Display device, display method, and display program

Abstract

The present invention provides a display device, a display method, and a display program that can reduce power consumption in a display panel that displays an image using multiple color particles of different colors. [Solution] The display processing unit 211 displays an image on the display panel 10 by applying a voltage corresponding to the display color of each pixel to the first electrode. The switching processing unit 213 switches between a two-color display mode, which displays two colors using two types of color particles, and a multi-color display mode, which displays three or more colors using three or more types of color particles. In the multi-color display mode, the display processing unit 211 performs an inversion operation for a predetermined period, inverting the polarity of the voltage applied to the first electrode at a predetermined cycle, and then applies a voltage corresponding to the display color of the pixel to the first electrode. In the two-color display mode, the display processing unit 211 omits the inversion operation, or performs the inversion operation for a shorter period than the predetermined period, and then applies a voltage corresponding to the display color of the pixel to the first electrode.

Description

TECHNICAL FIELD

[0001] The present invention relates to a technology for displaying an image using a plurality of color particles of different colors.

BACKGROUND ART

[0002] Conventionally, electronic paper is known as a display device that is rewritable many times and has low power consumption. Electronic paper is a display device that displays an image by applying a voltage to a display panel on which a plurality of color capsules containing a plurality of color particles of different colors are arranged to move the color particles. In the electronic paper, for example, a technology for displaying a color image (multicolor display) is known by alternately applying positive-polarity voltage and negative-polarity voltage in a short cycle to three types of color particles including positively charged color particles and negatively charged color particles (see, for example, Patent Document 1).

PRIOR ART DOCUMENTS

PATENT DOCUMENTS

[0003]

PATENT DOCUMENT 1

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] However, in the conventional technology, it is necessary to perform an inversion operation that alternately applies a positive-polarity voltage and a negative-polarity voltage when rewriting an image, which causes a problem of increased power consumption.

[0005] An object of the present disclosure is to provide a display device, a display method, and a display program capable of reducing power consumption in a display panel that displays an image using a plurality of color particles of different colors.

MEANS FOR SOLVING THE PROBLEMS

[0006] A display system according to one aspect of the present disclosure comprises a display panel, a display processing unit, and a switching processing unit. The display panel has a plurality of pixels, each containing a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more color particles of different colors that are placed between the first electrode and the second electrode. The display processing unit displays an image on the display panel by applying a voltage corresponding to the display color of each pixel to the first electrode. The switching processing unit switches between a two-color display mode, which displays two colors using two types of color particles, and a multi-color display mode, which displays three or more colors using three or more types of color particles. In the multi-color display mode, the display processing unit performs an inversion operation for a predetermined period, inverting the polarity of the voltage applied to the first electrode at a predetermined interval, and then applies a voltage corresponding to the display color of the pixel to the first electrode. In the two-color display mode, the display processing unit omits the inversion operation, or performs the inversion operation for a shorter period than the predetermined period, and then applies a voltage corresponding to the display color of the pixel to the first electrode.

[0007] Another aspect of the present disclosure relates to a display method in which an image is displayed by applying a voltage corresponding to the display color of each pixel to the first electrode in a display panel in which a plurality of pixels are arranged, each pixel having a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more types of color particles of different colors that are sandwiched between the first electrode and the second electrode. In the display method, one or more processors perform the following actions: switching between a two-color display mode in which two colors are displayed using two types of color particles and a multi-color display mode in which three or more colors are displayed using three or more types of color particles; in the multi-color display mode, performing an inversion operation in which the polarity of the voltage applied to the first electrode is reversed at a predetermined period, and then applying a voltage corresponding to the display color of the pixel to the first electrode; and in the two-color display mode, either omitting the inversion operation or performing the inversion operation for a shorter period than the predetermined period, and then applying a voltage corresponding to the display color of the pixel to the first electrode.

