Method for displaying multi-colors by driving four-color film material with three-color chip of electronic paper

Abstract

The application provides a method for displaying multiple colors by driving a four-color film material by an electronic paper three-color chip, the method comprises the following steps: converting a color image to be displayed into a 256 gray scale image and mapping the 256 gray scale image to 16 gray scales; analyzing 0-F hexadecimal data obtained by taking modulus of the 16 gray scales through an image data algorithm to determine a display change area, and merging pixels with the same driving scheme by using a grouping compression algorithm; constructing a gray scale-driving scheme mapping table, and distributing gray scale data to corresponding registers of the three-color chip; performing multi-round layered refreshing; and realizing pure display of 5-16 colors through multi-round refreshing superposition, and only refreshing the change area. The application realizes differential driving of different color particles by the same voltage driving logic through multiple driving schemes and particle channels, and realizes pure display of 5-16 colors through 5-round layered superposition, the color transition is smooth, and there is no mottling at a close distance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic paper display, in particular to a method for displaying multi-colors by electronic paper three-color chip driving four-color film material. BACKGROUND

[0002] Electronic paper has been widely used in electronic price tags, electronic reading, smart wear and other fields due to its unique advantages of low power consumption, paper-like visual effect, flexible display and the like. Among them, the four-color ink screen, which can display four basic pure colors of black, white, red and yellow, has become one of the mainstream products in the market, but it has significant limitations in multi-color display demand.

[0003] When the existing four-color ink screen displays multi-color images, it generally relies on dithering algorithm to simulate target colors by mixing and matching four pure pixel points of black, white, red and yellow. This method has many defects: the mottling phenomenon is prominent when observed at close range, and the picture is rough; color presentation relies on pixel mixing and matching, and cannot achieve pure transition colors, resulting in deviation from the real target color; and the color customization is poor, making it difficult to meet the color demand of diversified scenarios. At the same time, in the electronic paper display module, the 1bit data IC cannot directly realize high-quality multi-gray scale and multi-color display due to hardware limitations. In the existing technology, although there is a scheme for realizing sixteen gray scales by multiple refreshing and superimposition, this scheme only focuses on gray scale improvement and does not solve the demand for multi-color display, and its refreshing strategy and waveform control logic are not suitable for multi-color display, which cannot be directly applied to multi-color expansion display of four-color film material.

[0004] Therefore, there is an urgent need for a method for displaying multi-colors by electronic paper three-color chip driving four-color film material. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a method for displaying multi-colors by electronic paper three-color chip driving four-color film material, which realizes 5-16 pure color display and reduces the mottling phenomenon by optimizing gray scale mapping, driving scheme allocation and multi-round refreshing and superimposition strategy.

[0006] The technical scheme of the present application is as follows: a method for displaying multi-colors by electronic paper three-color chip driving four-color film material, comprising the following steps:

[0007] S1), converting a color image to be displayed into a 256 gray scale image, and mapping it to 16 gray scales by a uniform quantization algorithm; each target color corresponds to a unique 16 gray scale value, and the gray scale values of each target color do not overlap;

[0008] S2), configuring the 1bit data IC to compare new and old data patterns, analyzing the 0-F hexadecimal data after 16 gray scale modulo by image data algorithm, determining the display change area, and merging the pixels of the same driving scheme by grouping compression algorithm;

[0009] S3), constructing a gray scale-driving scheme mapping table, and distributing the gray scale data to the corresponding registers of the three-color chips through a k-means clustering algorithm;

[0010] S4), performing multiple rounds of hierarchical refreshing, controlling 2-4 gray scale data in each round of refreshing, calling the corresponding driving scheme to drive the motion of the four-color film particles, and adjusting the basic color depth; after each refreshing, the pixel state is obtained to dynamically adjust the waveform parameters of the next round;

[0011] S5), realizing pure display of 5-16 colors through multiple rounds of refreshing superposition, and only refreshing the changed area.

