Electronic paper display driving method, chip and module

Abstract

An electronic paper display driving method, a chip and a module are used for improving edge color difference, and N rows or M columns of pixel points close to the edge are driven by a B driving waveform. The central pixel point is driven by the A driving waveform; the color particle driving time of the B driving waveform is longer than the color particle driving time of the A driving waveform; or the color particle driving voltage of the B driving waveform is higher than the color particle driving voltage of the A driving waveform. According to the technical scheme, the problem of color deviation of the edge area and the center area can be efficiently solved.

Description

Technical Field

[0001] This application belongs to the technical field of display devices, and particularly relates to an electronic paper display driving method and a display driving module. Background Art

[0002] "Electronic paper", also known as an electronic ink screen, is a display screen made using electrophoretic display technology. Multiple mixed electronic particles are placed in the same ink sac. Under the action of an electric current, multiple ink sacs are arranged and combined to form "electronic ink". Under the influence of positive and negative charges, these tiny ink sacs operate like a liquid to form various characters and patterns. Electronic paper has excellent characteristics such as ultra-low power consumption, continuous display without power consumption, and eye protection, and has the same display effect and visual experience as paper.

[0003] Electronic paper achieves the effect of displaying an image by continuously applying a driving waveform voltage to each pixel point through a driving IC chip to drive the electronic paper particles. Two-color, three-color, and four-color electronic papers all control the lifting and moving of black, white, red, and yellow particles with different charges by an external electric field to display black, white, red, and yellow display effects. The external electric field of the electronic price tag product made of electronic paper is an electric field composed of the IC chip charging the TFT pixel and the ITO of the electronic paper. The driving time of the electric field is controlled by a group of voltage driving waveforms controlled by the IC chip to achieve the display effect.

[0004] Currently, the product market and customer requirements for electronic paper applications are becoming increasingly strict. However, due to process manufacturing problems, raw material problems, water loss or other component loss at the edge of the electronic paper affecting the display effect, the specific manifestation is abnormal edge display. When there is abnormal edge display, the color at the four edges of the screen turns yellow or white (the edge of the three-color electronic paper turns white, and the edge of the four-color electronic paper turns yellow) as Figure 6 shown.

[0005] During the use of electronic paper, over time, problems such as water loss are more likely to occur in the edge area. Therefore, the color deviation between the edge area and the central area will increase over time, resulting in an aggravated problem of display color deviation.

[0006] How to efficiently and low-costly solve the above-mentioned abnormal edge display is a technical problem to be solved.

[0007] Glossary of Terms:

[0008] EPD is the abbreviation of the English "electronic paper display", and its Chinese meaning is an electronic paper mother sheet display. The meaning of the electronic paper mother sheet in this application is an electronic paper mother sheet display.

[0009] TFT is the abbreviation of "Thin Film Transistor" in English, and its Chinese meaning is thin film field effect transistor; each pixel on the TFT display is driven by a thin film transistor integrated behind it.

[0010] PET is the abbreviation of "Polyethylene terephthalate" in English, and its Chinese meaning is polyester resin film layer.

[0011] IC is the abbreviation of "Integrated Circuit" in English, and its Chinese meaning is chip.

[0012] FPC is the abbreviation of "Flexible Printed Circuit" in English, and its Chinese meaning is flexible printed circuit board.

[0013] PS is the abbreviation of "Polystyrene" in English, and its Chinese meaning is polystyrene film.

[0014] FPL is the abbreviation of "Front Plane Lamination" in English, and its Chinese meaning is front plane lamination display module.

[0015] ITO is the abbreviation of "Indium Tin Oxide" in English, and its Chinese meaning is indium tin oxide. In this application, the ITO of the electronic paper refers to that the conductive film layer material of the transparent conductive film shielding glass is mainly ITO (indium tin oxide semiconductor) film. Summary of the Invention

[0016] The present invention can avoid the same driving signal being used for the electronic paper pixels in different regions in the prior art, and cannot solve the problem of display color deviation in the edge region and the central region caused by various reasons. The driving method and module of this application can solve the problem of color deviation in the edge region and the central region.

