Electrophoretic display driving method and device

Abstract

The invention discloses an electrophoretic display driving method and device, which can effectively solve the problems of ghosting, edge diffusion, slow refresh rate and the like in the prior art. The method comprises the following steps: acquiring a corresponding relationship between each pixel and a display unit of the display device; obtaining a first binary value corresponding to the gray scale of any pixel in the current frame image; acquiring a second binary value corresponding to the gray scale of the pixel in the next frame of image; groups are established for a preset number of adjacent pixels, and the number of the pixels contained in each group is consistent; assigning an intra-group number to each pixel in the group; generating a first driving waveform lookup table according to the intra-group serial number, the first binary value, the second binary value and the corresponding relation; driving each display unit according to the first driving waveform lookup table; and driving other display units of the display unit in the group according to the first driving waveform lookup table.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic paper display, in particular to a method and device for driving electrophoretic display. BACKGROUND

[0002] Electronic paper display technology is a new type of reflective display mode, which has the advantages of high reflectivity, low power consumption, high contrast and long-term retention compared with traditional display modes, and is a new type of electronic device that can replace paper for reading.

[0003] The main difficulties faced by current electrophoretic display include but are not limited to: ghosting, edge diffusion, slow refresh rate, etc. The inventors found in the front-line research that most of the problems of electrophoretic display are due to the failure to handle the relationship between adjacent pixels on the display screen. The traditional driving is single-point driving, and the mutual influence between electronic paper pixel particles is not considered. The mutual influence of adjacent particles will cause the change of pixels that have not changed, resulting in ghosting. For example, for RGBW, RGB color ink screen, because multiple pixel points are used to represent a color value, the traditional method treats RGBW pixel points as independent pixel points, which is not the most reasonable way. SUMMARY

[0004] The problem to be solved by the present application is the ghosting, edge diffusion, slow refresh rate, etc. in the prior art.

[0005] The present application provides a method for driving electrophoretic display, comprising:

[0006] Obtaining the corresponding relationship between each pixel and the display unit of the display device;

[0007] Obtaining the first binary value corresponding to the gray scale of any pixel in the current frame image;

[0008] Obtaining the second binary value corresponding to the gray scale of the pixel in the next frame image;

[0009] Establishing groups for a predetermined number of adjacent pixels, each group containing a consistent number of pixels;

[0010] Assigning an intra-group number to each pixel in the group;

[0011] Generating a first driving waveform lookup table according to the intra-group number, the first binary value, the second binary value and the corresponding relationship;

[0012] Driving each display unit according to the first driving waveform lookup table;

[0013] Driving the remaining display units of the group according to the first driving waveform lookup table.

[0014] Optionally,

[0015] The step of grouping the predetermined number of adjacent pixels and assigning a group number further comprises:

[0016] Assigning a group number to each group;

[0017] Storing all groups according to the group number.

[0018] Optionally,

[0019] The step of obtaining a first binary value corresponding to the gray scale of any pixel in the current frame image and obtaining a second binary value corresponding to the gray scale of the pixel in the next frame image further comprises:

[0020] Calculating the difference between the second binary value and the first binary value of the pixel;

[0021] Generating a second driving waveform lookup table according to the group number, the difference value and the corresponding relationship.

[0022] Optionally,

[0023] The second driving waveform lookup table comprises a driving waveform corresponding to the difference value one by one.

[0024] The number of non-zero main pulses in the driving waveform is related to the difference value, and the direction corresponds to the sign of the difference value.

[0025] Optionally,

[0026] The main pulse comprises a pulse for driving to a target gray scale error of plus or minus 10 brightness units.

[0027] Optionally,

[0028] Obtaining temperature information:

[0029] Generating a third driving waveform lookup table according to the temperature information, the group number, the difference value and the corresponding relationship.

[0030] Optionally,

[0031] Calculating a pulse direction value according to the second binary value and the first binary value;

[0032] Generating a third driving waveform lookup table according to the pulse direction value, the group number, the difference value and the corresponding relationship.

[0033] Another aspect of the present application provides an electrophoretic display driving device, which applies the electrophoretic display driving method as described above, and the device comprises:

[0034] A first obtaining unit is configured to obtain the corresponding relationship between each pixel and the display unit of the display device;

[0035] A second obtaining unit is configured to obtain a first binary value corresponding to a gray scale of any pixel in a current frame image.

[0036] A third obtaining unit is configured to obtain a second binary value corresponding to the gray scale of the pixel in a next frame image.

[0037] A establishing unit is configured to establish groups for a predetermined number of adjacent pixels, and each group contains a same number of pixels.

[0038] A first allocating unit is configured to allocate an in-group number to each pixel in a group.

[0039] A first generating unit is configured to generate a first driving waveform lookup table according to the in-group number, the first binary value, the second binary value and a corresponding relationship.

[0040] A first driving unit is configured to drive each display unit according to the first driving waveform lookup table.

[0041] A second driving unit is configured to drive the remaining display units of a group according to the first driving waveform lookup table.

[0042] Optionally,

[0043] The apparatus comprises:

[0044] A second allocating unit is configured to allocate a group number to each group.

[0045] A storing unit is configured to store all groups according to the group number.

[0046] Optionally,

[0047] The apparatus comprises:

[0048] A first calculating unit is configured to calculate a difference between the second binary value and the first binary value of the pixel.

[0049] A second generating unit is configured to generate a second driving waveform lookup table according to the in-group number, the difference and the corresponding relationship.

[0050] Optionally,

[0051] The apparatus comprises:

[0052] A fourth obtaining unit is configured to obtain temperature information.

[0053] A third generating unit is configured to generate a third driving waveform lookup table according to the temperature information, the in-group number, the difference and the corresponding relationship.

[0054] Optionally,

[0055] The apparatus comprises:

[0056] a second calculation unit configured to calculate a pulse direction value according to the second binary value and the first binary value;

[0057] a fourth generation unit configured to generate a third driving waveform lookup table according to the pulse direction value, the in-group number, the difference value and the corresponding relationship.