[0012] As preferred, in step S1), the target colors include black, dark red, red, dark yellow, gray 2, orange, yellow, pink, gray 1, and white; and the corresponding 16 gray scale values are 0, 3, 5, 6, 8, 9, 10, 11, 12, and 15, respectively.

[0013] As preferred, in step S1), the 1-bit data IC is configured to compare new and old data modes, and the specific configuration is as follows:

[0014] S211), register configuration is performed on the 1-bit data IC, and mode control instructions are written to switch it to the new and old data comparison mode. In this mode, the IC built-in cache unit stores the last frame of display data and receives the 0-F hexadecimal data after 16 gray scale modulo in real time;

[0015] S212), when the pixel gray scale change difference is greater than or equal to the gray scale threshold, it is determined as a changed pixel, and when the difference is less than the gray scale threshold, it is determined as an unchanged pixel;

[0016] S213), the change area marking function of the IC is enabled, and the new and old data are compared pixel by pixel through the hardware logic circuit to generate a change area mask Mask.

[0017] As preferred, in step S1), the 0-F hexadecimal data after 16 gray scale modulo is analyzed through an image data algorithm to determine the display change area, and the specific configuration is as follows:

[0018] S221), a row-column scanning algorithm is used to traverse the hexadecimal data matrix after 16 gray scale modulo, extract the gray scale value of each pixel, and construct a current frame gray scale data matrix;

[0019] S222), a neighborhood connectivity analysis algorithm is used to filter isolated single-point changed pixels, and the final change area data matrix is obtained after filtering.

[0020] As preferred, in step S1), a grouping compression algorithm is used to merge pixels with the same waveform data, and the specific configuration is as follows:

[0021] S231), traversing the final change region data matrix based on the preset gray scale-driving scheme mapping table, matching the corresponding preliminary driving scheme for the gray scale value of each change pixel to generate a temporary driving matrix;

[0022] S232), grouping the temporary driving matrix using a region growing clustering algorithm to construct a compressed data frame and realize data compression;

[0023] S233), generating a compressed data frame for each group, and the data frame format is defined as: {group identifier, region coordinates, waveform type, voltage parameter, check bit};

[0024] S234), statistics the data amount before and after compression, and calculates the compression ratio.

[0025] As preferred, in step SS232), the region growing clustering algorithm is used to group the temporary driving matrix to construct a compressed data frame and realize data compression, and the specific process is as follows:

[0026] S2321), initializing a seed pixel queue, starting from the top left corner of the temporary driving matrix, selecting the first unmarked pixel as the seed pixel, and recording its driving scheme;

[0027] S2322), taking the seed pixel as the center, traversing its neighborhood pixels, judging whether the driving schemes of the neighborhood pixels are consistent and whether they are change pixels, if so, including them in the current group and marking them as processed;

[0028] S2323), repeating step S2322) until there is no new pixel in the current group, and outputting the region coordinates of the current group and the corresponding driving scheme;

[0029] S2324), continue scanning the matrix, select the next unmarked pixel as a new seed pixel, repeat steps S2322)-S2323) until all change pixels are grouped.

[0030] As preferred, in step S3), the gray scale-driving scheme mapping table includes gray scale value, target color, color system, corresponding particle, driving scheme type, voltage parameter, particle channel, refresh round, and register number.

[0031] As preferred, in step S3), the four-color film material is built-in black, white, red and yellow four kinds of charged particles, and the particle movement is controlled by voltage direction and time length: positive voltage drives the target particle to migrate to the display surface, and negative voltage drives the target particle to migrate to the inside of the film material, and the voltage time length determines the number of particle migration, and then different color depth or mixed color is presented.

[0032] Preferably, in step S3, the driving scheme type includes four basic driving schemes and a plurality of mixed driving schemes, wherein the basic driving scheme drives a single particle to move, and the mixed driving scheme drives a plurality of particles to move.

[0033] The basic driving scheme includes no change, forward driving, reverse driving, and keeping locked.

[0034] The mixed driving scheme includes driving combinations corresponding to deep red, pink, deep yellow, orange, gray 1, and gray 2, and the mixed driving of different particles is realized by combination of the basic driving scheme and optimization of the voltage parameter.