[0008] Another aspect of the present disclosure relates to a display program that displays an image on a display panel in which a plurality of pixels are arranged, each containing a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more color particles of different colors that are placed between the first electrode and the second electrode, by applying a voltage corresponding to the display color of each pixel to the first electrode. The display program is a program that causes one or more processors to perform the following actions: switching between a two-color display mode that displays two colors using two types of color particles and a multi-color display mode that displays three or more colors using three or more types of color particles; in the case of the multi-color display mode, performing an inversion operation to reverse the polarity of the voltage applied to the first electrode at a predetermined period, and then applying a voltage corresponding to the display color of the pixel to the first electrode; and in the case of the two-color display mode, omitting the inversion operation, or performing the inversion operation for a period shorter than the predetermined period, and then applying a voltage corresponding to the display color of the pixel to the first electrode. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a display device, a display method, and a display program that can reduce power consumption in a display panel that displays an image using multiple color particles of different colors. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic cross-sectional view showing the structure of an electronic paper according to an embodiment of this disclosure. [Figure 2] Figure 2 is an enlarged view showing the pixel configuration of an electronic paper according to an embodiment of this disclosure. [Figure 3] Figure 3 shows a method for displaying an image on electronic paper according to an embodiment of this disclosure. [Figure 4] Figure 4 shows a specific example of a driving voltage applied to a pixel in an electronic paper according to an embodiment of this disclosure. [Figure 5] Figure 5 shows a specific example of a driving voltage applied to a pixel in an electronic paper according to an embodiment of this disclosure. [Figure 6] Figure 6 is a block diagram showing the configuration of an electronic paper according to an embodiment of this disclosure. [Figure 7] Figure 7 shows a display method for a two-color display mode in an electronic paper according to an embodiment of this disclosure. [Figure 8] Figure 8 shows a display method for a two-color display mode in an electronic paper according to an embodiment of this disclosure. [Figure 9] Figure 9 is a flowchart showing an example of the steps for image display processing performed in the electronic paper according to the embodiment of this disclosure. [Modes for carrying out the invention]

[0011] The embodiments of this disclosure will be described below with reference to the attached drawings. Note that the following embodiments are merely examples of the embodiments of this disclosure and do not limit the technical scope of this disclosure.

[0012] The display system described herein is a system that displays an image by applying a voltage to a display panel in which multiple pixels, each containing multiple color particles of different colors, are arranged, thereby moving the color particles. In this embodiment, electronic paper is given as an example of the display system.

[0013] [Configuration of the Electronic Paper 100] An electronic paper 100 according to one embodiment of the present disclosure will be described with reference to Figures 1 to 9. Figure 1 is a schematic cross-sectional view showing the structure of the electronic paper 100 according to one embodiment of the present disclosure.

[0014] As shown in Figure 1, the electronic paper 100 functions as a display device that displays images. The electronic paper 100 is an example of the display device of the present disclosure. Specifically, the electronic paper 100 includes a display panel 10 and a control device 20. The control device 20 controls various operations of the electronic paper 100. As the control device 20 controls the display panel 10, the electronic paper 100 displays a predetermined image. The electronic paper 100 is used, for example, as an electronic shelf label, an electronic advertisement, an e-book terminal, or an electronic notebook. The electronic paper 100 may also be used as a device other than an electronic shelf label, electronic advertisement, e-book terminal, and electronic notebook.

[0015] The electronic paper 100 includes a housing 1, a display panel 10, and a control device 20. The housing 1 accommodates the display panel 10 and the control device 20. The housing 1 has an opening 1a on the front face.

[0016] The display panel 10 displays an image in accordance with display processing by the control device 20. The display panel 10 is formed larger than the opening 1a of the housing 1, and is arranged so as to cover the opening 1a. A region of the display panel 10 corresponding to the opening 1a is a display region where an image is visually recognized by a user.