[0058] Compared with the prior art, the present application has the following advantages:

[0059] In the embodiment, N*M pixel points are combined into a matrix, and a driving waveform is generated according to color values represented by the matrix and possible mutual influence relationship between pixels in the matrix to drive the ink screen. The model drives in the matrix waveform mode, considers mutual influence between pixel particles, and can improve afterimage caused by mutual influence between pixel particles. The model uniformly considers meaning represented by multiple pixel particles, and is more suitable for color ink screen driving. BRIEF DESCRIPTION OF DRAWINGS

[0060] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0061] Figure 1 It is a schematic diagram of SDRAM storage structure in the prior art;

[0062] Figure 2 It is a SDRAM storage table in the prior art;

[0063] Figure 3 It is a flowchart of the electrophoretic display driving method embodiment provided by the present application;

[0064] Figure 4 It is a flowchart of another embodiment of the electrophoretic display driving method provided by the present application;

[0065] Figure 5 It is a structural schematic diagram of the electrophoretic display driving device embodiment provided by the present application;

[0066] Figure 6 It is a schematic diagram of the pixel group structure provided by the present application. DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0068] In this document, the term "comprising" is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a process, method, article or device. Without more limitations, the elements defined by the statement "comprising" do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0069] In the embodiments, the electrophoretic display includes an Electro-Phoretic Display (EPD), an Electro-Wetting Display (EWD), a Cholesteric Liquid Crystal Display (CLCD) or other Bi-stable display panel, and the present application is not limited thereto.

[0070] In the embodiments, the core element of the electronic paper film is electrophoretic pigment particles, and the particle size distribution, surface morphology, zeta potential, optical performance and chemical performance of the electrophoretic pigment particles play a key role in the contrast, response time, definition and service life of the electronic paper. The electrophoretic display technology is to stably disperse the charged pigment particles in the non-water system dispersion medium containing dye in colloid chemistry by using the electrophoresis principle, so that the dispersed phase and the dispersion medium present contrast, and under the action of the electric field, the charged pigment ions move to the surface of the electrode to display the image.

[0071] In the present embodiment, the structure of the electrophoretic pigment particle comprises a core and a shell layer, the core is a pigment particle, and the shell layer comprises a high molecular polymer and a coupling agent coupling the high molecular polymer and the pigment particle. The pigment particle comprises a positive pigment particle, a negative pigment particle or a neutral pigment particle, specifically one or more than two combinations of carbon black, copper chromium black, copper iron manganese black, iron black, titanium dioxide, zinc white, barium sulfate, iron oxide red, iron oxide yellow, ultramarine, chromium yellow, cadmium red, intense purple, chromium green, iron blue and cobalt blue. The coupling agent is one or more than two combinations of 3-aminopropyl triethoxysilane (KH550), γ-(2,3-epoxypropoxy) propyl trimethoxysilane (KH560), γ-(methacryloyloxy) propyl trimethoxysilane (KH570), γ-mercaptopropyl trimethoxysilane (KH580), N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane (KH792), vinylbenzyl aminoethyl aminopropyl trimethoxysilane (VAPMS) and isopropyl trioleate titanate. In order to ensure that the average particle size of the above-mentioned electrophoretic pigment particle meets the requirements, the applicant needs to micronize the electrophoretic pigment particle, which can be realized by methods such as grinding, crushing, ultrasonic or solvent dispersion in practical application, and the related equipment can include colloid mill, ball mill, frozen crusher, ultrasonic machine, etc.

[0072] The main components of the electrophoretic fluid include, but are not limited to, dispersing agents, thickening agents, surface tension control agents, and charge control agents. The dispersing agents include various non-polar and / or low-polar organic solvents and mixtures thereof. The low-polar dispersing solvents include, but are not limited to, various aromatic hydrocarbons such as toluene, benzene, xylene, and halogenated hydrocarbons such as, but not limited to, chloroform, tetrachloroethylene, and the like. The non-polar dispersing solvents include, but are not limited to, straight-chain, branched, and cyclic aliphatic hydrocarbons such as n-hexane, nonane, decane, Isopar, Norpar, Nappar, Varsol / Naphtha, cyclohexane, and halogenated hydrocarbons such as carbon tetrachloride. The thickening agents can be non-polar polymers including, but not limited to, polymethyl methacrylate, polyethylene, polypropylene, and rubbers such as polyisoprene, polyisobutylene, and the like, with polymethyl methacrylate, polyisoprene, and polyisobutylene being the preferred choices. In addition, the surface tension control agents can be selected from one or a combination of two or more of glycerol monostearate, ethyl bis-stearyl hydroxyethyl methyl ammonium methosulfate, ethyl tris-stearyl hydroxyethyl methyl ammonium methosulfate, Span 20, Span 40, Span 60, Span 80, Tween 85, and alkyl tertiary amine salts. The charge control agents can be organic sulfates, sulfonates, metal soaps, organic amides, organic phosphates, or phosphates, and can also be polymers and block or graft copolymers and their monomers. Polyisobutylene succinimide, metal soaps, and lecithin polyisobutylene or silicone derivatives can be used as the charge control agents.

[0073] The electrophoretic fluid and the electrophoretic pigment particles dispersed in the electrophoretic fluid are encapsulated in the display unit, thereby effectively inhibiting the agglomeration of the electrophoretic pigment particles and improving the stability and service life of the electrophoretic display. In the present embodiment, the display unit can include at least one of a microcapsule and a microcup. The microcapsule in the present embodiment includes the electrophoretic fluid, the electrophoretic pigment particles dispersed in the electrophoretic fluid, and at least one capsule wall, which is a capsule wall formed by a complex coacervation method or a capsule wall formed by an in-situ polymerization method. It should be noted that the in-situ polymerization can also be referred to as an interfacial polymerization method, and urea-formaldehyde resin or modified urea-formaldehyde resin is used as the microcapsule wall material. In the complex coacervation method, gelatin and gum arabic are used as the microcapsule wall material. The microcup in the present embodiment includes the electrophoretic fluid, the electrophoretic pigment particles dispersed in the electrophoretic fluid, and a microcup. The microcup can be a columnar body with a small size, a cavity, and sealed upper and lower surfaces. The microcup is formed by microcup roll casting and ultraviolet hardening, and the electrophoretic pigment particles in the electrophoretic fluid are encapsulated in the microcup by a specific method.