[0035] Preferably, in step S3, the gray scale data is assigned to the corresponding register of the three-color chip by using a k-means clustering algorithm, and the step specifically includes the following steps.

[0036] S31), extracting all non-zero gray scale values from the final change area data matrix, constructing a sample data set, and defining a feature vector of each sample;

[0037] S32), combining the number of registers of the three-color chip, the color system, and the distribution of refresh rounds, and setting the number of clusters .

[0038] S33), determining the initial clustering center by using the elbow rule, and selecting samples with the largest difference in feature vectors as the initial center;

[0039] S34), calculating the Euclidean distance of each sample from each clustering center; assigning each sample to the cluster corresponding to the clustering center with the nearest Euclidean distance, and updating the clustering center by taking the mean value of the feature vectors of all samples in the cluster;

[0040] Repeating the steps of Euclidean distance calculation, sample assignment, and center updating until the change amount of the clustering center meets the convergence condition, and stopping iteration;

[0041] S35), assigning the converged cluster to the main register of the three-color chip according to the priority of the color system, the particle channel, and the refresh round, and using the standby register to buffer temporary data and feedback adjustment parameters during the refresh process.

[0042] Preferably, in step S4, based on the register allocation result and the driving control of the 1-bit data IC, a 5-round layered refresh process is designed, each round of refresh calls the driving scheme stored in the corresponding register, realizes color display by driving particle motion through voltage, and collects pixel state through the feedback module after refresh to dynamically adjust the waveform parameters of the next round.

[0043] As preferred, in step S4), the same forward driving voltage can bind any one of white, red, yellow and black particle channels, the binding relationship is switched through register instruction, the differential driving of the same voltage driving logic to different color particles is realized, the first round forward driving binds the white channel to drive white particles, and the second round forward driving binds the red channel to drive red particles.

[0044] As preferred, in step S4), the actual gray scale value and actual optical brightness of the pixel are collected through the feedback module after each round of refreshing, and the deviation value is calculated by comparing with the target value, if the deviation value exceeds the preset threshold, the voltage duration of the corresponding driving scheme of the next round is adjusted according to the rule.

[0045] The beneficial effects of the present application are:

[0046] 1. The present application realizes the differential driving of the same voltage driving logic to different color particles through multiple driving schemes and particle channels, realizes 5-16 kinds of pure color display through 5 rounds of layered superposition, the color transition is smooth, there is no mottling at close distance, and the total refreshing time is controlled within 27-30 seconds.

[0047] 2. The present application dynamically collects state data through the feedback module after each round of refreshing, adjusts the driving scheme parameters based on the deviation ratio, the color drift is less than or equal to 0.2 gray scale, and the brightness deviation is less than or equal to 8 cd / m².

[0048] 3. The present application can add new colors by updating the driving scheme and particle channel combination and clustering parameters in the gray scale-driving scheme mapping table; the reserved register and extended clustering cluster can adapt to the future higher color demand scene. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The flowchart of the method of the present application is shown in the figure;

[0050] Figure 2 The flowchart of the image data algorithm of the present application is shown in the figure;

[0051] Figure 3 The flowchart of the grouping compression algorithm of the present application is shown in the figure;

[0052] Figure 4 The flowchart of the k-means clustering algorithm of the present application is shown in the figure;

[0053] Figure 5 The comparison chart of the multi-color display effect of the present application and the prior art is shown in the figure. DETAILED DESCRIPTION

[0054] The specific embodiments of the present application will be further described below in combination with the drawings:

[0055] As Figure 1As shown, the embodiment provides a method for displaying multiple colors by an electronic paper three-color chip driving a four-color film material, comprising the following steps:

[0056] S1), converting the color image to be displayed into a 256 gray scale image, and mapping the 256 gray scale image to 16 gray scales by a uniform quantization algorithm; each target color corresponds to a unique 16 gray scale value, and the gray scale values of each target color do not overlap;

[0057] In this embodiment, the uniform quantization algorithm is represented as:

[0058] ,

[0059] In the formula, represents the 16 gray scale value after quantization; is a gray scale value of 0-256; represents the floor function;

[0060] Select the target display color, ensure that the RGB parameters corresponding to each target color are converted to 16 gray scales, and the gray scale values are significantly different and do not overlap, to avoid color confusion.

