Color electrophoretic display and method of displaying thereof

Abstract

A color electrophoretic display and a display method thereof, the color electrophoretic display comprising non-color particles and a plurality of color particles. The display method comprises enabling a pen-writing mode, providing a designated pen-writing color, sensing movement of a stylus to output a black pen-writing trace, wherein the color of the black pen-writing trace is presented by the non-color particles and the color particles being close to a top electrode, the color of the black pen-writing trace has a color update time less than 50 milliseconds, and sensing a stop of the stylus to convert the black pen-writing trace into a color pen-writing trace having the designated pen-writing color, wherein the designated pen-writing color has at least one of a change in lightness and a change in at least one of hue and chroma from the color of the black pen-writing trace. The display method of the present disclosure performs a color development step after displaying the pen-writing trace. The color development step using the technique of color blending solves the color development delay problem in a multi-color particle system. The color with the shortest update time is used to present the pen-writing trace in the pen-writing stage, so that the user does not feel the delay.

Description

[0001] This application is a divisional application of the patent application filed on November 1, 2023, with application number 202311441227.5 and entitled "Color Electrophoretic Display and Display Method Thereof". Technical Field

[0002] This disclosure relates to a display method for a color electrophoretic display. Background Technology

[0003] Electrophoretic displays change color by altering the position of charged colored particles relative to the viewing surface; they are commonly referred to as electronic paper (E-Paper). Electrophoretic displays are widely used in e-readers and billboards.

[0004] Recently, color electrophoretic displays have become available in a variety of colors. Their applications have also extended to color e-notes with pen-writing capabilities. However, color electrophoretic displays require precise control over the position of each color particle. When the electrophoretic medium contains multiple particles, the time required to adjust particle positions is significantly longer than that required for monochrome displays. Because color electrophoretic displays have more and more complex internal particles (compared to monochrome displays), the factors influencing particle movement are more complex, such as electric field switching time, inter-particle attraction, particle attraction / repulsion, and collisions along their paths. This results in longer color switching times for color electrophoretic displays, with update rates as high as 500 milliseconds. In other words, a color electrophoretic display requires at least a 500-millisecond interval to display the next image after a color switch. Consequently, the update rate of color pen-writing traces is low, leading to a poor user experience.

[0005] Previous technologies, such as the Taiwan TWI400674B, employed a handwriting prediction method to pre-draw possible handwriting patterns, reducing the perceived latency of handwriting. However, handwriting prediction methods must promptly correct incorrect predictions. For systems where multiple color particles move and mix, particle movement is difficult. Therefore, when handwriting prediction is incorrect, the particles require even more time to re-move and rearrange. Consequently, the Taiwan TWI400674B method is not suitable for electrophoretic display systems with multiple color particles.

[0006] Therefore, providing a color electrophoresis display that does not result in a poor user experience due to pen stroke update delays remains one of the goals that the industry urgently needs to develop. Summary of the Invention

[0007] The disclosed technical embodiment is a display method for a color electrophoretic display, wherein the color electrophoretic display includes a non-color particle and a plurality of color particles.

[0008] In one embodiment, the display method of the color electrophoresis display includes activating a pen writing mode; providing a specified pen writing color; sensing the movement of a stylus to output a black pen writing trajectory, wherein the color of the black pen writing trajectory is presented by non-colored particles and colored particles approaching the top electrode, and the color update time of the black pen writing trajectory is less than 50 milliseconds; and sensing the stopping of the stylus to convert the black pen writing trajectory into a colored pen writing trajectory with the specified pen writing color, wherein the specified pen writing color and the color of the black pen writing trajectory have a change in brightness and a change in at least one of hue and chroma.

[0009] In one embodiment, the color of the black pen-written trajectory is the color with the shortest update time in the color electrophoresis display.

[0010] In one embodiment, the update time for the specified pen color is 5 to 10 times the update time for the color of the black pen trace.

[0011] In one embodiment, the non-colored particles are white, and the colored particles are cyan, yellow, and magenta.

[0012] In one embodiment, the distance between the black pen trace and the tip of the stylus is less than 3 mm.

[0013] In one embodiment, the display method of the color electrophoresis display further includes determining whether the color difference between the specified pen color and the color of the black pen trajectory is greater than 13; if so, selecting a color group with a color difference of less than 13 from the specified pen color, and then selecting the color with the shortest update time from the group, and displaying the pen trajectory with this color.