[0017] The display panel 10 is a display in which a plurality of pixels are arranged, each pixel including a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more types of color particles of different colors sandwiched between the first electrode and the second electrode. Specifically, the display panel 10 includes a first substrate 11 on the display surface side, a second substrate 12 on the non-display surface side arranged to face the first substrate 11, a common electrode 14 on the display surface side, pixel electrodes 15 on the non-display surface side, and a plurality of pixels 13 each including three or more types of color particles 16 of different colors.

[0018] The first substrate 11 is formed of a transparent plate member or sheet member such as glass or resin. On the outer surface of the first substrate 11 (the side opposite to the second substrate 12), an antireflection film may be formed, or a water-repellent treatment may be applied. The second substrate 12 is formed of a plate member or sheet member such as glass or resin.

[0019] The pixels 13 are arranged in a matrix in the row direction and the column direction on the display panel 10. On the first substrate 11 side, a common electrode 14, which is an electrode common to the plurality of pixels 13 and is a transparent electrode layer (e.g., ITO) extending to cover the entire display region, is disposed. That is, one common electrode 14 is provided for all the pixels 13, and is grounded to have a ground potential. On the second substrate 12 side, a plurality of pixel electrodes 15 corresponding to the respective pixels 13 are disposed. The pixel electrodes 15 are formed in a substantially rectangular shape in plan view, and are arranged in plurality. For example, the plurality of pixel electrodes 15 are arranged adjacent to each other with a predetermined gap therebetween. Color particles 16 are disposed between the common electrode 14 and the pixel electrodes 15. That is, each pixel 13 is constituted by the common electrode 14, the pixel electrode 15, and the color particle 16.

[0020] Each pixel 13 is driven by the difference (potential difference) between the voltages applied to the common electrode 14 and the pixel electrode 15. A well-known technique can be applied to the driving method of the pixels 13.

[0021] The color particles 16 are pigments. The color particles 16 constitute a part of an image displayed on the display panel 10. The color particles 16 move when a voltage is applied to the pixels 13. In the present embodiment, "move" includes moving and rotating. In the present embodiment, the color particles 16 are electrophoretic particles. Specifically, the color particles 16 move in a solvent in accordance with the voltage applied between the common electrode 14 and the pixel electrode 15.

[0022] For example, when a positive potential is applied to the pixel electrode 15, the negatively charged color particles 16 are attracted to the pixel electrode 15, and the positively charged color particles 16 are attracted to the common electrode 14. In contrast, when a negative potential is applied to the pixel electrode 15, the negatively charged color particles 16 are attracted to the common electrode 14, and the positively charged color particles 16 are attracted to the pixel electrode 15. As described above, the electronic paper 100 displays an image by controlling the voltages applied to the common electrode 14 and the pixel electrode 15 to move the color particles 16.

[0023] The color particles 16 are, for example, organic or inorganic particles. In this embodiment, the color particles 16 include, for example, black particles 16a containing black pigment, white particles 16b containing white pigment, and colored particles 16c containing colored pigments. The colored particles 16c may also be red particles containing red pigment, blue particles containing blue pigment, green particles containing green pigment, yellow particles containing yellow pigment, etc. Furthermore, there may be multiple colored particles 16c. In this embodiment, for the sake of explanation, three types of color particles 16 (black particles 16a, white particles 16b, and colored particles 16c) will be described as shown in Figure 2.

[0024] Of the three types of colored particles 16, two types have strong charge intensity and opposite charge polarity (reverse polarity), while the remaining type of colored particle 16 has a weaker charge intensity than the other two. For example, black particle 16a is positively charged with a strong charge intensity, white particle 16b is negatively charged with a strong charge intensity, and colored particle 16c is charged with a lower charge intensity than black particle 16a and white particle 16b. In other words, the charge levels of black particle 16a and white particle 16b are higher than the charge levels of colored particle 16c. Furthermore, colored particle 16c has the same charge polarity as either black particle 16a or white particle 16b. Note that colored particle 16c may be larger in size than black particle 16a and white particle 16b.