[0061] For example, the embodiment gives the target color and parameters as shown in Table 1;

[0062] Table 1 Target color and parameters

[0063]

[0064] S2), configure the 1bit data IC to compare new and old data modes, analyze the 0-F hexadecimal data after 16 gray scale modulo by image data algorithm, determine the display change area, and merge the same waveform data pixels by grouping compression algorithm;

[0065] In this embodiment, the 1bit data IC is configured to compare new and old data modes, as follows:

[0066] S211), register configuration is performed on the 1bit data IC, and mode control instructions are written to switch it to the new and old data comparison mode. In this mode, the IC built-in cache unit will store the last frame display data and receive the 0-F hexadecimal data after 16 gray scale modulo in real time;

[0067] S212), and the embodiment sets the pixel gray scale change difference value ≥1 as the change pixel, and the difference value <1 as the unchanged pixel, to avoid invalid refresh caused by small gray scale fluctuations;

[0068] S213), enable IC change area marking function, compare new and old data pixel by pixel through hardware logic circuit, generate change area mask Mask, 1 in mask represents change pixel, 0 represents unchanged pixel, mask data corresponds to display pixel array one by one.

[0069] In the embodiment, as shown in the figure, 0-F hexadecimal data after 16 gray scale modulo is analyzed by image data algorithm, and the display change area is determined, and the specific process is as follows: Figure 2

[0070] S221), 16 gray scale modulo hexadecimal data matrix is traversed by using row-column scanning algorithm, and the gray scale value of each pixel is extracted to construct the current frame gray scale data matrix , wherein, is the row and column number of the hexadecimal data matrix;

[0071] S222), filter isolated single-point change pixels by using neighborhood connectivity analysis algorithm, wherein the single-point change pixel is a pixel with a connected domain area of less than 3 pixels; after filtering, the final change area data matrix is obtained.

[0072] In the embodiment, as shown in the figure, the pixels of the same waveform data are merged by using grouping compression algorithm, and the specific process is as follows: Figure 3

[0073] S231), based on the preset gray scale-driving scheme mapping table, traverse the final change area data matrix , match the corresponding preliminary driving scheme for each change pixel gray scale value to generate a temporary driving matrix .

[0074] S232), group the temporary driving matrix by using region growing clustering algorithm, construct a compressed data frame, realize data compression, and the specific process is as follows:

[0075] S2321), initialize the seed pixel queue, scan from the top left corner of the temporary driving matrix , select the first unmarked pixel as the seed pixel, and record its driving scheme .

[0076] S2322), traverse the 8-neighborhood pixels of the seed pixel, judge whether the driving scheme of the neighborhood pixel is consistent with and whether it is a change pixel, if yes, it is included in the current group, and is marked as processed;

[0077] ​​S2323), repeating step S2322) until there is no new pixel in the current group, and outputting the region coordinates of the current group and the corresponding driving scheme ;

[0078] S2324), continuing to scan the matrix, selecting the next unmarked pixel as a new seed pixel, repeating steps S2322) and S2323) until all the changed pixels are grouped.

[0079] S233), generating a compressed data frame for each group, and defining the data frame format as {group identification, region coordinates, waveform type, voltage parameter, and check bit}.

[0080] S234), counting the data amount before and after compression, and calculating the compression ratio :

[0081] ,

[0082] wherein, , The data amount before and after compression; ensure that the compression ratio is ≥ 30%, meeting the data transmission requirements of high-resolution modules.

[0083] S3), constructing a gray scale-driving scheme mapping table, and distributing the gray scale data to the corresponding registers of the three-color chip through a k-means clustering algorithm;

[0084] In this embodiment, the four-color film material is built-in with black, white, red, and yellow charged particles, and the particle movement is controlled by the voltage direction and time length: a forward voltage drives the target particles to migrate to the display surface, a reverse voltage drives the target particles to migrate to the inside of the film material, and the voltage time length determines the number of particle migration, thereby presenting different color depths or mixed colors.