[0014] In one embodiment, the display method of the color electrophoresis display further includes sensing that the stylus has contacted the color electrophoresis display and started to move by using a pressure change from low to high between the stylus and the color electrophoresis display.

[0015] In one embodiment, the stylus is further used to sense the stylus moving away from the color electrophoretic display by utilizing a change in pressure between the stylus and the display from high to low to stop the stylus from moving away.

[0016] In one embodiment, the step of specifying the pen color occurs before or after the step of sensing pen contact.

[0017] Another technical embodiment disclosed herein is a color electrophoretic display. The color electrophoretic display includes non-color particles and multiple color particles. The non-color particles and color particles are close to the top electrode to present a writing trajectory formed by the movement of a stylus. The distance between the endpoint of the writing trajectory and the tip of the stylus is less than 3 mm. The color electrophoretic display does not include a color filter.

[0018] In the above embodiments, the display method of the color electrophoresis display first displays the black pen strokes, so the user will not perceive any delay in the pen strokes. The color development step is performed after the pen strokes are displayed. Since the black pen strokes already exist, the time delay in displaying the color is less noticeable, thus improving the user experience. Therefore, the color electrophoresis display method disclosed herein provides the effect of reducing pen stroke delay while simultaneously providing colored handwriting. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of a color electrophoresis display according to an embodiment of the present disclosure;

[0020] Figure 2 This is a cross-sectional view of a color electrophoresis display according to an embodiment of the present disclosure;

[0021] Figures 3A to 3D This is a schematic diagram showing the positions of different particles when displaying different colors on a color electrophoresis display according to an embodiment of the present disclosure;

[0022] Figure 4 A display method for a color electrophoretic display according to an embodiment of the present disclosure;

[0023] Figure 5 for Figure 4 A schematic diagram of the intermediate steps of the display method;

[0024] Figure 6 for Figure 4 A schematic diagram of the intermediate steps of the display method.

[0025] [Symbol Explanation]

[0026] 100,100a: Color electrophoresis display

[0027] 110:Substrate

[0028] 120: Bottom electrode

[0029] 130: Top electrode

[0030] 140: Electrophoretic medium

[0031] 142: White Particles

[0032] 144: Cyan Particles

[0033] 146: Yellow particles

[0034] 148: Magenta Particles

[0035] 150, 160: Adhesive layer

[0036] 170: Protective layer

[0037] 200: Stylus

[0038] 210: Black pen strokes

[0039] 220: Colored pen writing trajectory

[0040] S1~S4: Steps Detailed Implementation

[0041] The following describes several embodiments of the present invention with reference to the accompanying drawings. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and elements will be shown in the drawings in a simple schematic manner. And for clarity, the thickness of layers and regions in the drawings may be exaggerated, and the same element symbols denote the same elements in the description of the drawings.

[0042] In this document, the term "bistable" or similar terms refer to a display having first and second display states that differ in at least one optical property, which can change between the first and second display states upon receiving a driving source, and remain stable in the first and second display states. Additionally, some displays are also stable in intermediate states between the aforementioned first and second display states; such displays can be called "multistable," but for ease of understanding, the term "multistable" or similar terms in this document can encompass multistable displays.

[0043] Some embodiments of this invention are directed to electro-optic displays, particularly bistable electro-optic displays, such as an electrophoretic display using particle-reflected light, wherein one or more types of colored (black, white, or chromatic) / charged particles are present in a fluid (i.e., the electrophoretic medium hereinafter) and move within the fluid under the influence of an electric field and / or magnetic field to alter the display's appearance (or display image). A color electrophoretic display according to some embodiments of this invention has a material (i.e., colored / charged particles) capable of generating first and second display states. By applying an electric field and / or magnetic field to the material, the appearance of the material is changed from a first display state to a second display state, wherein at least one optical property (such as hue, brightness, and chroma) differs between the first and second display states.

[0044] Figure 1This is a cross-sectional view of a color electrophoretic display 100 according to an embodiment of the present disclosure. The color electrophoretic display 100 includes a substrate 110, a bottom electrode 120, a top electrode 130, and an electrophoretic medium 140. Thin-film transistors (TFTs) on the substrate 110 form an active array of pixels. The bottom electrode 120, arranged in rows and columns, serves as pixel electrodes. The intersections of the pixel electrodes correspond to the pixels displayed by the color electrophoretic display 100, thereby forming a matrix image display. An adhesive layer 150 may also be provided between the bottom electrode 120 and the electrophoretic medium 140, and an adhesive layer 160 may also be provided between the top electrode 130 and the electrophoretic medium 140. A protective layer 170 is also provided on the top electrode 130 to protect the top electrode 130.