[0074] The structure of the electrophoretic display in the present embodiment includes, but is not limited to, a display layer containing a curing medium and at least one electrophoretic fluid and electrophoretic pigment particles dispersed in the electrophoretic fluid distributed in the curing medium, and the display layer is connected to a transparent conductive layer by an adhesive.

[0075] One method of preparing the display layer in this embodiment is to mix the transparent adhesive, display unit containing electrophoretic liquid such as microcapsules or microcups, and other solvents in a predetermined ratio, stir the resulting mixture uniformly, and then coat it on the substrate. In actual processing, the mixture can be coated on the substrate by a slot extrusion coating process. The slot extrusion coating process can be that the coating material is pressurized by a quantitative pump and then extruded from the extrusion port of the coating die and coated on the surface of the substrate. The thickness of the coating layer can be determined according to the amount of coating material extruded from the coating die and the running speed of the substrate. The applicant can pre-set the gap of the extrusion port and the distance between the extrusion port and the back roller to control the process. Then solidify, which can be understood as solidification at room temperature. In order to speed up the solidification speed, conventional solidification means such as heating, air drying or photocuring can be used to achieve rapid solidification. It is worth noting that instead of the slot extrusion coating process, other coating methods such as doctor blade coating, flow coating, brushing, rolling, spraying, powder coating, screen printing and inkjet printing can also be used. The adhesive mentioned in this embodiment includes water-based polyurethane emulsion or solvent-based polyurethane emulsion, specifically including but not limited to one or more combinations of polyester diol, polyether diol, polyethylene glycol, small molecule chain extender and diisocyanate. The transparent conductive layer can be ITO (Indium Tin Oxides, Indium Tin Oxide), also known as a semiconductor transparent conductive film, which is obtained by forming a transparent indium tin oxide (ITO) conductive film coating on a transparent organic film material such as PET (Polyethylene terephthalate), PE (polyethylene), PP (polypropylene) and other materials and then annealing at high temperature. The preparation method of ITO transparent conductive film includes but is not limited to evaporation, sputtering, reactive ion plating, chemical vapor deposition or pyrolysis spraying process. In practical applications, graphene, silver powder or nanosilver wire conductive film can be used instead of ITO transparent conductive film. Due to the high advantages of graphene in conductivity and hardness, it is suitable for making conductive film. The preparation method of the graphene conductive film includes but is not limited to chemical vapor deposition and redox method. Chemical vapor deposition can obtain high-quality large-area single-layer graphene, which has performance advantages in light transmittance and surface resistance, but has defects such as complex process route, high cost, low yield and limited film area. The redox method uses a solution process, which is convenient for large-area continuous production by roll-to-roll process and has a great advantage in cost. The silver powder conductive film uses silver conductor paste as the main material, in which the silver powder is used as a conductive functional material, mainly utilizing the conductivity and thermal conductivity of silver powder. Silver powder can be divided into coarse silver powder and nanosilver wire according to particle size, among which the average particle size <0.1 μm is nanosilver wire; 0.1 μmIn addition to the excellent electrical conductivity of silver, the nanosilver wire also has excellent light transmittance and flexibility due to the nanoscale size advantage, and thus can be used as a preferred material to replace ITO. The driving backboard in the present embodiment can be a TFT glass substrate, an FPC, or a segment code glass substrate. When using dot matrix display technology, a TFT glass substrate can be used.

[0076] In the present embodiment, the electrophoretic fluid includes n types of electrophoretic pigment particles C1,..., Ck,..., Cn, n is a natural number of 2 or more, k = n-1, when n = 2, Ck is omitted, the charged particles C1,..., Ck,..., Cn have different colors from each other and different threshold voltages for initiating electrophoresis from each other, and each charged particle C1,..., Ck,..., Cn satisfies the following relationship characteristics: the threshold voltage of the charged particle C1 >... > the threshold voltage of the charged particle Ck >... > the threshold voltage of the charged particle Cn. Wherein k = n-1, when n = 2, the k voltage application period is omitted.

[0077] The voltage application unit is configured to, at the screen update, for each specified voltage drive waveform to be applied, in the order of charged particles C1→...,→Ck→,...,→Cn, in response to the updated relative color density for each type of charged particle, cause the corresponding charged particle to electrophorese along the thickness direction of the electrophoretic layer by a predetermined distance less than or equal to the thickness "L", and finally update the screen to the next screen with a plurality of gray levels more than or equal to three gray levels, wherein if there is no sequence inversion, the given type or multiple types of charged particles can simultaneously transition to the intermediate transition state or the final display state.

[0078] Please refer to Figure 3This embodiment addresses the main difficulties currently faced by electrophoretic displays, including but not limited to: ghosting, edge diffusion, and full refresh rate. During frontline research and development, the developers of this invention discovered that most problems with electrophoretic displays stem from the failure to properly handle the relationships between adjacent pixels on the display screen. Traditional driving methods are single-point driven and do not consider the mutual influence between electronic paper pixel particles. Because the mutual influence of neighboring particles can cause previously unchanged pixels to change, resulting in ghosting. For example, for RGBW and RGB color e-ink screens, since multiple pixels represent a single color value, the traditional method of treating RGBW pixels as independent pixels is not the most efficient approach. This embodiment combines N*M pixels into a matrix. Based on the color value represented by the matrix and the potential mutual influence relationships between the matrix pixels, a driving waveform is generated to drive the e-ink screen. Because this model uses a matrix waveform approach, it considers the mutual influence between pixel particles, thus improving ghosting caused by pixel particle interactions; and it unifies the meaning represented by multiple pixel particles, making it more suitable for color e-ink screen driving.

[0079] The specific embodiments of this method include:

[0080] 101. Obtain the correspondence between each pixel and its display unit on the display device;

[0081] In this embodiment, the processor executes a matching program to obtain the correspondence between each pixel and its display unit on the display device.

