO
Inventors: 林志贤; 梅婷; 林珊玲; 郭太良; 张永爱; 林坚普; 赵敬伟; 费千懿; 王利翔; 吴宇航
Original assignee: 福州大学
Priority date: 2022-05-12
Filing date: 2022-06-08
Publication date: 2023-11-16
Also published as: CN114898716B; CN114898716A

Abstract

The present invention provides a method for a high gray level electrowetting display device based on cooperation of voltage modulation and time modulation. The method comprises: firstly, quantizing inputted image data into n-bit quaternary; dividing a row display period T into n sub-periods, and weighting the sub-periods; assigning four different voltage amplitudes to a display unit within a same sub-period, voltage amplitudes of the sub-periods being different and in a certain multiple relationship; and sequentially displaying all the sub-periods bit by bit within display time of the row display period T to form 4n brightness gray levels. According to the present invention, by means of the advantage of a low response speed requirement for a driving circuit and the display device by using amplitude modulation, the defect that the display quality is reduced due to the fact that the display device cannot respond to too narrow pulses when PWM modulation is used in electrowetting is overcome; moreover, by means of the advantage of easy implementation of the driving circuit by using the PWM modulation, the defect that a circuit is complex by using the amplitude modulation in electrowetting is overcome, and a display effect of a higher gray level of electrowetting electronic paper is achieved.

Description

Method for high grayscale electrowetting display device based on synergy of voltage modulation and time modulation

Technical field

The invention belongs to the technical field of electrowetting display devices, and in particular relates to a method for high grayscale electrowetting display devices based on the synergy of voltage modulation and time modulation.

Background technique

The principle of an electrowetting display is to change the wettability of the ink on the substrate by changing the voltage between the ink and the insulating substrate, changing the contact angle, causing the ink to deform and generate displacement. This principle is used to make a successful electrowetting display. Compared with LCD, LED and other displays, wet displays have the advantages of fast response speed, no need for backlight, low power consumption, high brightness, can still be viewed under strong light, and no viewing angle restrictions. Therefore, electrowetting displays have broad application prospects.

technical problem

As a new type of display, electrowetting displays have attracted widespread attention from domestic and foreign scholars. However, most of the research focuses on electrowetting device structures, ink materials, drive systems, etc. Research on grayscale display technology is in electrowetting. Important content of display technology research. Since the early electrowetting display devices were mainly used for text and image display and had low grayscale requirements, the grayscale levels that the driver chips designed by major companies could drive were also relatively low. However, nowadays, electrowetting electronic paper displays are developing in the direction of "high color image quality", "video playback" and "low power consumption", and low grayscale levels no longer meet the display quality requirements. At present, most of the driving waveform driving method designs can achieve the highest gray level of 64, and there is no method to achieve higher gray levels. Therefore, in order to enrich dynamic video display and further optimize the display quality of electrowetting electronic paper, it is necessary to invent a new method for high grayscale display of electrowetting electronic paper displays.

Technical solutions

In view of the defects and shortcomings of the existing technology, the purpose of the present invention is to provide a method for high-grayscale electrowetting display devices based on the synergy of voltage modulation and time modulation, which can achieve higher electrowetting of electronic paper by using existing chips. Grayscale display effect. It first quantizes the input image data into n-bit quaternary, divides the line display period T into n sub-periods, and weights each sub-period at the same time, giving the display unit four different voltage amplitudes in the same sub-period. , the voltage amplitude of each sub-period is different, and is in a certain multiple relationship. During the display time of the row display period T, each sub-period is displayed bit by bit, forming a brightness grayscale of 4n. The present invention can use amplitude modulation to have the advantage of low response speed requirements for the driving circuit and the display device, and make up for the reduced display quality caused by the inability of the display device to respond to too narrow pulses when using PWM modulation for electrowetting. At the same time, it can be easily realized through PWM modulation of the driving circuit. The advantages of electrowetting make up for the shortcomings of complex amplitude modulation circuits used in electrowetting, and achieve higher grayscale display effects of electrowetting electronic paper.

The present invention specifically adopts the following technical solutions:

A method for high-gray-scale electrowetting display devices based on the synergy of voltage modulation and time modulation, which is characterized by: quantizing the input image data, dividing the line display period T into n sub-periods, and simultaneously measuring each sub-period Weighting, in the same sub-period, gives the display unit four different voltage amplitudes. The voltage amplitudes of each sub-period are different and in a certain multiple relationship. During the display time of the row display period T, each sub-period is sequentially bit by bit. Display, composed of 4n brightness grayscale.

Further, the quantizing the input image data specifically includes: quantizing the input binary grayscale data into equivalent n-bit quaternary data.

Further, the weight used for weighting each sub-period is: T1:T2:T3:...:Tn-1:Tn=1:1:1:...:1:2.

Further, the four different voltage amplitudes assigned to the display unit are specifically: each sub-period has four amplitudes, wherein the first amplitude is the reference voltage, which is determined by the device operating voltage.

Furthermore, the area of the product of voltage amplitude and time in each sub-period is four times the corresponding area of the previous sub-period.

Further, the bit-by-bit display is specifically: according to the line-by-line driving method of electrowetting, a line scan is performed in one sub-period, and a corresponding amplitude voltage is applied in the first sub-period to display the first bit. Data, and so on, after scanning a row n times, n-bit grayscale data is displayed bit by bit, and then the second row is scanned. After the entire image is scanned, a 4n grayscale image is displayed.

beneficial effects

Compared with the existing technology, the present invention and its preferred solutions can expand the display effect of gray levels. For example, when the existing chip can only achieve a maximum of 64 gray levels, the present invention can achieve a display effect of 256 and higher gray levels.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments:

Figure 1 is a driving waveform diagram of an embodiment of the present invention;

Figure 2 is a partial grayscale driving waveform diagram according to an embodiment of the present invention;

Figure 3 is a schematic diagram 1 of the grayscale levels that can be achieved according to the embodiment of the present invention;

Figure 4 is a schematic diagram 2 of the gray levels that can be achieved according to the embodiment of the present invention.