[0045] The bottom electrode 120 and the top electrode 130 can be transparent conductors, such as indium tin oxide (ITO) or indium zinc oxide (IZO), which can be deposited on a transparent substrate, such as polyethylene terephthalate (PET) or polyimide (PI), and then formed into electrodes through a patterning step. Alternatively, the bottom electrode 120 and the top electrode 130 can be made of flexible conductive materials, such as metal nanowires (e.g., silver nanowires), conductive polymers, or polymers with conductive additives.

[0046] The electrophoretic medium 140 of the color electrophoretic display 100 in some embodiments of the present invention contains four different types of particles, each with different particle size, color, charge (positive, negative, or charged) and / or electron mobility, but is not limited thereto. In this embodiment, white particles 142, cyan particles 144, yellow particles 146, and magenta particles 148 are used as examples. White particles 142 are achromatic and reflective particles. Cyan particles 144, yellow particles 146, and magenta particles 148 are chromatic particles and are subtractive particles. The electrophoretic medium 140 is packed into microcapsules or microcups and formed onto the substrate 110 by coating, lamination, or spraying. In this embodiment, more than tens of thousands of different colors can be displayed using the above-described four-particle ink system, and each pixel of the color electrophoretic display 100 can display the full color gamut.

[0047] Figure 2This is a cross-sectional view of a color electrophoretic display 100a according to an embodiment of the present disclosure. The electrophoretic medium 140 is dispersed in microcells or cavities, the cavities being separated by a material such as a medium or polymer. The bottom electrode 120 has segmented regions corresponding to the microcells for individually driving the particles in each microcell. The color electrophoretic display of the present disclosure is not limited to the above-described form, and may be, for example, an electrophoretic display having an electrophoretic medium 140 with a combination of colorless and colored particles, such as an electrophoretic display containing black, red, green, and blue particles; or, for example, an electrophoretic display containing black, red, yellow, and blue particles; or, for example, an electrophoretic display containing black, white, red, and yellow particles.

[0048] In the field of color, "achromatic" refers to black, white, and various shades of gray. The transition from white to black involves only a change in lightness (quantified by brightness), without any change in hue (quantified by wavelength) or chroma (quantified by saturation). Using CIELAB, L* represents lightness; L*=0 represents pure black with 0% reflectance or transmittance; L*=50 represents medium gray; and L*=100 represents white, meaning 100% reflectance and sharpness. In this article, the monochrome electrophoretic display refers to an electrophoretic display with "achromatic" particles: either white or black particles. The transition from white to black in this display involves only a change in lightness (ΔL*), without any change in hue or chroma. Specifically, in a black-and-white two-color particle electrophoretic display, the driving method for the black and white particles is relatively simple. Black and white particles with opposite charges are simply brought to the viewing surface by applying two voltages of different polarities (positively or negatively charged). During the movement of these particles, a gray hue naturally appears. For example, in a white background displaying black, when switching colors (from black to white), black particles move from the display surface electrode (top electrode 130) to the driving surface electrode (bottom electrode 120), while white particles move in the opposite direction. Therefore, when the two types of particles move and mix in the electrophoretic medium 140, a gray hue naturally appears. In summary, in a black-and-white two-color particle system, the gray hue displayed is a natural phenomenon, not due to any special calculations or processing by the display system.

[0049] In contrast to achromatic white or black particles, the "chromatic" particles referred to in this article represent colored particles, such as the colors produced by colored particles reflecting light. The color changes they produce involve not only changes in brightness but also variations in hue, brightness, and chroma. Using CIELAB as an example, besides L*, a* and b* may also differ, creating color differences (i.e., ΔE, or simply color difference). For instance, when the red color produced by a single magenta particle transforms into a color composed of yellow and cyan particles, there are changes in hue, brightness, and chroma in the color field. To achieve these changes, complex driving methods must be used to control the movement and mixing of various colored particles, positioning them in the required positions to display the correct colors / images / patterns. In other words, the color electrophoretic display 100a addressed in this invention far surpasses black-and-white electrophoretic displays in both the combination of electrophoretic particles and the control of color.