[0085] Four basic driving schemes and multiple mixed driving schemes are set, wherein the basic driving scheme drives the movement of a single particle, and the mixed driving scheme drives the movement of multiple particles.

[0086] In this embodiment, by clustering the 16 gray scale data according to color system and refresh round and distributing them to the two independent registers of the three-color chip, efficient use of register resources is achieved, and data conflicts are avoided, as shown in Figure 4 specifically comprising the following steps:

[0087] S31), extracting all non-zero gray scale values from the final changed region data matrix , and constructing a sample data set ;

[0088] ,

[0089] wherein, Total number of changed pixels

[0090] Feature vector of each sample is defined as: ,

[0091] In the formula, is the gray scale value of the pixel; is the color category code; is the particle channel code; is the refresh round code;

[0092] S32), combined with the number of registers of the three-color chip and the distribution of color categories and refresh rounds, set the number of clusters (reserve 2 registers as backup cache), ensure that the data streams corresponding to each cluster do not conflict with each other, and can be processed in parallel in the same refresh round;

[0093] S33), determine the initial cluster center by elbow rule, select the sample with the largest difference in feature vector as the initial center ; ;

[0094] (black system, black and white channels, first round);

[0095] (red system, red and white channels, second round);

[0096] (red system, red and black channels, third round);

[0097] (yellow system, yellow and black channels, fourth round);

[0098] (yellow system, red and yellow channels, third round);

[0099] (white system, white channel, first round);

[0100] S34), calculate the Euclidean distance between each sample and each cluster center , that is:

[0101] ,

[0102] In the formula, is the gray scale value of the first pixel; is the color category code of the first pixel; is the color category code of the first pixel; is the color category code of the first pixel; is the color category code of the first pixel; ​Refresh round encoding of the pixel; Particle channel encoding of the pixel; Particle channel encoding of the pixel;

[0103] Then each sample is assigned to the cluster corresponding to the nearest cluster center The feature vectors of all samples in the cluster are averaged, and the cluster center is updated ;

[0104] The above distance calculation, sample assignment and center update steps are repeated until the change of the cluster center is ≤0.1, and the iteration is stopped.

[0105] S35), the six converged cluster clusters are assigned to the two main registers of the three-color chip according to the color system, particle channel and priority of refresh round, and the standby register is used to buffer temporary data and feedback adjustment parameters during the refresh process.

[0106] S4), multi-round hierarchical refresh is performed, and 2-4 gray scale data are controlled in each round of refresh, the basic driving scheme or the mixed driving scheme in the corresponding register is called to drive the particle motion of the four-color film material, and the basic color depth is adjusted; after each refresh, the pixel state is dynamically adjusted to adjust the waveform parameters of the next round;

[0107] In this embodiment, based on the register allocation result and the driving control of the 1bit data IC, a 5-round hierarchical refresh process is designed, each round of refresh calls the driving scheme stored in the corresponding register, realizes color display through voltage driving particle motion, collects the pixel state through the feedback module after refresh, and dynamically adjusts the waveform parameters of the next round to form a closed loop control, and the specific steps are as follows:

[0108] In this embodiment, the sampling frequency of the feedback module is 100Hz, the sampling accuracy is 12 bits, and the sampling area covers all the effective pixels of the display module.

[0109] The pixel state evaluation index is set: including the actual gray scale value , the actual optical brightness ;

[0110] The deviation between the preset actual gray scale value and the target gray scale value is ≤0.2, and the deviation between the actual optical brightness and the target brightness is ≤8cd / m²;

[0111] The parameter adjustment rule is defined: if the deviation exceeds the threshold, the voltage duration of the corresponding waveform of the next round is dynamically adjusted according to the deviation proportion × adjustment step, the adjustment step is 0.5ms, and the voltage amplitude is fixed at ±15V or a preset value, so as to avoid the instability of particle motion caused by amplitude adjustment.