[0017] The technical solution of this application to solve the above technical problems is an electronic paper display driving method for improving edge color difference. For the pixel points in the N rows or M columns close to the edge, they are driven by the B driving waveform; for the central pixel points, they are driven by the A driving waveform; the driving time of the color particles in the above B driving waveform is longer than that in the A driving waveform; or the driving voltage of the color particles in the B driving waveform is higher than that in the A driving waveform.

[0018] For the above B driving waveform, when driving the pixel points in the N rows or N columns at the edge, the driving time or driving voltage of the color particles = set compensation coefficient - (edge distance × gradient compensation value).

[0019] The above set compensation coefficient is related to the running time, and the longer the running time, the larger the set compensation coefficient.

[0020] The above running time is the start-up running time of the electronic paper, with the unit of days.

[0021] The above-set compensation coefficient is related to the temperature value and humidity during operation.

[0022] The above electronic paper display driving method can be that the above electronic paper is a four-color electronic paper of black, white, red, and yellow; the color particles include black particles, white particles, red particles, and yellow particles.

[0023] It can be that the above electronic paper is a three-color electronic paper of black, red, and yellow; the color particles include black particles, red particles, and yellow particles.

[0024] It can be that the above electronic paper is a two-color electronic paper of black and red; the color particles include black particles and white particles.

[0025] It can be that in the above-mentioned edge N rows or M columns, the values of N and M can be set separately.

[0026] It can be that N is equal to M.

[0027] The technical solution of the present application for solving the above technical problem can also be an electronic paper display driving chip, and the above electronic paper display driving chip is used to execute the above method.

[0028] The technical solution of the present application for solving the above technical problem can also be an electronic paper display driving module, and the above electronic paper display driving module includes at least two of the above electronic paper display driving chips, one chip is used to drive the pixel points near the edge, and one chip is used to drive the central pixel points.

[0029] The technical solution of the present application for solving the above technical problem can also be an electronic paper display driving module, and the above electronic paper display driving module is used to execute the above method.

[0030] One of the beneficial effects of the technical solution in the present application is that different driving waveforms are adopted in the edge area and the central area to make up for the color difference between the edge area and the central area.

[0031] One of the beneficial effects of the technical solution in the present application is that the driving duration is convenient to control in the driving waveform, and the color difference can be made up according to the driving duration.

[0032] One of the beneficial effects of the technical solution in the present application is that the driving voltage adjustment is convenient to control in the driving waveform, and the color difference can be made up according to the driving voltage.

[0033] One of the beneficial effects of the technical solution in the present application is that the driving time or driving voltage of the color particles = the set compensation coefficient - (edge distance × gradient compensation value), which can perform precise regulation according to the edge degree, making the color difference between different pixels smaller and the display more balanced.

[0034] One of the beneficial effects of the technical solution in this application is that the compensation coefficient is set to be related to the running time, which can solve the problem of edge color difference caused by aging during long-term operation.

[0035] One of the beneficial effects of the technical solution in this application is that the running time is the start-up running time of the electronic paper, and fine adjustment can be performed according to the actual running time.

[0036] One of the beneficial effects of the technical solution in this application is that the compensation coefficient is set to be related to the temperature value and humidity during operation, which can solve the problem of edge color difference caused by environmental condition impacts.

[0037] One of the beneficial effects of the technical solution in this application is that the electronic paper can be various different color or non-color electronic papers, and the display difference between the edge and the center area can be solved. Especially the display deviation caused by water loss at the edge.

[0038] One of the beneficial effects of the technical solution in this application is that the values of N and M can be set separately, which can more flexibly adapt to actual use, and the compensation area can be flexibly set according to actual needs. When the values of N and M are equal, square area control is performed.

[0039] One of the beneficial effects of the technical solution in this application is that the electronic paper display driving chip can be integrated to solve the problem, and the cost is lower.

[0040] One of the beneficial effects of the technical solution in this application is that the electronic paper display driving module can be modularized to provide a solution, which is convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of an electronic paper pixel array;

[0042] Figure 2 It is a schematic diagram of the connection between an electronic paper display screen and a driving module;

[0043] Figure 3 It is a schematic diagram of an electronic paper pixel array;

[0044] Figure 4 It is a schematic diagram of the module of an electronic paper display driving chip;

[0045] Figure 5 It is a schematic diagram of an electronic paper display device;

[0046] Figure 6 It is a schematic diagram of an electronic paper display device;

[0047] Figure 7 It is a schematic diagram of a driving waveform;

[0048] Figure 8 It is a schematic diagram of a driving waveform;

[0049] Figure 9 It is a schematic diagram of a driving waveform. Specific embodiments

[0050] The following further details the embodiments of the present invention in conjunction with the accompanying drawings.

