Low power consumption driving method of electrophoretic electronic paper

Abstract

The present application relates to a kind of electrophoretic electronic paper low-power consumption driving method, belong to electrophoretic electronic paper driving field.It includes: first apply activation voltage then apply erase voltage, reduce once screen flicker, while reducing the span of voltage reduces the system power consumption.In the activation phase according to the activity degree of positive particle and negative particle, set 0V voltage, duration TX, while reducing the span of voltage in the activated microcapsule, reduce the system power consumption.Erasure phase is used to erase original image and carry out direct current balance compensation, according to the stable time of charged particle after the end of erasing phase, set 0V voltage, duration TY in erasure phase, avoid the aggregation of electrophoretic particle, make electrophoretic particle be in stable reference gray scale, weaken ghost phenomenon, reduce the span of voltage reduces the system power consumption.Display stage applies different voltage to control electronic paper to display different gray scale.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electrophoretic electronic paper driving, and particularly relates to a low-power driving method for electrophoretic electronic paper, and particularly relates to a low-power, flicker-reducing, residual image-weakening and direct current balancing driving method for electrophoretic electronic paper. BACKGROUND

[0002] As a kind of flat display technology, electrophoretic electronic paper has unique advantages in display. One of its most significant advantages is low power consumption. Electrophoretic electronic paper only consumes energy when particles migrate during image display, which greatly reduces energy consumption compared with liquid crystal displays that require continuous backlight, making it popular in applications such as e-book readers that require long-term use. However, due to hardware technology limitations, electrophoretic electronic paper still has a series of problems, such as high power consumption in the driving system, long-term direct current imbalance of the driving waveform that can cause damage to the display screen, and inaccurate gray scale display.

[0003] The structure of electrophoretic electronic paper mainly includes tiny particles, transparent electrodes and a suspension medium. Tiny particles are the core component of electronic paper, usually micron-sized solid particles. These particles are suspended in a liquid medium, forming the display layer of the electronic paper. The two sides are coated with transparent electrodes to create an electric field in the display layer. This electric field controls the position of the particles by adjusting their charge state, thus achieving the display effect. The presence of transparent electrodes allows light to pass through, so that the electronic paper can be seen when displaying. For electrophoretic electronic paper, when an electric field is applied to the transparent electrode, the particles will move in the liquid according to their charge state, changing the color of the display area. By adjusting the intensity and polarity of the electric field, different degrees of particle migration can be achieved to produce gray scale effects.

[0004] The driving waveform of traditional electrophoretic electronic paper generally includes an erase phase, an activation phase and a write phase. Due to the large voltage span in the traditional driving waveform, based on peak power P∝C×f×(△V) 2 ×Vsource, it will cause large system power consumption. For low-power driving waveform, it is necessary to reduce the voltage span while ensuring direct current balance and display effect to avoid damage to the electronic paper screen. SUMMARY

[0005] The purpose of the present application is to provide a low-power driving method for electrophoretic electronic paper, which can solve the problem of high power consumption of the driving system of electrophoretic electronic paper, and has the effect of reducing the number of screen flickers and improving residual images, while ensuring direct current balance to prevent ion accumulation from damaging the electronic paper display.

[0006] To achieve the above purpose, the technical solution of the present application is: a low-power driving method for electrophoretic electronic paper, comprising:

[0007] applying an erase voltage to the electrodes of the electrophoretic electronic paper, driving the negatively charged particles in the microcapsule to move towards the common electrode, and driving the positively charged particles to move towards the pixel electrode;

[0008] applying an activation voltage to the electrodes of the electrophoretic electronic paper, driving the charged particles in the microcapsule to have sustained back-and-forth collision and oscillation between the pixel electrode and the common electrode;

[0009] applying a display voltage to the electrodes of the electrophoretic electronic paper, driving the charged particles in the microcapsule to move towards the pixel electrode and the common electrode to reach a target gray scale.

[0010] In an embodiment of the present application, the activation voltage is applied to the electrodes of the electrophoretic electronic paper first, and then the erase voltage is applied, so that the one-time flicker and the one-time voltage reversal are reduced, and the system power consumption is reduced.

[0011] In an embodiment of the present application, the activation voltage is applied, that is, a positive voltage V0 is first applied to the pixel electrode for a duration TB1, then a 0V voltage is applied for a duration TX, the voltage span is reduced, and the system power consumption is reduced; finally, a negative voltage V1 is applied for a duration TC1.