[0025] Here, the high drive voltages (Vh1, Vh2) are defined as sufficient drive voltages to drive the pixel 13 from one extreme color state to another extreme color state. For example, if the black particles 16a and white particles 16b are particles charged with a strong charge intensity, the high drive voltages (Vh1, Vh2) refer to sufficient drive voltages to drive the pixel 13 from the color state of the black particles 16a (black) to the color state of the white particles 16b (white), or from the color state of the white particles 16b (white) to the color state of the black particles 16a (black). For example, drive voltage Vh1, when applied over an appropriate time period, refers to a drive voltage sufficient to drive the pixel 13 from the color state of the first type of color particle to the color state of the second type of color particle, and drive voltage Vh2, when applied over an appropriate time period, refers to a drive voltage sufficient to drive the pixel 13 from the color state of the second type of color particle to the color state of the first type of color particle.

[0026] Figure 3 shows a specific example of how the image is displayed. Here, the black particles 16a are positively charged with a strong charge intensity, the white particles 16b are negatively charged with a strong charge intensity, and the colored particles 16c are positively charged with a weak charge intensity. Furthermore, the black particles 16a and white particles 16b are smaller in size than the colored particles 16c and can move faster than the colored particles 16c under a certain driving voltage.

[0027] In Figure 3, pixel 13a shows the state when a driving voltage of +15V (Vh1) is applied. In this case, the white particles 16b move towards the pixel electrode 15, while the black particles 16a and colored particles 16c move towards the common electrode 14. The colored particles 16c move towards the common electrode 14 on the viewing side, but because their charge intensity is weak and their size is large, their movement speed is slower than that of the black particles 16a. As a result, a black image is seen on the viewing side.

[0028] In Figure 3, pixel 13b shows the state when a drive voltage of -15V (Vh2) is applied. In this case, the white particles 16b move towards the common electrode 14, and the black particles 16a and colored particles 16c move towards the pixel electrode 15. As a result, a white image is seen on the viewing side.

[0029] The drive voltages Vh1 and Vh2 have opposite polarities and either the same or different amplitudes. In the example shown in Figure 3, drive voltage Vh1 is positive polarity (same polarity as black particle 16a), and drive voltage Vh2 is negative polarity (same polarity as white particle 16b).

[0030] Pixel 13c in Figure 3 shows the state when a drive voltage of +5V (Vh3) is applied. In this case, the colored particle 16c moves towards the common electrode 14. The black particle 16a and the white particle 16b approach each other and become coupled due to the opposite polarity of the charges they each carry, but because a sufficient drive voltage is not applied to release (separate) the coupling state, they remain in an intermediate position. As a result, a colored image can be seen on the viewing side.

[0031] Here, when displaying a colored image, in order to reduce color bleeding and afterimages, an inversion operation is performed in which strong drive voltages (Vh1 and Vh2) are applied in a short period of inversion before applying the drive voltage of the colored image (e.g., +5V (Vh3)). By performing the inversion operation, the black particles 16a and white particles 16b become coupled to each other, thereby reducing color bleeding and afterimages.

[0032] Figure 4 shows an example of switching from a white image to a colored image. In this case, the drive voltage Vh2, which displays the white image, is first switched to drive voltage Vh1 to display a black image (period t1). Then, during period t2, an inversion operation is performed in which drive voltages Vh1 and Vh2 are reversed at short intervals. After the inversion operation in period t2 is completed, drive voltage Vh3 is applied. Note that drive voltage Vh3 may be a negative polarity voltage.

[0033] Figure 5 shows an example of switching from a black image to a colored image. In this case, the drive voltage Vh1, which displays the black image, is first switched to drive voltage Vh2 to display a white image (period t1). Then, during period t2, an inversion operation is performed in which drive voltages Vh1 and Vh2 are reversed at short intervals. After the inversion operation in period t2 is completed, drive voltage Vh3 is applied. Note that drive voltage Vh3 may be a negative polarity voltage.