[0112] 1st round refresh: black, red, yellow pure color basic display

[0113] The driving chip sends a data read instruction to the main register, extracts the compressed driving scheme and voltage parameters, and activates the corresponding particle channel at the same time.

[0114] 1bit data IC calls to execute basic driving and hybrid driving, and drives four-color film particle motion according to the preset voltage parameters, as follows:

[0115] Black display: drive the black particles in the black channel by forward voltage to completely migrate to the display surface, showing pure black.

[0116] Red display: drive the red particles in the red channel by forward voltage to completely migrate to the display surface, showing pure red.

[0117] Yellow display: drive the yellow particles in the yellow channel by forward voltage to completely migrate to the display surface, showing pure yellow.

[0118] After the refresh is completed, the feedback module collects data for each sampling point, records the actual gray scale value , actual optical brightness , calculates the deviation value, and if the deviation does not exceed the threshold value, there is no need to adjust the parameters, and if the deviation exceeds the threshold value, the next round is adjusted according to the rules, and the actual state data of this round refresh is stored in the standby register.

[0119] 2nd round refresh: red and yellow color display

[0120] The driving chip reads the driving scheme of the main register, and the standby register retrieves the reference state data of the 1st round refresh at the same time.

[0121] Execute basic driving and hybrid driving scheme:

[0122] Deep red display: drive the black particles in the red channel by forward voltage to completely migrate to the display surface, showing deep red.

[0123] Pink display: through the hybrid driving scheme, first drive a small amount of red particles in the red channel to migrate by forward voltage, and then drive a large amount of white particles in the white channel to migrate by forward voltage, the two particles are mixed on the display surface to form pink.

[0124] Collect the actual gray scale value , actual optical brightness of deep red and pink through the feedback module, and calculate the deviation value, if the deviation does not exceed the threshold value, there is no need to adjust the parameters, and if the deviation exceeds the threshold value, the next round is adjusted according to the rules, and the actual state data of this round refresh of deep red and pink is updated to the standby register.

[0125] Round 3 refresh: red and yellow color display;

[0126] The driving chip reads the driving scheme in the main register, calls the reference state data of the yellow system in the standby register, and reads the adjustment parameters in the standby register;

[0127] Deep yellow display: through mixed driving, first drive the red particles in the red channel to completely migrate with positive voltage, then drive a small amount of black particles in the black channel to approach the red particles with reverse voltage, and the two particles are mixed to form deep red.

[0128] Orange display: through mixed driving, drive the red particles in the red channel to partially migrate with positive voltage, and drive the yellow particles in the yellow channel to partially migrate with positive voltage, and the two particles are mixed in proportion to the voltage to present orange.

[0129] The actual gray scale values of deep yellow and orange are collected by the feedback module , actual optical brightness The deviation value is calculated, if it does not exceed the threshold value, the adjustment parameter is not needed, if the deviation exceeds the threshold value, the next round is adjusted according to the rules, and the actual state data of deep red and orange refreshed in this round is updated to the standby register.

[0130] Round 4 refresh: gray and white color display;

[0131] The driving chip reads the driving scheme in the main register, calls the reference state data adjustment parameters of the standby register.

[0132] Gray 1 display: through mixed driving, first drive a large number of black particles in the black channel to migrate with positive voltage, then drive a small amount of white particles in the white channel to migrate with negative voltage, and the two particles are mixed on the display surface to present dark gray.

[0133] The actual gray scale values of yellow and deep yellow are collected by the feedback module , actual optical brightness The deviation value is calculated, if it does not exceed the threshold value, the adjustment parameter is not needed, if the deviation exceeds the threshold value, the next round is adjusted according to the rules, and the actual state data of yellow and deep yellow refreshed in this round is updated to the standby register.

[0134] Round 5 refresh: gray and white color display;

[0135] The driving chip reads the driving scheme in the main register, calls the reference state data adjustment parameters of the standby register.