[0082] It should be noted that the TFT interlacing, with each intersection point being the display unit, also known in the industry as a pixel. Because this is easily confused with pixels in an image, it is represented by display units in this invention. The image needs to be displayed on the display interface of the electrophoretic display device; therefore, there is a one-to-one correspondence between image pixels and image units. The corresponding image pixels can be recorded in the memory using the coordinates of the display units, or other marking methods, which will not be elaborated upon here.

[0083] 102. Obtain the current frame image. Figure 1 The first binary value corresponding to the gray level of any pixel;

[0084] 103. Obtain the second binary value corresponding to the grayscale of the pixel in the next frame image;

[0085] In this embodiment, please refer to Figure 1 This illustrates a schematic diagram of image data storage in the prior art, such as... Figure 1As shown, SDRAM1 and SDRAM2 are respectively used to store image data of the previous frame and the next frame (the image data of the previous frame and the next frame can also be stored in the same SDRAM, and SDRAM1 and SDRAM2 are respectively represented as two storage areas), in which image data of each pixel is respectively stored, for example, data1, data2,..., and dataN. First, the electronic paper needs to be initialized for display after power-on, so that the subsequent image display has a better reference value. For example, after the display is initialized, the data of SDRAM1 is all set to 0, the first frame image data is stored in SDRAM2, SDRAM2 is compared with SDRAM1 when the first frame image is displayed, the lookup table is queried, and the output is displayed, and at the same time, the first frame image data (the previous frame image relative to the image to be displayed for the second frame after the first frame image is displayed, which is also called the previous frame image data at this time) is stored in SDRAM1; the second frame image data (the next frame image data) is stored in SDRAM2, SDRAM2 is compared with SDRAM1 when the second frame image is displayed, the lookup table is queried, and the output is displayed, and SDRAM1 stores the current image; the image data to be displayed for the next frame is stored in SDRAM2, and the like is sequentially repeated, and the display screen to be displayed can be output by cyclic execution.

[0086] In the embodiment, first, the electrophoretic display combined with RGB filter is taken as an example, and the color particle electrophoretic display application can also be applied to the embodiment. The microcapsule can display black and white colors, and also supports grayscale display mode, such as GC4, GC8 or GC16 mode, wherein GC represents grayscale clear screen refresh, and 4, 8 and 16 represent the maximum number of gray scales supported by different modes. Currently, the ink screen can support 16-level grayscale display, and taking the GC16 mode as an example, the mode provides 16-level grayscale display effect from 0 to 15, 0 corresponds to white, 15 corresponds to black, and 1 to 14 correspond to different gray effects from white to black in turn. Of course, in actual application, there is also a solution to define 0 as black and 15 as white, and the embodiment does not limit this. When displaying each level of grayscale between black and white, the black and white ink particles are no longer driven to the top or bottom of the microcapsule, but are moved and suspended at a certain position in the microcapsule to meet the grayscale display requirement of different gray scales.

[0087] In displaying a frame of image, first, the RGB image is processed to gray scale, and the RGB value of each pixel in the image is converted to a 16-level gray scale value, then the look-up table (LUT) is searched by the time sequence controller circuit to obtain the driving waveform of each pixel, which contains the current / voltage, pulse length, pulse period and other information that the pixel needs to use in displaying the current frame. After receiving all the driving waveforms of the pixels in the current frame, the electronic paper controller drives the microcapsules corresponding to each pixel in the ink screen according to the driving parameters carried by the driving waveform, controls the black and white ink particles in the microcapsules to move from the current position to the next position, so as to refresh the ink screen to display the next frame of image content.

[0088] The LUT table is a driving mapping table of the ink screen obtained and recorded by the ink screen supplier based on the screen hardware test, which records the driving waveform of the pixel corresponding to different display requirements / conditions. The dependent variables in the mapping table usually include: the gray scale value of the pixel in the next frame, the gray scale value of the pixel in the previous frame, and the current screen temperature. The gray scale value of the pixel in the next frame determines the position to which the ink particles should move, and the gray scale value of the pixel in the previous frame corresponds to the current position of the ink particles. The screen temperature needs to be considered because the viscosity of the filling liquid in the microcapsule is different under different temperature conditions. Under the same driving waveform condition, the viscosity of the filling liquid increases, the moving resistance of the ink particles increases, the moving distance of the ink particles is insufficient, which will cause the screen to display too dark or too light, affecting the display effect. Therefore, it is necessary to adjust the driving waveform according to the current screen temperature to ensure that the ink particles can fully move to the specified position under different temperatures, and achieve sufficient and accurate gray scale expression. Usually, the viscosity of the filling liquid is negatively correlated with the temperature, that is, the lower the temperature, the greater the viscosity of the filling liquid.

[0089] In the LUT table, all permutation and combination pairs of the three parameters of "next frame gray scale value", "previous frame gray scale value" and "current screen temperature" are given, and each permutation and combination pair is mapped to a corresponding driving waveform parameter to form the above-mentioned mapping table.

[0090] During the lookup process, the timing controller circuit retrieves the grayscale image of the next frame from the system-on-chip (SOC) and obtains the grayscale value of each pixel. Then, it retrieves the grayscale image of the previous frame from the buffer, similarly obtaining the grayscale value of each pixel in the previous frame. Next, the timing controller circuit queries the SOC for temperature data around the e-ink screen. This data is monitored and transmitted to the SOC by a temperature sensor located inside the terminal and close to the back panel of the e-ink screen. After obtaining the above data, the timing controller circuit uses these three data items as dependent variables and looks up the corresponding drive waveform in the LUT table. Once the drive waveform corresponding to each pixel in a frame of image is obtained, the lookup process is complete.

[0091] 104. Establish groups for a predetermined number of adjacent pixels, with each group containing the same number of pixels;

[0092] 105. Assign a group number to each pixel within the group;

[0093] In this embodiment, as Figure 6 The M*N matrix units are prefixed with detailed information, with an encoding length of log2N bits. For example, (encoding an RGBW sorted color e-ink screen into a 2*2 matrix, with the R component prefixed as b:00, the G component prefix as b:01, the B component prefix as b:02, and the W component prefix as b:03). The group number can be defined as binary, including: R component prefix as b:00, G component prefix as b:01, B component prefix as b:10, and W component prefix as b:11.