[0051] It should be noted that the following is a description of the preferred embodiments of this application, which does not constitute any limitation to this application. The description of the preferred embodiments of this application is only for the description of the general principles of this application. The embodiments described in this application are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0052] In the description of this application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to this application. In addition, terms such as "first" and "second", as well as technical features numbered with Arabic numerals such as 1, 2, 3, etc., and numbers such as "A" and "B", are only for descriptive purposes, only for the convenience of description, and do not represent a time or spatial sequence relationship; it cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second", as well as those numbered with Arabic numerals such as 1, 2, 3, etc., may explicitly or implicitly include one or more of such features. In the description of this application, the meaning of "several" is two or more, unless otherwise specifically defined.

[0053] As Figure 6 shown, in the prior art, when there is an abnormal edge display of an electronic paper, the color of the four edges of the screen turns yellow or white; for a three-color electronic paper, the edge is white, and for a four-color electronic paper, the edge turns yellow.

[0054] As Figure 2 , in an embodiment of an electronic paper display driving method for improving edge color difference, the pixel points in the N rows or M columns close to the edge are driven by a B driving waveform; the central pixel points are driven by an A driving waveform; the driving time of the color particles of the above B driving waveform is longer than that of the color particles of the A driving waveform; or the driving voltage of the color particles of the B driving waveform is higher than that of the color particles of the A driving waveform.

[0055] The fact that the driving voltage of the color particles in the B driving waveform is higher than that in the A driving waveform means that the voltage for maintaining the driving of the target color particles is higher. Specifically, as Figure 7 shown, the driving voltage EB of the B driving waveform is greater than the driving voltage EA of the A driving waveform.

[0056] The fact that the driving time of the color particles in the B driving waveform is longer than that in the A driving waveform means that the time for maintaining the driving of the target color particles is longer. Specifically, there are various implementation manners. One of them is, as Figure 8 shown, within the same period, the time for maintaining the driving level of the square wave is longer. Figure 8 In Figure 9 shown, the maintaining time of the driving period TB of the B driving waveform is greater than the maintaining time of the driving period TA of the A driving waveform. One of them is, as Figure 9 shown, within the same period or time period, the number of frames for maintaining the driving level of the square wave is more, so that the total driving time is longer.

[0057] As Figure 2 shown, for the electronic paper display driving module, there are two sub-modules inside the driving module, one for edge driving and one for center driving. The B driving waveform comes from the edge driving sub-module and is used to drive the pixels at the edge; the A driving waveform comes from the center driving sub-module and is used to drive the pixels in the center area.

[0058] In some embodiments not shown in the drawings, for the above-mentioned B driving waveform, when driving the pixels in N rows or N columns at the edge, the driving time or driving voltage of the color particles = set compensation coefficient - (edge distance × gradient compensation value).

[0059] For example: the set compensation coefficient is 10, the gradient compensation value is 1, and the edge distance is 1. The first edge compensation time is equal to 10 - 1×1 = 9. The first edge compensation time is used as the driving time of the color particles.

[0060] For example: the set compensation coefficient is 10, the gradient compensation value is 1, and the edge distance is 2. The second edge compensation time is equal to 10 - 2×1 = 8. The larger the edge distance value, the closer it is to the edge, the greater the water loss degree, and the greater the compensated value. The second edge compensation time is used as the driving time of the color particles.

[0061] The driving time and driving voltage of the color particles can have different set compensation coefficients, which can be measured or selected according to the actual application situation.

[0062] The compensation coefficient and the gradient compensation value can be set according to the specific situation of the electronic paper. The greater the difference gradient between the edge area and the central area, the greater the compensation coefficient and the gradient compensation value can be set.

[0063] In some embodiments not shown in the drawings, the above-mentioned set compensation coefficient is related to the running time. The longer the running time, the greater the set compensation coefficient. The above-mentioned running time is the start-up running time of the electronic paper, and the unit is days.