[0136] Gray 2 display: through mixed driving, first drive a large number of black particles in the black channel to migrate with positive voltage, then drive a small amount of white particles in the white channel to migrate with negative voltage, and the two particles are mixed on the display surface to present light gray.

[0137] White display: drive the white particles in the white channel by forward voltage to completely migrate to the display surface, showing pure white.

[0138] Collect the actual gray scale values of gray 2 and white by the feedback module , actual optical brightness and calculate the deviation value. If the deviation does not exceed the threshold value, there is no need to adjust the parameters. If the deviation exceeds the threshold value, adjust the next round according to the rules, and update the actual state data of yellow and deep yellow refreshed in this round to the standby register.

[0139] Solidify the waveform parameters optimized in this round to the gray scale-driving scheme mapping table.

[0140] S5), realize pure display of 5-16 colors through multiple rounds of refreshing superposition, and only refresh the changed area.

[0141] As Figure 5 is the multi-color display effect comparison chart of the present embodiment and the prior art, wherein Figure 5 (a) of the present embodiment is the color development effect chart; Figure 5 (b) of the prior art is the color development effect. From Figure 5 it can be seen that Figure 5 all target colors (red, yellow, orange, pink, black, white, light and dark gray) in (a) are presented in pure quality, without any speckle or particle feeling, for example, the 50% off red identification color is uniform and full, the orange color transition of Orange is natural, without color deviation or color fracture phenomenon.

[0142] Figure 5 In (b), obvious black and white red and yellow pixel mixed traces can be seen, and the density of speckles is ≥30 points / mm² when observed closely. For example, the edge of the red discount mark is full of black and white speckles, and the orange product name presents a blurred feeling due to pixel mixing, with extremely poor color purity.

[0143] The above embodiments and descriptions described in the specification are only to illustrate the principles and best embodiments of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A method for displaying multiple colors by driving a four-color film material with an electronic paper three-color chip, characterized in that, It comprises the following steps: S1), converting the color image to be displayed into a 256 gray scale image, and mapping to 16 gray scales through a uniform quantization algorithm Each target color corresponds to a unique 16 gray scale value, and the gray scale values of each target color do not overlap; S2), configuring 1bit data IC to compare new and old data patterns, analyzing 0-F hexadecimal data after 16 gray scale modulo through image data algorithm to determine the display change area, and merging pixels with the same driving scheme using a grouping compression algorithm; S3), constructing a gray scale-driving scheme mapping table, and distributing gray scale data to the corresponding registers of the three-color chip through a k-means clustering algorithm; specifically comprising the following steps: S31), extracting all non-zero gray scale values from the final change area data matrix, constructing a sample data set, and defining the feature vector of each sample; S32, set the cluster number according to the number of registers and color coefficients of the three-color chip, and the distribution of refresh rounds ; S33) The elbow rule is used to determine the initial cluster centers, selecting those with the largest differences in feature vectors. One sample was used as the initial center; S34), calculating the Euclidean distance of each sample from each cluster center; assign each sample to the cluster corresponding to the cluster center with the closest Euclidean distance, and take the mean of the feature vectors of all samples in the cluster to update the cluster center; Repeat the steps of Euclidean distance calculation, sample assignment and center update until the change of the cluster center meets the convergence condition, and stop iteration; S35), assign the converged cluster to the main registers of the three-color chip according to the color system, particle channel and priority of refresh round, and use the standby register to cache temporary data and feedback adjustment parameters during the refresh process; S4), based on the register allocation result and the driving control of 1bit data IC, design a 5-round layered refresh process, and control 2-4 gray scale data in each round of refresh; each round of refresh calls the driving scheme stored in the corresponding register, and realizes color display through voltage driving four-color film particle movement to adjust the depth of the base color; Collect pixel state through the feedback module after each refresh, and dynamically adjust the waveform parameters of the next round; S5), realize the pure display of 5-16 colors through multiple rounds of refresh superposition, and only refresh the change area.