[0094] It should be noted that the purpose of setting the group numbers above is to ensure that the group corresponds to the filter, and the pixel corresponds to the color resistance of the filter.

[0095] In this embodiment, the application is not limited to microcapsule filters. The color particle microcapsules, microcuplets, and plasma structures are locally defined. For example, RGB can also be applied to CMYH, i.e., cyan, magenta, yellow, and white. For example, the C component is prefixed with b:00, the M component with b:01, the K component with b:10, and the W component with b:11.

[0096] 106. Generate a first drive waveform lookup table based on the group number, the first binary value, the second binary value, and the corresponding relationship;

[0097] In this embodiment, as shown in the table below:

[0098]

[0099] Table 1 is the grouped LUT table.

[0100] 107. Drive each display unit according to the first drive waveform lookup table;

[0101] 108. driving the rest of the display units in the group according to the first driving waveform lookup table.

[0102] In the embodiment, firstly, the correspondence between each pixel and the display unit of the display device is obtained; the first binary value corresponding to the gray scale of any pixel in the current frame image is obtained; the second binary value corresponding to the gray scale of the pixel in the next frame image is obtained; the three obtaining actions are not sequentially limited; then, a group of a predetermined number of adjacent pixels is established, each group contains the same number of pixels; each pixel in the group is assigned an intra-group number; then, the first driving waveform lookup table is generated according to the intra-group number, the first binary value, the second binary value, and the correspondence; then, each display unit is driven according to the first driving waveform lookup table; the rest of the display units in the group are driven according to the first driving waveform lookup table. The two driving actions are not limited to whether they occur sequentially or simultaneously. In the embodiment, four pixels are taken as a group, and when any one of the pixels is driven, the other pixels in the group are also driven. When a group is taken as a color display unit, the influence between adjacent pixels is considered as an internal problem of the display unit. As each color display unit, the display unit does not affect the display unit. Thus, the problems such as ghosting and edge diffusion caused by the mutual influence of adjacent pixels are effectively solved.

[0103] It should be noted that, considering the general situation of actual application, the above method further includes assigning a group number to each group. All groups are stored according to the group number. It should be noted that the processor can traverse to the group number of the corresponding pixel according to the group number of the display unit, and then determine the intra-group number. Each group is assigned a group number in advance, and all groups are stored according to the group number.

[0104] It should be noted that, considering the general situation of actual application, the above method further includes obtaining temperature information, and generating a second driving waveform lookup table according to the temperature information, the correspondence, and the difference.

[0105] In the embodiment, the screen temperature needs to be considered because the viscosity of the filling liquid in the microcapsule is different under different temperature conditions. Under the same driving waveform condition, the viscosity of the filling liquid increases, the moving resistance of the ink particles increases, the moving distance of the ink particles is insufficient, which will cause the screen display to be too deep or too shallow, and affect the display effect. Therefore, the driving waveform needs to be adjusted according to the current screen temperature to ensure that the ink particles can move to the specified position under different temperatures, and the sufficient and accurate gray scale expression is realized. Generally, the viscosity of the filling liquid is negatively correlated with the temperature, that is, the lower the temperature, the greater the viscosity of the filling liquid.

[0106] The application further provides an electrophoretic display driving method, which is different from the foregoing embodiment in that it further comprises calculating a pulse direction value according to the second binary value and the first binary value; and generating a third driving waveform lookup table according to the pulse direction value, the corresponding relationship and the difference value. The reason why the pulse direction is taken into account is to facilitate knowing whether it is from white driving to black or from black driving to white, and to further improve the driving efficiency.

[0107] Referring to Figure 2 The application provides another embodiment of the electrophoretic display driving method, which aims to solve the problem of too complex driving form and poor data processing and storage efficiency. The embodiment is different from the foregoing embodiment in that it further comprises the following steps after the steps of obtaining the first binary value corresponding to the gray scale of any pixel in a current frame image and obtaining the second binary value corresponding to the gray scale of the pixel in a next frame image: calculating a difference value of the second binary value and the first binary value of the pixel; and generating a second driving waveform lookup table according to the group number, the difference value and the corresponding relationship.

[0108] The foregoing method embodiments will be described below with an example in an actual application, which specifically comprises the following steps:

[0109] 201. Obtaining the corresponding relationship between each pixel and the display unit of the display device;

[0110] 202. Obtaining the first binary value corresponding to the gray scale of any pixel in a current frame image;

[0111] 203. Obtaining the second binary value corresponding to the gray scale of the pixel in a next frame image;

[0112] The steps 201-203 are consistent with the foregoing steps 101-103, and thus will not be described herein.

[0113] 204. Calculating a difference value of the second binary value and the first binary value of the pixel;

[0114] In the embodiment, the processor obtains the driving waveform corresponding to each pixel from the driving waveform lookup table, and the driving waveform corresponding to each pixel in the prior art is a string of binary data with 10-bit new and old gray scale information, as shown in the following table:

[0115]

[0116] Table 2 is a prior art LUT table

[0117] The first two columns from the left contain new and old gray scale information, N0-N4 are 5-bit new image gray scale information, and O0-O4 are 5-bit old image gray scale information. Compared with the prior art, the new and old gray scale information is processed by difference, and a 5-bit gray scale difference is obtained. When processing each pixel, only 5-bit gray scale difference is extracted and processed. The storage space and processing speed are greatly saved.

[0118] 206. Grouping a predetermined number of adjacent pixels, each of the groups containing a consistent number of pixels;

[0119] 207. Assigning an intra-group number to each pixel in the group;

[0120] Steps 206-207 are consistent with steps 104-105, and will not be repeated.

[0121] 208. Generating a second driving waveform lookup table according to the intra-group number, the difference value, and the corresponding relationship;

[0122] 209. Driving each display unit according to the second driving waveform lookup table;

[0123] 210. Driving the remaining display units of the group according to the second driving waveform lookup table.