[0064] For example, after the electronic paper display module starts running and is exposed to the air, as it ages over time and loses more moisture, the compensation value is greater. For example, the set compensation coefficient is 10 + the number of running days × 0.01. When running for 100 days, the set compensation coefficient = 10 + 100 × 0.01 = 11.

[0065] In some embodiments not shown in the drawings, the above-mentioned set compensation coefficient is related to the temperature value and humidity during operation. After the electronic paper display module starts running and is exposed to the air, the higher the temperature value it experiences, the more moisture it loses. The humidity value at the running location also affects the degree of moisture loss. For example, the set compensation coefficient = 10 + (the total running temperature × the temperature compensation coefficient), and the temperature compensation coefficient is 0.0001. For example, when running in an environment of 30 degrees for 100 hours, the compensation coefficient is 10 + (30 × 100 × 0.0001), and the compensation coefficient = 10 + 50 × 100 × 0.0001 = 10.3. For example, when running in an environment of 50 degrees for 100 hours, the compensation coefficient is 10 + (50 × 100 × 0.0001), and the compensation coefficient = 10 + 50 × 100 × 0.0001 = 10.5. Usually, the running temperature range is 30 - 40 degrees, and in some harsher environments, it may exceed this temperature range.

[0066] In some embodiments, the above-mentioned electronic paper is a four-color electronic paper of black, white, red, and yellow; the color particles include black particles, white particles, red particles, and yellow particles;

[0067] In some embodiments, the above-mentioned electronic paper is a three-color electronic paper of black, red, and yellow; the color particles include black particles, red particles, and yellow particles;

[0068] In some embodiments, the above-mentioned electronic paper is a two-color electronic paper of black and red; the color particles include black particles and white particles.

[0069] In some embodiments, in the above-mentioned edge N rows or M columns, the values of N and M can be set respectively. As Figure 3 shown, the values of N and M are equal and can be 8, that is, the 8 rows and 8 columns of pixels at the edge are supplemented and driven. It can also be other multiples of 8, such as the 16 rows and 16 columns of pixels at the edge are supplemented and driven. In practical applications, the values of N and M can be different. Of course, they can also be other values.

[0070] For example Figure 4 Figure 4 An embodiment of an electronic paper display driving chip is used to execute the above method. The electronic paper display driving chip includes a Gate buffer for outputting a Gate driving signal, a Source buffer for outputting a Source driving signal, and a Border for outputting a Border signal; a B driving waveform data module, an A driving waveform data module, a waveform selection module, a VCOM module, a waveform setting module, and a RAM.

[0071] The waveform setting module is electrically connected to the B driving waveform data module and the A driving waveform data module; the waveform selection module controls waveform selection according to an IC instruction, and can obtain corresponding driving waveform data from the B driving waveform data module or the A driving waveform data module. The IC instruction control can select corresponding driving waveform data according to a real-time set edge area or a preset edge area range. According to different driving waveform data, corresponding Gate driving signals, Source driving signals, and Border signals are output to realize the driving time control of corresponding color particles.

[0072] In an embodiment of an electronic paper display driving module, the above electronic paper display driving module includes at least two electronic paper display driving chips, one chip for driving pixel points near the edge, and one chip for driving central pixel points.

[0073] An embodiment of an electronic paper display driving module can be a circuit module in a non-chip integration manner; the electronic paper display driving module is used to execute the above method.

[0074] The method provided by the present invention can solve the color difference within the screen and ensure a good display effect. This application is an efficient and economical solution based on the existing product architecture. During use, the display effect can be changed by adjusting the driving signal output by the driving chip to counteract the display unevenness problem between the central area and the edge area after long-term use and aging of the display.

[0075] The display effect of an electronic paper product depends on the driving voltage waveform of the IC chip of the electronic paper module (EPD) to drive the display effect of the particles in the electronic paper, and the driving waveform is determined by the charging voltage time of the IC scanning control TFT. In the prior art, only one set of waveforms, such as waveform A, can be output each time in the IC to control the color of the entire screen refresh, and it is impossible to be compatible with the problem of inconsistent colors of the screen itself.

[0076] The present invention can optionally use two sets of waveforms to separately drive the waveforms of the screen edge and the middle, so as to reduce the optical difference between the screen edge and the middle and make the display effects consistent.