[0034] By performing the aforementioned inversion operation, during period t2, the black particles 16a and white particles 16b are reliably bound together, and only the colored particles 16c are easily moved to the common electrode 14 side (display surface side), making it possible to display a clear colored image without color bleeding or afterimages. Furthermore, when switching from the first colored image to the second colored image, the display quality of the colored image can be improved by performing the same inversion operation.

[0035] While the aforementioned inversion operation can improve display quality, it also leads to increased power consumption. Therefore, this embodiment provides a configuration that can reduce power consumption while preventing a decrease in display quality. This configuration will be described below.

[0036] Figure 6 is a block diagram showing the configuration of the electronic paper 100. In addition to the display panel 10 and control device 20 described above, the electronic paper 100 includes a communication unit 3 and a battery 4. The electronic paper 100 may further include operation buttons that accept user input. The electronic paper 100 may also include a touch panel on the surface of the display panel 10 that accepts user input.

[0037] Communication unit 3 is, for example, an interface device for wireless communication. Communication unit 3 is, for example, a network interface controller. Communication unit 3 communicates with a personal computer, etc., via a communication network such as the Internet and a public telephone network. Communication unit 3 can receive instruction signals from an instruction terminal (not shown) of a personal computer, etc. Communication unit 3 may also be able to send and receive signals to and from an instruction terminal (not shown). Furthermore, communication unit 3 may be, for example, an interface device for wired communication.

[0038] Battery 4 is a rechargeable battery that charges power and supplies the charged power to the display panel 10. Battery 4 is composed of, for example, a solar cell. In other words, the electronic paper 100 is powered by the power of battery 4.

[0039] The control device 20 includes a control unit 21 and a storage unit 22. The control unit 21 has a processor. The control unit 21 has, for example, a central processing unit (CPU). The control unit 21 may also have a general-purpose computing unit.

[0040] The storage unit 22 stores data and computer programs. The data includes, for example, image data relating to display images to be displayed on the display panel 10.

[0041] The storage unit 22 includes a main memory and an auxiliary storage device. The main memory is, for example, a semiconductor memory. The auxiliary storage device is, for example, a semiconductor memory and / or a hard disk drive. The storage unit 22 may also include removable media. The control unit 21 executes the computer program stored in the storage unit 22 to perform the image display processing (see Figure 9), which will be described later.

[0042] The control unit 21 includes control devices such as a CPU, ROM, and RAM. The CPU is a processor that performs various arithmetic operations. The ROM pre-stores control programs such as a BIOS and OS for the CPU to perform various operations. The RAM stores various information and is used as a temporary storage memory (work area) for the various operations performed by the CPU. The control unit 21 controls the control device 20 by executing various control programs pre-stored in the ROM or storage unit 22 using the CPU.

[0043] Specifically, the control unit 21 includes various processing units such as a display processing unit 211, a monitoring processing unit 212, and a switching processing unit 213. The control unit 21 functions as these various processing units by executing various processes according to the control program using the CPU. Some or all of the processing units included in the control unit 21 may be composed of electronic circuits. The control program may be a program that causes multiple processors to function as these various processing units.

[0044] The display processing unit 211 displays an image on the display panel 10. Specifically, the display processing unit 211 displays an image by applying voltage to the common electrode 14 and the pixel electrode 15 using power supplied from the battery 4, thereby moving the color particles 16. The display processing unit 211 also displays an image on the display panel 10 by applying a voltage corresponding to the display color of each pixel 13 to the pixel electrode 15. For example, the display processing unit 211 applies drive voltages Vh1 and Vh2 to the pixel electrode 15 to display a two-color image of black and white using black particles 16a and white particles 16b (see pixels 13a and 13b in Figure 3). The display processing unit 211 also applies drive voltages Vh1, Vh2, and Vh3 to the pixel electrode 15 to display a multi-color image of three or more colors, including black, white, and colored images, using black particles 16a, white particles 16b, and colored particles 16c. In other words, the display processing unit 211 includes a two-color display mode for displaying images in two colors and a multi-color display mode for displaying images in three or more colors.