[0124] In this embodiment, when the processor searches for the driving waveform corresponding to each pixel from the driving waveform lookup table, compared with the prior art, the driving waveform corresponding to each pixel is a string of binary data with 10-bit new and old gray scale information, as shown in the following table:

[0125]

[0126] Table 3 is a prior art LUT table

[0127] The first two columns from the left contain new and old gray scale information, N0-N4 are 5-bit new image gray scale information, and O0-O4 are 5-bit old image gray scale information. Compared with the prior art, the new and old gray scale information is processed by difference, and a 5-bit gray scale difference is obtained. When processing each pixel, only 5-bit gray scale difference is extracted and processed. The storage space and processing speed are greatly saved.

[0128] In the embodiment, in addition to the technical effects of the first embodiment, the first binary value corresponding to the gray scale of any pixel in the current frame image is obtained, and the second binary value corresponding to the gray scale of the pixel in the next frame image is obtained without the limitation of the order; then the difference between the second binary value and the first binary value of the pixel is calculated. By optimizing the data processing method, the data processing process is greatly simplified to improve the efficiency of data processing, and by changing the data storage form of the waveform, the storage space required by the flash memory is reduced, thereby achieving the purpose of reducing the cost.

[0129] In actual application, the four pixels are a group, and when any one of the pixels is driven, the other pixels in the group are also driven. When a group is processed as a color display unit, the influence between adjacent pixels is a problem within the display unit. As each color display unit, the display unit does not affect the display unit. Therefore, the problems such as residual image (ghost) and edge diffusion caused by the mutual influence of adjacent pixels are effectively solved.

[0130] On a 32-bit machine, 4 pixels (a group) are processed at a time, which is more than 5 times faster than the prior art of processing one pixel at a time.

[0131]

[0132] Table 4 is a comparison table of processing speed between the new and old methods

[0133] It should be noted that the second driving waveform lookup table includes a driving waveform corresponding to the difference value; the number of non-zero main pulses in the driving waveform is related to the difference value, and further, the absolute value of the difference value is the same, the number of non-zero main pulses is the same, and the direction of the main pulse is consistent with the sign of the difference value. The above-mentioned main pulse is configured as a pulse driving to a target gray scale error of plus or minus 10 brightness units.

[0134] In the embodiment, the number of main pulses determines the size of the difference between one gray scale and another gray scale. The larger the difference between the gray scales, the more main pulses are needed. The same number of main pulses corresponds to the same difference between the gray scales. Compared with the prior art, only the difference between the gray scales is used to drive the main pulses to drive the main pulses more efficiently. After traversing the main pulses according to the difference, the main pulses can be driven according to the number of main pulses, or the main pulses can be converted into a driving waveform and stored. When driving is needed, the driving waveform is called. In specific embodiments, how to drive according to the main pulses also needs to be determined according to specific factors such as pulse spacing and pulse width.

[0135] Please refer to Figure 5 , the application provides another aspect of an electrophoretic display driving device embodiment,

[0136] including:

[0137] The first obtaining unit 301 is configured to obtain the correspondence between each pixel and the display unit of the display device.

[0138] The second obtaining unit 302 is configured to obtain the first binary value corresponding to the gray scale of an arbitrary pixel in the current frame image.

[0139] The third obtaining unit 303 is configured to obtain the second binary value corresponding to the gray scale of the pixel in the next frame image.

[0140] In the embodiment, the first obtaining unit 301 is configured to obtain the correspondence between each pixel and the display unit of the display device; the second obtaining unit 302 is configured to obtain the first binary value corresponding to the gray scale of an arbitrary pixel in the current frame image; and the third obtaining unit 303 is configured to obtain the second binary value corresponding to the gray scale of the pixel in the next frame image. The three obtaining actions are not limited in sequence. The obtaining results will be described in subsequent embodiments.

[0141] The first calculating unit 304 is configured to calculate the difference between the second binary value and the first binary value of the pixel.

[0142] In the embodiment, the first obtaining unit 301 is configured to obtain the correspondence between each pixel and the display unit of the display device.

[0143] In the embodiment, the processor executes the matching program to obtain the correspondence between each pixel and the display unit of the display device.

[0144] It should be noted that the TFT is interlaced with latitude and longitude, and each intersection point is the display unit, which is also called pixel in the industry. In order to avoid confusion with the pixel in the image, the display unit is used in the present application. The image needs to be displayed on the display interface of the electrophoretic display device, so that the pixel of the image has a one-to-one correspondence with the display unit. The pixel of the image can be recorded by the coordinates of the display unit or other marking methods, and the details are not described herein.

[0145] The second obtaining unit 302 is configured to obtain the first binary value corresponding to the gray scale of an arbitrary pixel in the current frame image.

[0146] The third obtaining unit 303 is configured to obtain the second binary value corresponding to the gray scale of the pixel in the next frame image.

[0147] In the embodiment, please refer to Figure 1 , which shows the storage schematic diagram of the image data in the prior art, as Figure 1As shown, SDRAM1 and SDRAM2 are respectively used to store image data of the previous frame and the next frame (the image data of the previous frame and the next frame can also be stored in the same SDRAM, and SDRAM1 and SDRAM2 are respectively represented as two storage areas), in which image data of each pixel is respectively stored, for example, data1, data2,..., and dataN. First, the electronic paper needs to be initialized for display after power-on, so that the subsequent image display has a better reference value. For example, after the display is initialized, the data of SDRAM1 is all set to 0, the first frame image data is stored in SDRAM2, SDRAM2 is compared with SDRAM1 when the first frame image is displayed, the lookup table is queried, and the output is displayed, and at the same time, the first frame image data (the previous frame image relative to the image to be displayed for the second frame after the first frame image is displayed, which is also called the previous frame image data at this time) is stored in SDRAM1; the second frame image data (the next frame image data) is stored in SDRAM2, SDRAM2 is compared with SDRAM1 when the second frame image is displayed, the lookup table is queried, and the output is displayed, and SDRAM1 stores the current image; the image data to be displayed for the next frame is stored in SDRAM2, and the like is sequentially repeated, and the display screen to be displayed can be output by cyclic execution.