[0012] In an embodiment of the present application, the erase voltage is applied, that is, a negative voltage V1 is applied to the pixel electrode for a duration TA1, driving the negatively charged particles in the microcapsule to move towards the common electrode; then a 0V voltage is applied for a duration TY, the voltage span from the erase stage to the display stage is reduced, the system power consumption is reduced, the charged particles tend to be stable to form more accurate reference gray scales, and the residual image phenomenon is weakened.

[0013] In an embodiment of the present application, the display voltage is applied, that is, according to the target gray scale to be displayed, a positive voltage V0 is applied to the pixel electrode for a duration TD1.

[0014] In an embodiment of the present application, the V0 and the V1 are both greater than the driving threshold voltage of the positive and negative particles, and the size is equal and the polarity is opposite.

[0015] In an embodiment of the present application, according to the activity degree of the positively charged particles and the negatively charged particles, the duration TX of the 0V voltage is set, when the activity degree of the positively charged particles is greater than the activity degree of the negatively charged particles, TB1+TX=TC1; when the activity degree of the positively charged particles is less than the activity degree of the negatively charged particles, TB1=TX+TC1; and if the activity degree of the positively charged particles is equal to the activity degree of the negatively charged particles, TB1=TC1.

[0016] In an embodiment of the present application, the positive particles and the negative particles reach a stable state within a predetermined time after the end of the application of the erasing voltage, and the duration TY of the 0V voltage is set according to the stable time of the charged particles, and TA1=TB1+TD1-TC1 according to the direct current balance.

[0017] Compared with the prior art, the present application has the following beneficial effects: the present application applies the activation voltage first and then applies the erasing voltage, thereby reducing the one-time flicker and the one-time voltage reversal, and reducing the power consumption of the system; on the basis of driving the positive particles and the negative particles to apply the same length of voltage with opposite polarities in the activation stage, the present application reduces the appropriate length of positive voltage or negative voltage and replaces it with 0V voltage according to the activity of the positive and negative particles at the voltage reversal, thereby reducing the voltage span and reducing the power consumption of the system; in the erasing stage, the present application controls the current balance of the entire waveform by controlling the duration of the driving voltage, and increases the appropriate length of 0V voltage for buffering in the erasing stage, thereby obtaining a stable reference gray scale, weakening the residual image, reducing the voltage span between the display stage, and reducing the power consumption of the system. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Figure 1 is a schematic diagram of the microcapsule structure of a black-and-white electrophoretic display screen;

[0019] Figure 2 Figure 4 is a traditional driving waveform diagram;

[0020] Figure 3 Figure 5 is a driving waveform diagram of an embodiment of the present application. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be specifically described below with reference to the accompanying drawings.

[0022] The present application provides a low-power driving method for electrophoretic electronic paper, comprising:

[0023] applying an erasing voltage to the electrodes of the electrophoretic electronic paper to drive the negative particles in the microcapsules to move towards the common electrode and drive the positive particles to move towards the pixel electrode;

[0024] applying an activation voltage to the electrodes of the electrophoretic electronic paper to drive the charged particles in the microcapsules to undergo continuous back-and-forth collision and oscillation between the pixel electrode and the common electrode;

[0025] applying a display voltage to the electrodes of the electrophoretic electronic paper to drive the charged particles in the microcapsules to move towards the pixel electrode and the common electrode to reach the target gray scale.

[0026] The following is a specific implementation example of the present application.

[0027] The low-power driving method of the black-and-white electrophoretic electronic paper of the embodiment comprises the following steps in sequence:

[0028] The activation voltage is applied first and then the erasing voltage is applied, so that the one-time flicker and the one-time voltage reversal are reduced, and the system power consumption is reduced.

[0029] In the activation stage, a positive voltage V0 is first applied to the pixel electrode, and the duration is TB1, so as to drive the black particles to move towards the common electrode; then 0V is applied, and the duration is TX, so as to reduce the voltage span and reduce the system power consumption; finally, a negative voltage V1 is applied, and the duration is TC1, so as to drive the white particles to move towards the common electrode.

[0030] In the erasing stage, a negative voltage V1 is applied to the pixel electrode, and the duration is TA1, so as to drive the white particles in the microcapsule to move towards the common electrode; then 0V is applied, and the duration is TY, so as to reduce the voltage span from the erasing stage to the display stage, reduce the system power consumption, make the charged particles tend to be stable to form more accurate reference gray scale, and weaken the residual image phenomenon.