[0050] For electrophoretic displays with multi-color particles, the method of driving the particles is complex. A color electrophoretic display with four-color particles can display thousands of colors by precisely controlling the relative position of each particle. One method is to provide square wave pulses through the driving circuit on the substrate 110, providing multiple sets of different voltage values ​​to arrange different particles in different ways, so that the final color to be displayed is displayed on the viewing surface. However, when there are multiple non-color particles and colored particles at the same time, even when displaying a black or white image, its response time is not as fast as that of a simple black and white electrophoretic display. One of the objectives of this invention is to solve the display delay of the color electrophoretic display 100a, especially when the color electrophoretic display 100a is used for handwriting, to provide a user-friendly display mode and minimize the user's perception of pen touch delay.

[0051] Figures 3A to 3D This is a schematic diagram showing the positions of different particles when displaying different colors on a color electrophoresis display according to an embodiment of this disclosure. The top of the diagram shows the viewing surface and the direction of light incidence. (Hereinafter referred to as...) Figure 2 Taking the electrophoretic medium 140 of the color electrophoresis display 100a as an example. Figure 3AIn the process, white particles 142 reflect light, while cyan particles 144, yellow particles 146, and magenta particles 148 are controlled by the electric field and positioned below white particles 142. White particles 142 can then reflect light from a light source (such as an ambient light source or a front light source of the color electrophoresis display 100a), causing the viewing surface (i.e., above the top electrode 130 (in the direction shown in the attached figures)) to display white. In other words, the single color (i.e., white) displayed at this time can indicate that the electric field between the bottom electrode 120 and the top electrode 130 is driven to an extreme state, causing white particles 142 to approach (or concentrate) the top electrode 130, while other particles are away from (or not approach) the top electrode 130, thus presenting a single color. Figure 3B In the image, yellow particle 146 is positioned above white particle 142. Light passes through yellow particle 146 and is reflected by white particle 142, causing the viewing surface to display yellow. Similarly, a color electrophoresis display can also display cyan, magenta, and red. Figure 3C ) and blue. Figure 3D In this embodiment, all three colored particles are positioned above the white particle 142, displaying as black. Since black is formed by mixing four particles—white particle 142, cyan particle 144, yellow particle 146, and magenta particle 148—an extreme driving method can be adopted, such as applying the maximum voltage difference. This allows the particles to move to the top electrode 130 at the fastest speed under the drive of the high voltage difference to mix the light. Because the four particles move in essentially the same direction, the aforementioned movement resistance is minimized, thereby enabling the display of black with the minimum reaction time, for example, less than 50 milliseconds.

[0052] In another embodiment, the particles of the color electrophoretic display can include non-colored black particles and colored red, blue, and green particles. Black particles absorb light, and when red, blue, and green particles are positioned below black particles, the viewing surface displays black. When red particles are positioned above black particles, the viewing surface displays red. Similarly, when blue particles are positioned above black particles, the viewing surface displays red. When green particles are positioned above black particles, the viewing surface displays green. When two colored particles are positioned above black particles, the viewing surface can display a mixed color of purple, orange, or yellow, respectively. When all three colored particles are positioned above black particles, the display is white.

[0053] The above is displayed. Figures 3A to 3D Color can be achieved in several ways. For example, one method uses differences in electrophoretic mobility to allow charged particles to move within a specific electric field. During this movement, the distribution of the particles changes, thus altering the original electric field. Therefore, by adjusting the electric field in multiple stages, the particles needed to produce the target color can be positioned close to the viewing surface.

[0054] In another embodiment, the intensity of particle aggregation can be adjusted by surface treatment of the particles. This can be achieved by forming polymers of varying thicknesses on the particle surface. For example, in this embodiment, it is assumed that white particles 142 are negatively charged, cyan particles 144 are positively charged, yellow particles 146 are negatively charged, and magenta particles 148 are positively charged. In other embodiments, the applied voltage and pulsed square wave can be adjusted accordingly when the particles carry different charges. White particles 142 and cyan particles 144 have thicker shells. Under these conditions, the interaction force between yellow particles 146 and magenta particles 148 is the strongest, requiring a higher electric field to separate them. The interaction force between white particles 142 and cyan particles 144 is the second strongest, and similar to the interaction force between cyan particles 144 and / or yellow particles 146. The interaction force between white particles 142 and cyan particles 144 is weaker, but stronger than the interaction force between particles of the same charge. Based on these characteristics, under different electric field magnitudes, specific particles can be aggregated and moved slowly, and specific charges can be moved to designated positions.