[0148] In the embodiment, first, the electrophoretic display combined with RGB filter is taken as an example for illustration, and the color particle electrophoretic display application can also be applied to the embodiment. The microcapsule can display black and white colors, and also supports gray scale display mode, such as GC4, GC8 or GC16 mode, wherein GC represents gray scale clear screen refresh, and 4, 8, 16 represent the maximum number of gray scales supported by different modes. Currently, the ink screen can support 16 levels of gray scale display, and taking the GC16 mode as an example, the mode provides 16 levels of gray scale display effect from 0 to 15, 0 corresponds to white, 15 corresponds to black, and 1 to 14 correspond to different gray effects from white to black in turn. Of course, in actual application, there is also a solution to define 0 level as black and 15 level as white, and the embodiment does not limit this. When displaying each level of gray scale between black and white, the black and white ink particles are no longer driven to the top or bottom of the microcapsule, but are moved and suspended at a certain position in the microcapsule to meet the gray scale display requirement of different gray scales.

[0149] In displaying a frame of image, first, the RGB image is processed to gray scale, and the RGB value of each pixel in the image is converted to a 16-level gray scale value, then the look-up table (LUT) is searched by the time sequence controller circuit to obtain the driving waveform of each pixel, which contains the current / voltage, pulse length, pulse period and other information that the pixel needs to use in displaying the current frame. After receiving all the driving waveforms corresponding to the pixels in the current frame, the electronic paper controller drives the microcapsules corresponding to each pixel in the ink screen according to the driving parameters carried by the driving waveform, controls the black and white ink particles in the microcapsules to move from the current position to the next position, so as to refresh the ink screen to display the next frame of image content.

[0150] The LUT table is a driving mapping table of the ink screen obtained and recorded by the ink screen supplier based on the screen hardware test, which records the driving waveform of the pixel corresponding to different display requirements / conditions. The dependent variables in the mapping table usually include: the gray scale value of the pixel in the next frame, the gray scale value of the pixel in the previous frame, and the current screen temperature. The gray scale value of the pixel in the next frame determines the position to which the ink particles should move, and the gray scale value of the pixel in the previous frame corresponds to the current position of the ink particles. The screen temperature needs to be considered because the viscosity of the filling liquid in the microcapsule is different under different temperature conditions. Under the same driving waveform condition, the viscosity of the filling liquid increases, the moving resistance of the ink particles increases, the moving distance of the ink particles is insufficient, which will cause the screen to display too dark or too light, affecting the display effect. Therefore, it is necessary to adjust the driving waveform according to the current screen temperature to ensure that the ink particles can fully move to the specified position under different temperatures, and achieve sufficient and accurate gray scale expression. Usually, the viscosity of the filling liquid is negatively correlated with the temperature, that is, the lower the temperature, the greater the viscosity of the filling liquid.

[0151] In the LUT table, all permutation and combination pairs of the three parameters of "next frame gray scale value", "previous frame gray scale value" and "current screen temperature" are given, and each permutation and combination pair is mapped to a corresponding driving waveform parameter to form the above-mentioned mapping table.

[0152] In the look-up table, the timing controller circuit obtains the gray scale image of the next frame from a system on chip (SOC), and obtains the gray scale value of each pixel from the image; then the timing controller circuit obtains the gray scale image of the previous frame from the cache, and obtains the gray scale value of each pixel from the image; then the timing controller circuit queries the temperature data around the ink screen from the SOC, and the data is monitored by a temperature sensor arranged inside the terminal and close to the back plate of the ink screen and transmitted to the SOC. After obtaining the above data, the timing controller circuit takes the three data as dependent variables to query the corresponding driving waveform in the LUT table, and when the driving waveform corresponding to each pixel in a frame of image is obtained, the look-up table process is completed.

[0153] The first calculation unit 304 calculates the difference between the second binary value and the first binary value of the pixel;

[0154] The establishing unit 305 establishes groups for a predetermined number of adjacent pixels, and each group contains a consistent number of pixels;

[0155] The first distribution unit 306 distributes an in-group number to each pixel in the group;

[0156] The second generation unit 307 generates a second driving waveform lookup table according to the in-group number, the corresponding relationship and the difference.

[0157] The second driving unit 308 drives each display unit according to the second driving waveform lookup table;

[0158] The third driving unit 309 drives the remaining display units of the group according to the second driving waveform lookup table.

[0159] In the embodiment, the establishing unit 305 establishes groups for a predetermined number of adjacent pixels, and each group contains a consistent number of pixels;

[0160] The first distribution unit 306 distributes an in-group number to each pixel in the group;

[0161] The second generation unit 307 generates a second driving waveform lookup table according to the in-group number, the corresponding relationship and the difference.

[0162] Please refer to Figure 6In the embodiment, the matrix unit of M*N is prefix coded with detailed information, and the coding length is log2N bit length, for example, the RGBW ordered color ink screen is coded into a 2*2 size matrix, the R component prefix is b:00, the G component prefix is b:01, the B component prefix is b:02, and the W component prefix is b:03. The group number can be defined as binary, including: the R component prefix is b:00, the G component prefix is b:01, the B component prefix is b:10, and the W component prefix is b:11.

[0163] It should be noted that the purpose of setting the above group number is to correspond the group to the filter, and the color resistance of the pixel corresponds to the filter.

[0164] In the embodiment, the microcapsule filter is not limited, and the color particle microcapsule, microcup, and plasma structure are locally limited, for example, RGB can also be applied to CMYH, that is, cyan, magenta, yellow, and white. For example, the C component prefix is b:00, the M component prefix is b:01, the K component prefix is b:10, and the W component prefix is b:11.

[0165] The second driving unit 310 drives each display unit according to the second driving waveform lookup table;

[0166] The third driving unit 311 drives the remaining display units in the group according to the second driving waveform lookup table.

[0167] For a screen capable of representing n bits, that is, 2n, according to the characteristics of each component of the matrix unit, the corresponding driving pulse sequence (P0, P1, P2, P3,..., Pn) from the old gray scale to the new gray scale is generated.

[0168] The component coding prefix is added in front of each pulse, and the coding is stored as an ink screen driving coding table.

[0169] When the ink screen is refreshed, the image matrix pixel component coding is taken, for example, the RGB color ink screen is coded as b:00-b:11, together with the front and rear picture pixel values, to form the waveform table index corresponding to the ink screen pixel. According to the waveform table index, the driving pulse of the corresponding component is found, and the ink screen is refreshed.