[0077] For example Figure 1As shown, it is a schematic wiring diagram of the TFT wiring and TFT pixels of an e-paper. When the IC chip scans the edge regions of G1 - G16, Gm - Gm-16, S1 - S16, Sn - S16, different driving waveforms, namely B driving waveforms, are used to drive the corresponding TFT pixels for screen refreshing, which can solve the problems of edge yellowing and whitening, and can completely improve and ensure the consistency of the effects in the middle and edge regions of the screen.

[0078] As Figure 4 shown, it is an internal framework diagram of an e-paper display driving chip. It can be seen that two different B driving waveform data and A driving waveform data can be placed inside the IC chip. The B driving waveform only needs to slightly adjust and modify the driving time (number of frames) or voltage magnitude of some target color particles on the basis of the A driving waveform. The target color particles can be red particles or any one or more of other color particles.

[0079] For example: In some embodiments, the optical L value in the middle of the screen is 24.15, the A value is 36.5, the optical L value at the edge is 27.2, and the A value is 34.2. At this time, the optical difference between the edge and the middle of the screen is close to about 3 points. Then, at this time, for the B driving waveform in the edge region, i.e., the B region, only need to increase the red voltage by about 0.6 - 1.2V, and it can be reduced to an L value of 24.3 and an A value of 36.7, so that the optics of the middle and the edge are kept consistent.

[0080] As Figure 3 shown, the method in this application can be controlled by the IC chip for the edge region and the central region. It does not limit the size of the edge region to G9 / S8 or G16 / S16. The IC can set the starting and ending positions of Gate and source to control and improve the size from the edge position to the middle position of the TFT pixels with edge whitening, and use the corresponding driving waveform voltages for screen refreshing respectively. The waveform in the B region needs to be slightly adjusted based on the waveform in the A region to keep the screen refreshing effect mode consistent and not cause different visual effects that affect the experience.

[0081] As Figure 6 shown in the e-paper display, it can be seen that the edge of the red color is white or yellowish. The effect after driving by the method of this application is as Figure 5 shown, the red color maintains the same effect throughout the screen.

[0082] As shown in the accompanying drawings, the above are only embodiments of the present invention. Therefore, it does not limit the patent scope of the present invention. Any equivalent structural or equivalent process transformation made by using the content of the invention specification and the accompanying drawings, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. An electronic paper display driving method for improving edge color difference, characterized in that: The pixels in N rows or M columns close to the edge are driven by the B driving waveform; The center pixel is driven by the A driving waveform; The color particle driving time of the B driving waveform is longer than that of the A driving waveform; or the color particle driving voltage of the B driving waveform is higher than that of the A driving waveform.

2. The electronic paper display driving method according to claim 1, characterized in that: The B driving waveform, when driving N rows or N columns of pixels at the edge, the color particle driving time or driving voltage = the set compensation coefficient - (edge ​​distance × gradient compensation value).

3. The electronic paper display driving method according to claim 2, characterized in that: The set compensation coefficient is related to the running time. The longer the running time is, the larger the set compensation coefficient is.

4. The electronic paper display driving method according to claim 3, characterized in that: The running time is the startup running time of the electronic paper, in days.

5. The electronic paper display driving method according to claim 3, characterized in that: The set compensation coefficient is related to the temperature value and humidity during operation.

6. The electronic paper display driving method according to claim 1, characterized in that: Include any of the following technical features: TA1: The electronic paper is black, white, red and yellow four-color electronic paper; the color particles include black particles, white particles, red particles and yellow particles; TA2: The electronic paper is black, red and yellow three-color electronic paper; the color particles include black particles, red particles and yellow particles; TA3: The electronic paper is black and red electronic paper; the color particles include black particles and white particles.

7. The electronic paper display driving method according to claim 1, characterized in that: Include any of the following technical features: TB1: In the edge N rows or M columns, the N and M values ​​can be set separately; TB2: N equals M.

8. An electronic paper display driver chip, characterized in that: The electronic paper display driver chip is used to execute the method according to any one of claims 1 to 7.

9. An electronic paper display driving module, characterized in that: The electronic paper display driving module comprises at least two electronic paper display driving chips as claimed in claim 8, one chip is used to drive the pixel points close to the edge, and the other chip is used to drive the central pixel point.

10. An electronic paper display driving module, characterized in that: The electronic paper display driving module is used to execute the method according to any one of claims 1 to 7.

Images