[0055] In one embodiment, the above Figures 3A to 3D The color in the image can be driven by five voltages, including two sets of positive voltages, zero voltage, and two sets of negative voltages. For example, 30 volts, 20 volts, 0 volts, -20 volts, and -30 volts can be used, but this disclosure is not limited thereto. In other embodiments, even more sets of positive and negative voltages can be used to form the desired pulse waveform to achieve the effect of driving the particles.

[0056] To display white, a square wave oscillating between 0 volts and -20 volts is applied, causing the white particles 142 to move closer to the viewing surface. To display black, a square wave oscillating between 0 volts and +20 volts is applied, causing the three colored particles to move above the white particles 142. To display color, the square wave can oscillate between different voltage values, such as between +30 volts and -20 volts or between -30 volts and +20 volts. Furthermore, the duration and frequency of the different voltage values ​​are adjusted according to the color to be displayed.

[0057] From a market trend perspective, color electrophoretic displays represent a development direction for products. However, as mentioned earlier, color electrophoretic displays, due to the larger number of internal particles (compared to monochrome electrophoretic displays) and the more complex factors influencing particle movement (such as electric field switching, inter-particle attraction, and resistance from obstacles during particle movement), experience longer color switching times, resulting in display latency. Furthermore, the integration of the display with pen writing (or other types of input) is a user-required feature, and the introduction of handwriting functionality further highlights the latency issue of color electrophoretic displays. In the aforementioned embodiment, the response time required to display black (monochrome) is shorter (i.e., faster update time / update rate, or shorter latency), less than 50 milliseconds, preferably less than 30 milliseconds; while the response time required to display color (especially colors requiring mixing of two or more particles) is longer, for example, 500 milliseconds.

[0058] In other words, color electrophoretic displays typically suffer from handwriting trajectory delay, where there is a significant time lag, or latency, between the moving input and the corresponding moving display portion of the color electrophoretic display. Therefore, handwriting requires a short update time so that users can instantly and without delay view the written handwriting. Research indicates that the human eye can discern a time difference of approximately 55–65 milliseconds; therefore, the latency should be as low as possible—less than 100 milliseconds, less than 65 milliseconds, less than 42 milliseconds, less than 30 milliseconds, and less than 20 milliseconds. The display method of the color electrophoretic display disclosed herein will be described later, providing an effect that reduces handwriting trajectory delay while simultaneously providing colored handwriting. The aforementioned color electrophoretic displays 100, 100a, and various color display methods can all be employed.

[0059] Figure 4 This disclosure describes a display method for a color electrophoretic display according to an embodiment. In step S1, a pen writing mode is activated. For example, in this embodiment, the pen writing mode of the color electrophoretic display can be achieved using a capacitive touch sensor combined with a pressure sensor. The signal from a finger and the signal from a stylus have different polarities, and non-human signals such as ghost dots and other noise do not exert pressure on the display. Therefore, the pen writing mode can distinguish between the touch signals of a finger and a stylus. The specific driving method of the pen writing mode is not limited to the above; it can be implemented as long as the display can produce a corresponding response based on the stylus on the display surface.

[0060] In another embodiment, the color electrophoretic display has an electromagnetic induction layer, which typically includes a magnetic film and an electrode grid. The stylus held by the user includes an induction coil, so that the movement of the coil during writing can be converted into position, pressure, etc., sensed by the electromagnetic induction layer, achieving the function of pen input. In this embodiment, a passive stylus (i.e., a stylus without an internal power supply) can be used, whose electric field can be sensed by the electromagnetic induction layer. This embodiment can determine the start or end of the input stroke by analyzing the pressure / electromagnetic signal data from the electromagnetic induction layer. For example, a pressure change from less than or equal to zero to greater than zero can be regarded as the start of a new stroke, while a pressure change from greater than zero to less than or equal to zero indicates the end of the stroke.

[0061] In step S1, when the stylus tip approaches the color electrophoretic display 100, 100a, the stylus generates a response signal, such as an electric field that oscillates synchronously with the resonant circuit of the electromagnetic induction layer, causing the stylus tip to approach (but not yet touch) the color electrophoretic display, thus automatically activating the pen writing mode. Alternatively, the pen writing mode can be activated by the user tapping a menu with a stylus or finger.