2. The method for displaying multiple colors using a three-color chip driving a four-color film material in electronic paper according to claim 1, characterized in that: In step S1, the target colors include black, dark red, red, dark yellow, gray 2, orange, yellow, pink, gray 1, and white; the corresponding 16 gray scale values are 0, 3, 5, 6, 8, 9, 10, 11, 12, and 15, respectively.

3. The method for displaying multiple colors using a three-color chip driving a four-color film material in electronic paper according to claim 1, characterized in that: In step S2, the 0-F hexadecimal data after 16 gray scale modulo is analyzed through the image data algorithm to determine the display change area, specifically as follows: S221), traverse the hexadecimal data matrix after 16 gray scale modulo using a row-column scanning algorithm, extract the gray scale value of each pixel, and construct a current frame gray scale data matrix; S222), filter isolated single-point change pixels using a neighborhood connectivity analysis algorithm, and obtain a final change area data matrix after filtering.

4. The method of claim 3, wherein the method is a method of driving a multi-color display of an electronic paper three-color chip four-color film material, characterized in that: In step S2, the pixels with the same waveform data are merged using a grouping compression algorithm, specifically as follows: S231), based on the preset gray scale-driving scheme mapping table, traverse the final change area data matrix, and match the corresponding preliminary driving scheme for each change pixel gray scale value to generate a temporary driving matrix; S232), group the temporary driving matrix using a region growing clustering algorithm to construct a compressed data frame and realize data compression; S233))generating a compressed data frame for each group; S234))counting the data amount before and after compression, and calculating the compression ratio.

5. The method for displaying multiple colors using a three-color chip driving a four-color film material in electronic paper according to claim 4, characterized in that: In step S232, the temporary driving matrix is grouped by using a region growing clustering algorithm to construct a compressed data frame, and data compression is realized. The specific process is as follows: S2321))initializing a seed pixel queue, starting scanning from the top left corner of the temporary driving matrix, selecting the first unmarked pixel as the seed pixel, and recording its driving scheme; S2322))taking the seed pixel as the center, traversing the neighborhood pixels, judging whether the driving scheme of the neighborhood pixels is consistent and whether they are changeable pixels, if so, including them in the current group and marking them as processed; S2323))repeating step S2322)until there is no new pixel in the current group, and outputting the region coordinates and corresponding driving scheme of the current group; S2324))continuing to scan the matrix, selecting the next unmarked pixel as a new seed pixel, and repeating steps S2322)-S2323)until all changeable pixels are grouped.

6. The method for displaying multiple colors using a three-color chip driving a four-color film material in electronic paper according to claim 1, characterized in that: In step S3, the four-color film material is built-in with four kinds of charged particles, black, white, red and yellow, and the particle movement is controlled by voltage direction and time length: positive voltage drives the target particles to migrate to the display surface, and reverse voltage drives the target particles to migrate to the inside of the film material, and the voltage time length determines the number of particle migration, and then different color depth or mixed color is presented.

7. The method of claim 6, wherein the method comprises: In step S3, it includes four basic driving schemes and a plurality of mixed driving schemes, wherein the basic driving scheme drives a single particle to move, and the mixed driving scheme drives a plurality of particles to move; The basic driving scheme includes no change, positive driving, reverse driving and keeping locked; The mixed driving scheme includes deep red, pink, deep yellow, orange, gray 1 and gray 2 corresponding driving combinations, which realizes the mixed driving of different particles by combining the basic driving scheme and optimizing the voltage parameters.

8. The method for displaying multiple colors using a three-color chip driving a four-color film material in electronic paper according to claim 7, characterized in that: In step S4, the same positive driving voltage binds any one of white, red, yellow and black particle channels, and the binding relationship is switched by register instruction to realize the differential driving of different color particles by the same voltage driving logic. The first round of positive driving binds the white channel to drive the white particles, and the second round of positive driving binds the red channel to drive the red particles. After each round of refreshing, the actual gray scale value and actual optical brightness of the pixels are collected by the feedback module, and the deviation value is calculated by comparing with the target value. If the deviation value exceeds the preset threshold, the voltage time length of the corresponding driving scheme in the next round is adjusted according to the rules.

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