[0031] In the display stage, the voltage corresponding to the time is applied to the pixel electrode plate according to the target gray scale. A positive voltage V0 is applied to the pixel electrode, and the duration is TD1.

[0032] The TA1, TB1, TC1 and TD1 satisfy the following relationship:

[0033] TA1+TC1=TB1+TD1

[0034] The TB1, TX and TC1 satisfy the following relationship:

[0035] TB1+Tx=TC1

[0036] In the embodiment, the TA1, TB1, TC1 and TD1 satisfy the formula, so that the driving waveform of the embodiment satisfies direct current balance, so as to prevent the accumulated residual charge from causing damage to the electrophoretic screen.

[0037] The electrophoretic particles are positively charged black particles and negatively charged white particles.

[0038] The TB1 is the time for the black particles to reach the extreme optical state.

[0039] The TC1 is the time for the white particles to reach the extreme optical state.

[0040] The TY is the time for the black and white particles to reach the stable state.

[0041] The black and white electrophoretic particles are in the same electric field, the activity of the black particles is higher than that of the white particles, and the movement speed of the black particles is greater than that of the white particles, so that TB1<TC1.

[0042] It should be pointed out finally that the above embodiments are used for black and white electrophoretic particles but are not limited to black and white electrophoretic particles, and the above embodiments are only used to illustrate the technical solutions of the present application but not to limit the same. Although the present application has been described in detail with reference to the above embodiments, it should be understood by those of ordinary skill in the art that modifications or equivalent replacements can still be made to the specific embodiments of the present application after reading the present application specification, but these modifications or replacements do not deviate from the scope of protection of the present application.

Claims

1. A low-power driving method for electrophoretic electronic paper, characterized in that: include: Applying an erase voltage to the electrodes of the electrophoretic electronic paper drives the negatively charged particles in the microcapsules to move toward the common electrode and drives the positively charged particles to move toward the pixel electrode; Applying an activation voltage to the electrodes of the electrophoretic electronic paper drives the charged particles in the microcapsules to continuously collide and oscillate between the pixel electrode and the common electrode; Applying display voltage to the electrodes of the electrophoretic electronic paper drives the charged particles in the microcapsules to move toward the pixel electrodes and the common electrode to achieve the target grayscale; Applying an activation voltage and then an erasing voltage to the electrodes of the electrophoretic electronic paper; The activation voltage is applied, that is, a positive voltage V0 is first applied to the pixel electrode for a duration of TB1; then a 0V voltage is applied for a duration of TX; and finally a negative voltage V1 is applied for a duration of TC1; According to the activity level of positively charged particles and negatively charged particles, the duration TX of the 0V voltage is set. When the activity level of positively charged particles is greater than that of negatively charged particles, TB1+TX=TC1; when the activity level of positively charged particles is less than that of negatively charged particles, TB1=TX+TC1; if the activity level of positively charged particles is equal to that of negatively charged particles, TB1=TC1.

2. The low-power driving method for electrophoretic electronic paper according to claim 1, characterized in that: The erasing voltage is applied, that is, a negative voltage V1 is applied to the pixel electrode for a duration of TA1 to drive the negatively charged particles in the microcapsule to move toward the common electrode; and then a 0V voltage is applied for a duration of TY.

3. The low-power driving method for electrophoretic electronic paper according to claim 1, characterized in that: The display voltage is applied, that is, a positive voltage V0 is applied to the pixel electrode according to the target gray scale to be displayed, and the duration is TD1.

4. The low-power driving method for electrophoretic electronic paper according to claim 2, characterized in that: The display voltage is applied, that is, a positive voltage V0 is applied to the pixel electrode according to the target gray scale to be displayed, and the duration is TD1.

5. The low-power driving method for electrophoretic electronic paper according to claim 2, characterized in that: Both V0 and V1 are greater than the driving threshold voltages of the positive and negative particles, are equal in magnitude, and have opposite polarities.

6. The low-power driving method for electrophoretic electronic paper according to claim 4, characterized in that: After the erase voltage is applied, the positively charged particles and the negatively charged particles will each reach a stable state within a predetermined time. The duration TY of the 0V voltage is set according to the stabilization time of the charged particles. According to the DC balance, TA1=TB1+TD1-TC1.

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