Embodiments of the invention

The technical solutions in the present invention will be clearly and completely described below through examples. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than comprehensive embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without any creative work shall fall within the scope of protection of the present invention.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meanings commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, the singular forms are also intended to include the plural forms unless the context clearly indicates otherwise. Furthermore, it will be understood that when the terms "comprises" and/or "includes" are used in this specification, they indicate There are features, steps, operations, means, components and/or combinations thereof.

As shown in Figure 1, this embodiment provides a method for high-grayscale electrowetting display devices based on the synergy of voltage amplitude modulation and time modulation. The method first quantizes the input image data into n-bit quaternary, The row display period T is divided into n sub-periods, and each sub-period is weighted at the same time. Within the same sub-period, the display unit is given four different voltage amplitudes. The voltage amplitudes of each sub-period are different and have a certain multiple relationship. During the display time of the line display period T, each sub-period is displayed bit by bit in sequence, forming a brightness grayscale of 4n.

Preferably, the weight of the divided sub-periods is T1:T2:T3:...:Tn-1:Tn=1:1:1:...:1:2.

As a preference, in this embodiment, the amplitude of each display unit is set as follows: each sub-period has four amplitudes, the first amplitude is all 0V, and the remaining three amplitudes have proportions as shown in the table below (in 256 grayscale as an example):

Preferably, in this embodiment, the area of the product of voltage amplitude and time in each sub-period is four times the previous area, as shown in the following table (taking 256 grayscale as an example):

As shown in Figure 2 is a schematic diagram of the driving waveforms of some gray levels (such as

gray levels

30, 40, 91, 162, etc.).

In this embodiment, the bit-by-bit display is a line-by-line driving method based on electrowetting. One line scan is performed in one sub-period, and a corresponding amplitude voltage is applied in the first sub-period to display the first bit. Data, and so on, after scanning a row n times, n-bit grayscale data is displayed bit by bit, and then the second row is scanned. After the entire image is scanned, a 4n grayscale image can be displayed. In this embodiment, as shown in Figure 3 and Figure 4, assuming that eight-bit binary data is input, a display period is divided into four sub-periods. After the superposition of each sub-period, its area is proportional to the gray scale. After exhaustive Verification, the gray scale after verification can reach 256 types.

Those skilled in the art will understand that embodiments of the present application may be provided as methods, systems, or computer program products. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment that combines software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each process and/or block in the flowchart illustrations and/or block diagrams, and combinations of processes and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing device produce a use A device for realizing the functions specified in one process or multiple processes of the flowchart and/or one block or multiple blocks of the block diagram.

These computer program instructions may also be stored in a computer-readable memory that causes a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction means, the instructions The device implements the functions specified in a process or processes of the flowchart and/or a block or blocks of the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device, causing a series of operating steps to be performed on the computer or other programmable device to produce computer-implemented processing, thereby executing on the computer or other programmable device. Instructions provide steps for implementing the functions specified in a process or processes of a flowchart diagram and/or a block or blocks of a block diagram.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any skilled person familiar with the art may make changes or modifications to equivalent changes using the technical contents disclosed above. Example. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the protection scope of the technical solution of the present invention.

This patent is not limited to the above-mentioned best implementation. Under the inspiration of this patent, anyone can come up with various other forms of methods for high-grayscale electrowetting display devices based on the synergy of voltage modulation and time modulation. Equal changes and modifications made to the patentable scope of an invention shall be covered by this patent.

Claims

A method for high-gray-scale electrowetting display devices based on the synergy of voltage modulation and time modulation, which is characterized by: quantizing the input image data, dividing the line display period T into n sub-periods, and simultaneously measuring each sub-period Weighting, in the same sub-period, gives the display unit four different voltage amplitudes. The voltage amplitudes of each sub-period are different and in a certain multiple relationship. During the display time of the row display period T, each sub-period is sequentially bit by bit. Display, composed of 4n brightness grayscale.
The method of high grayscale electrowetting display device based on the cooperation of voltage modulation and time modulation according to claim 1, characterized in that: the quantization of the input image data is specifically: quantization of the input binary grayscale data It is equivalent n-digit quaternary data.
The method of high grayscale electrowetting display device based on the synergy of voltage modulation and time modulation according to claim 1, characterized in that: the weight used for weighting each sub-period is: T 1 : T 2 : T 3 :…:T n-1 :T n =1:1:1:…:1:2.
The method for a high-grayscale electrowetting display device based on the synergy of voltage modulation and time modulation according to claim 1, characterized in that: giving the display unit four different voltage amplitudes is specifically: each sub-period has four amplitudes, among which the first amplitude is the reference voltage, which is determined by the device operating voltage.
The method for high-grayscale electrowetting display devices based on the synergy of voltage modulation and time modulation according to claim 4, characterized in that: the product area of voltage amplitude and time in each sub-period is the area corresponding to the previous sub-period. Four times.
The method of high grayscale electrowetting display device based on the synergy of voltage modulation and time modulation according to claim 1, characterized in that: the bit-by-bit display is specifically: according to the line-by-line driving mode of electrowetting, one sub-pixel A line scan is performed once per cycle, and a corresponding amplitude voltage is applied in the first sub-period to display the first bit of data. By analogy, after scanning a line n times, n-bit grayscale data is displayed bit by bit. When scanning the second line, after scanning the entire image, a 4n grayscale image will be displayed.