[0062] In step S2, the pen color is specified. The pen color can be one or more of the various colors that can be displayed by the aforementioned colored and non-colored particles. The specific number of colors that can be displayed depends on the color electrophoresis display used, but does not include black and white (non-colored), because the color rendering delay of single colors, such as black and white (non-colored), is not high. For example, by using the extreme driving method described above to control the position of the particles, when the user specifies the pen color as black or white, the color electrophoresis display can directly display the pen stroke with the specified color without performing the following color matching step.

[0063] In a broad sense, when the update rate of the color specified by the user is low (i.e., the update time is long), the color matching method of the present invention can be used; conversely, if the update rate of the color specified by the user is high (e.g., higher than the update rate that the human eye can perceive), the pen stroke can be displayed directly. Specifically, the color electrophoresis display of this embodiment has an internal lookup table (the data can be stored in the display's memory) that records the update time of each color on the display. When the user specifies a color, the controller of the color electrophoresis display performs a comparison step to find the update time of the specified color. If the update time exceeds a certain value (e.g., greater than 20 milliseconds, greater than 30 milliseconds, greater than 42 milliseconds, greater than 65 milliseconds, greater than 100 milliseconds), the color matching method of the present invention can be used. In a specific embodiment, when the update time of the specified color is greater than 50 milliseconds, the controller of the color electrophoresis display does not directly output the pen stroke trajectory, but performs the following pen stroke color matching step.

[0064] Reference Figure 5 . Figure 5 for Figure 4 This is a schematic diagram of an intermediate step in the display method. In step S3, the stylus 200 contacts or moves within the color electrophoresis display to output a black pen trace 210. The term "black pen trace" used in this embodiment does not limit the color of the pen to optically defined pure black, such as K=100 in the CMYK system. The term "black pen trace" is mainly for ease of explanation: the pen colors presented in step S3 and step S4 are different (i.e., to the human eye, one is colorless, and the other is colored). Figure 3D As shown, the three colored particles, after being mixed, are all positioned above the white particle 142, appearing as black (note that although the black in this embodiment is formed by color mixing, from the user's perspective, it is still a monochrome (colorless) color). In this embodiment, the pixels passed by the stylus 200 are displayed as black according to the aforementioned driving method, instead of directly displaying the pen color specified in step S2. Therefore, the reaction time in step S3 is less than 50 milliseconds. As mentioned above, the four particles—white particle 142, cyan particle 144, yellow particle 146, and magenta particle 148—are driven by the maximum voltage difference to move to the top electrode 130 at the fastest speed to mix the light, thereby drawing the pen stroke with the minimum reaction time, so that the human eye cannot perceive the delay.

[0065] Alternatively, the four types of particles can be made to be magnetic, so a hybrid driving mode can be used, that is, in addition to the electric field, a magnetic field can be incorporated, and the particles can be driven to move to the top electrode 130 at the fastest speed for light mixing.

[0066] Figure 5 The pixels of the black pen stroke trajectory 210 shown in the figure can be referenced. Figure 3D The cyan particle 144, yellow particle 146, and magenta particle 148 in the pixel corresponding to the black pen stroke trajectory 210 all move above the white particle 142.

[0067] In a broader sense, step S3 utilizes the color with the fastest update speed in the color electrophoresis display to prioritize the presentation of the trajectory formed by the pen stroke, allowing the user to instantly see the position / state of the pen writing. As mentioned earlier, the color electrophoresis display includes a lookup table that records the update time of each color on the display. Therefore, the control chip of the color electrophoresis display can select the color with the fastest update speed from the lookup table to prioritize the presentation of the pen stroke. There is a gap between the tip of the user's stylus / pen and the leading end of the pen stroke trajectory output by the color electrophoresis display. This gap can also represent the delay mentioned earlier. This embodiment can significantly reduce the gap, making the two as close to each other as possible. The size of the gap is positively correlated with the writing speed and the delay time. With a fixed writing speed, selecting the color with the fastest update speed (i.e., the shortest delay time) to prioritize the presentation of the pen stroke can significantly shorten the aforementioned gap, thereby better meeting the needs of pen writing. In this embodiment, since black is the display color with the highest update speed (50 milliseconds), black is used to present the pen strokes in this embodiment. The general writing speed is about 60mm / second. After calculation, the aforementioned spacing is about 3mm. That is to say, if the spacing can be controlled below 3mm, the writing delay can be effectively reduced.