[0170] In the embodiment, in addition to the technical effects in the first embodiment, the four pixels form a group, and when any one of the pixels is driven, the other pixels in the group are also driven. When a group is treated as a color display unit, the influence between adjacent pixels is a problem within the display unit. As each color display unit, the display unit does not affect the display unit. Thus, the problems such as residual image (ghost) and edge diffusion caused by the mutual influence of adjacent pixels are effectively solved.

[0171] On a 32-bit machine, 4 pixels (a group) are processed each time, which is more than 5 times faster than the prior art in which one pixel is processed each time.

[0172] The device embodiment further comprises:

[0173] The second distribution unit is configured to assign a group number to each group;

[0174] The storage unit is configured to store all groups according to the group numbers.

[0175] It should be noted that the processor can traverse to the group number of the corresponding pixel according to the group number of the display unit, and then determine the group number. The second distribution unit assigns a group number to each group, and stores all groups in the storage unit according to the group number.

[0176] The data processing method is optimized, so that the data processing process is greatly simplified to improve the data processing efficiency, the data storage form of the waveform is changed to reduce the required storage space of the flash memory, and the cost is reduced

[0177] In the embodiments provided in the present application, it should be understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, code, or any appropriate combination thereof. For hardware implementation, the processor can be implemented in one or more of the following units: application specific integrated circuit (ASIC), digital signal processor (DSP), digital signal processing device (DSPD), programmable logic device (PLD), field programmable gate array (FPGA), processor, controller, microcontroller, microprocessor, other electronic units designed to implement the functions described herein, or a combination thereof. For software implementation, part or all of the processes of the embodiments can be instructed by a computer program to relevant hardware. When implemented, the above program can be stored in a computer readable storage medium or transmitted as one or more instructions or codes on a computer readable storage medium. The computer readable storage medium includes computer storage medium and communication medium, wherein the communication medium includes any medium that facilitates the transmission of a computer program from one place to another. The storage medium can be any available medium that can be accessed by a computer. The computer readable storage medium can include but is not limited to RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer.

[0178] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, modifications or equivalent replacements of the technical solutions described in the foregoing embodiments can still be made by those skilled in the art, or some technical features can be replaced by equivalent features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electrophoretic display driving method, characterized by, The method comprises: obtaining the correspondence between each pixel and its display unit in the display device; obtaining a first binary value corresponding to the gray scale of any pixel in the current frame image; obtaining a second binary value corresponding to the gray scale of the pixel in the next frame image; establishing groups for a predetermined number of adjacent pixels, each group containing a consistent number of pixels; assigning an intra-group number to each pixel in the group; generating a first driving waveform lookup table according to the intra-group number, the first binary value, the second binary value, and the correspondence; driving each display unit according to the first driving waveform lookup table; driving the remaining display units in the group according to the first driving waveform lookup table.

2. The electrophoretic display driving method according to claim 1, wherein The method further comprises, after establishing groups for a predetermined number of adjacent pixels and assigning group numbers: assigning a group number to each group; storing all groups according to the group number.

3. The electrophoretic display driving method according to claim 1 or 2, characterized by, The method further comprises, after obtaining a first binary value corresponding to the gray scale of any pixel in the current frame image and obtaining a second binary value corresponding to the gray scale of the pixel in the next frame image: calculating the difference between the second binary value and the first binary value of the pixel; generating a second driving waveform lookup table according to the intra-group number, the difference, and the correspondence.

4. The electrophoretic display driving method according to claim 3, wherein The method comprises: The second driving waveform lookup table comprises a driving waveform corresponding to the difference; The number of non-zero main pulses in the driving waveform is related to the difference, and the direction corresponds to the sign of the difference.

5. The electrophoretic display driving method according to claim 4, wherein The method comprises: The main pulse comprises a pulse for driving to a target gray scale error of plus or minus 10 brightness units.

6. The electrophoretic display driving method according to claim 3, wherein The method comprises: obtaining temperature information; generating a third driving waveform lookup table according to the temperature information, the intra-group number, the difference, and the correspondence.

7. The electrophoretic display driving method according to claim 3, wherein The method comprises: calculating a pulse direction value according to the second binary value and the first binary value; generating a third driving waveform lookup table according to the pulse direction value, the intra-group number, the difference, and the correspondence.

8. An electrophoretic display driving device, characterized by comprising: The device comprises: a first obtaining unit configured to obtain the correspondence between each pixel and its display unit in the display device; a second obtaining unit configured to obtain a first binary value corresponding to the gray scale of any pixel in the current frame image; a third obtaining unit configured to obtain a second binary value corresponding to the gray scale of the pixel in the next frame image; an establishing unit configured to establish groups for a predetermined number of adjacent pixels, each group containing a consistent number of pixels; a first assigning unit configured to assign an intra-group number to each pixel in the group; a first generating unit configured to generate a first driving waveform lookup table according to the intra-group number, the first binary value, the second binary value, and the correspondence; a first driving unit configured to drive each display unit according to the first driving waveform lookup table; a second driving unit configured to drive the remaining display units in the group according to the first driving waveform lookup table.

9. The electrophoretic display driving apparatus according to claim 8, wherein The device comprises: a second assigning unit configured to assign a group number to each group; a storage unit configured to store all groups according to the group number.

10. The electrophoretic display driving apparatus according to claim 8, wherein The device comprises: A first calculation unit is configured to calculate a difference between the second binary value and the first binary value of the pixel; A second generation unit is configured to generate a second driving waveform lookup table according to the group number, the difference and the correspondence.

11. The electrophoretic display driving apparatus according to claim 8, wherein The device comprises: A fourth acquisition unit is configured to acquire temperature information: A third generation unit is configured to generate a third driving waveform lookup table according to the temperature information, the group number, the difference and the correspondence.

12. The electrophoretic display driving apparatus according to claim 8, wherein The device comprises: A second calculation unit is configured to calculate a pulse direction value according to the second binary value and the first binary value of the pixel; A fourth generation unit is configured to generate a third driving waveform lookup table according to the pulse direction value, the group number, the difference and the correspondence.

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