[0068] Reference Figure 6 . Figure 6 for Figure 4 This is a schematic diagram of an intermediate step in the display method. Next, in step S4, the stylus 200 is sensed to move away from or stop moving, and the black writing trajectory 210 is converted into a colored writing trajectory 220 of the specified writing color selected in step S2. For example, a decrease in pressure value is used to determine that the stroke has ended, and the black writing trajectory 210 is overlaid with color so that the stroke displays the color selected by the user. In this embodiment, according to the aforementioned driving method, the pixels traversed by the stylus 200 are displayed as the writing color specified in step S2. Figure 6 A schematic diagram showing the 220 pixels of the colored pen writing trajectory is provided; the distribution of its color particles can be referenced. Figure 3C Taking red as an example, but not limited to this, the colored pen trace 220 can be a combination of one or more colors, which is the color presented by cyan particles 144, yellow particles 146, magenta particles 148 and white particles 142 moving to the top electrode in driving mode and reflecting external light source or system built-in light source; and the specified pen color has a change in brightness and at least one of hue and chroma between it and the color of the black pen trace. For example, in this embodiment, the change from black to red has a change in brightness, hue and chroma in color science. Compared with this case, the gray / grayscale presented in the previous case during the movement of black and white particles only has a change in brightness, and the grayscale of the black and white particle system is a natural phenomenon that does not require special control.

[0069] Since black pen trace 210 (e.g., the fastest updating color) is displayed first in step S3, the user will not perceive any delay in the pen trace. Step S4 immediately follows step S3, so although it takes approximately 500 milliseconds (depending on the specified color), the time delay in displaying the colored pen trace 220 is less noticeable given the existing black pen trace 210, thus improving the user experience. In one embodiment, the color selected in step S3 updates faster than the color specified in step S2. Specifically, the update time of the color specified in step S2 is approximately 5 to 10 times longer than the update time of the color selected in step S3. For example, in this embodiment, the update time for black is 50 milliseconds, while red requires 500 milliseconds.

[0070] In a variation embodiment, to avoid a significant difference between the color preferentially presented in step S3 and the color selected by the user in step S2, the color preferentially presented in step S3 will be selected to be similar to the color selected by the user in step S2, while meeting the aforementioned requirement of reducing delay. Taking color difference as a consideration, if the ΔE between two colors is less than 3.2, the human eye cannot distinguish between the two colors; if 3.2 < ΔE < 6.5, the human eye will perceive the two colors as essentially the same; if 6.5 < ΔE < 13, the human eye will perceive the two colors as having the same hue; if the ΔE between two colors is greater than 13, the human eye will perceive the two colors as having different hues. Therefore, after the user selects a color (step S2), the control chip of the color electrophoresis display can perform the following sub-steps: determine whether the color difference between the specified pen color and the color of the black pen trace is greater than 13. If so, then: find a color group from the lookup table whose ΔE between the user-selected color and the color is less than 13 (in other embodiments, it can also be set to less than 6.5 or less than 3.2), and then select the color with the fastest update speed from the group to display the pen stroke; or, if the ΔE between the colors in the lookup table and the user-selected color is greater than 13 (in other embodiments, it can also be set to greater than 6.5 or greater than 3.2), then directly use the color with the fastest update speed to display the pen stroke. Accordingly, the pen writing delay can be reduced, and the visual discomfort of the user for pen stroke color switching can be reduced.

[0071] In some embodiments, an electrophoretic display with particles of four or more colors may also be used. Since the display method disclosed herein first displays the black pen trace 210 and then displays the specified color, the time required for adjusting the multi-colored particles in step S3 is not limited, and it can still have the effect of improving the user experience.

[0072] This disclosure provides a display method for a color electrophoresis display according to another embodiment. In this embodiment, the difference from the previous embodiment is that the step of specifying the pen color can be done after the black pen trace 210 is completed.

[0073] The steps described above for converting the black pen stroke 210 into a colored pen stroke 220 include hue conversion. Hue conversion is the aforementioned step of changing the arrangement position of the colored particles. In some embodiments, it also includes lightness conversion and chroma conversion. Lightness conversion can be determined by the position of the white particles 142, which serve as a reflective layer. Chroma conversion can be determined by the position of the colored particles.

[0074] In summary, the color electrophoretic display method disclosed herein first displays the black pen strokes, so the user will not perceive any delay in the pen strokes. The color rendering step is performed after the pen strokes are displayed. Since the black pen strokes already exist, the time delay in displaying the color is less noticeable, thus improving the user experience. Therefore, the color electrophoretic display method disclosed herein provides the effect of reducing pen stroke delay while providing colored handwriting. However, another implementation of the color electrophoretic display uses color filters to create the three primary colors and then mixes them to present a color display. The color rendering in this type of color electrophoretic display does not involve the movement of multi-color particles; therefore, the color matching method of this invention may not be applicable to electrophoretic displays with color filters (but this is not excluded).

[0075] This invention mainly utilizes the color matching step to solve the color rendering delay problem caused by the movement of colored particles in a multi-color particle system. During the writing stage, the color with the shortest update time is used to present the writing trajectory, so that the user does not feel any delay. For example, the distance between the tip of the user's stylus / pen and the leading end of the pen stroke trajectory output by the color electrophoresis display is limited to less than 3mm. Subsequently, the specified color is applied to the pen stroke trajectory to present the user's pre-selected handwriting color.

[0076] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Any person skilled in the art may make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A display method for a color electrophoretic display, wherein the color electrophoretic display comprises a non-colored particle and a plurality of colored particles, wherein the non-colored particle is a white particle or a black particle, and the plurality of colored particles are at least two selected from cyan particles, yellow particles, magenta particles, red particles, blue particles, and green particles, characterized in that, The display method of this color electrophoresis display includes: S1: Enable pen writing mode; S2: Provide a specified pen color, wherein the specified pen color is one or more of a variety of colors that the colored particle and the non-colored particle can display, wherein the specified pen color does not include black and white; S3: Sensing the movement of the stylus to output a black writing trajectory, wherein the color of the black writing trajectory is determined by the non-colored particles and the plurality of colored particles approaching a top electrode, and the color update time of the black writing trajectory is less than 50 milliseconds; and S4: When the stylus stops, the black writing trajectory is converted into a colored writing trajectory with the specified writing color. The specified writing color and the color of the black writing trajectory have a change in brightness and a change in at least one of hue and chroma.

2. The display method of the color electrophoresis display as described in claim 1, characterized in that, The color of the black pen stroke is the color with the shortest update time in the color electrophoresis display.

3. The display method of the color electrophoresis display as described in claim 1, characterized in that, The update time for the specified pen color is 5 to 10 times the update time for the color of the black pen trace.

4. The display method of the color electrophoresis display as described in claim 1, characterized in that, The non-colored particle is white, and the plurality of colored particles are cyan, yellow, and magenta.

5. The display method of the color electrophoresis display as described in claim 1, characterized in that, The distance between the black pen stroke and the tip of the stylus is less than 3mm.

6. The display method of the color electrophoresis display as described in claim 1, characterized in that, Also includes: Determine if the color difference between the specified pen color and the color of the black pen trace is greater than 13; if so, proceed as follows: Select a color group whose color difference with the specified pen color is less than 13, and then select the color with the shortest update time from the group, and present the pen trajectory in the color in step S3.

7. The display method of the color electrophoresis display as described in claim 1, characterized in that, Step S3 also includes sensing that the stylus has come into contact with the color electrophoresis display and has begun to move by using the pressure change between the stylus and the color electrophoresis display from low to high.

8. The display method of the color electrophoresis display as described in claim 1, characterized in that, Step S4 also includes using the pressure change between the stylus and the color electrophoresis display from high to low to sense the stylus moving away and stop.

9. The display method of the color electrophoresis display as described in claim 1, characterized in that, Step S2 may occur before or after step S3.

10. A color electrophoretic display comprising a non-color particle and a plurality of color particles, wherein the non-color particle is a white particle or a black particle, and the plurality of color particles are at least two selected from cyan particles, yellow particles, magenta particles, red particles, blue particles, and green particles, characterized in that... The non-colored particles and the plurality of colored particles approach a top electrode and form a writing trajectory formed by the movement of a stylus. The distance between the endpoint of the writing trajectory and the tip of the stylus is less than 3 mm. The color electrophoretic display does not contain a color filter.

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