[0045] The monitoring processing unit 212 monitors the remaining amount of power (charge level) stored in the battery 4. The monitoring processing unit 212 also determines whether the charge level has fallen below a preset threshold.

[0046] The switching processing unit 213 switches the image display mode between a two-color display mode, which displays a two-color image using two types of color particles, and a multi-color display mode, which displays an image with three or more colors using three or more types of color particles. In this embodiment, the switching processing unit 213 switches between a two-color display mode, which displays a two-color image of a black image and a white image using black particles 16a and white particles 16b, and a multi-color display mode, which displays an image with three or more colors of a black image, a white image, and a colored image using black particles 16a, white particles 16b, and colored particles 16c. Specifically, the switching processing unit 213 switches the display mode to the two-color display mode or the multi-color display mode based on the remaining charge of the battery 4. For example, the switching processing unit 213 sets the display mode to the multi-color display mode when the remaining charge of the battery 4 is above a threshold, and sets the display mode to the two-color display mode when the remaining charge of the battery 4 is below a threshold.

[0047] For example, when the remaining charge of the battery 4 is above a threshold and the display mode is set to multi-color display mode, the display processing unit 211 performs an inversion operation to reverse the polarity of the drive voltage applied to the pixel electrode 15 at a predetermined period (period t2 in Figures 4 and 5) and then applies a drive voltage (Vh3) corresponding to the display color (e.g., color) of the pixel 13 to the pixel electrode 15.

[0048] In contrast, when the remaining charge of the battery 4 falls below a threshold and the display mode is switched to two-color display mode, the display processing unit 211 omits the inversion operation, or performs the inversion operation for a period shorter than the predetermined period (period t2), and then applies a drive voltage (Vh1 or Vh2) corresponding to the display color (e.g., white or black) of the pixel 13 to the pixel electrode 15. For example, as shown in Figure 7, in a pixel 13 that switches from a colored image to a black image, the display processing unit 211 omits the inversion operation and switches from drive voltage Vh3 to drive voltage Vh1 to display a black image. Also, as shown in Figure 8, for example, in a pixel 13 that switches from a colored image to a white image, the display processing unit 211 omits the inversion operation and switches from drive voltage Vh3 to drive voltage Vh2 to display a white image.

[0049] Thus, in the two-color display mode, the display processing unit 211 displays the first color by applying a first voltage, which is a negative voltage value, to the first electrode of the first pixel 13, and displays the second color by applying a second voltage, which is a positive voltage value, to the first electrode of the second pixel 13. In contrast, in the multi-color display mode, the display processing unit 211 applies predetermined voltages (for example, the first voltage and the second voltage) to the first electrode of each pixel 13 with their polarity reversed at a predetermined period during the inversion operation. Subsequently, it displays the first color by applying a first voltage, which is a negative voltage value, to the first electrode of the first pixel 13, displays the second color by applying a second voltage, which is a positive voltage value, to the first electrode of the second pixel 13, and displays the third color by applying a third voltage, which is a voltage value between the first voltage and the second voltage, to the first electrode of the third pixel 13. The driving voltage applied in the inversion operation may be a voltage greater than or equal to the absolute values ​​of the first voltage and the second voltage (the fourth voltage of this disclosure).

[0050] Furthermore, the display processing unit 211 performs the inversion operation when there is sufficient charge remaining in the battery 4, and omits the inversion operation when the charge remaining in the battery 4 decreases. Also, in the two-color display mode, for example, a two-color image can be displayed using drive voltages Vh1 and Vh2, and since there is no need to perform the inversion operation, the inversion operation is omitted. This reduces power consumption.

[0051] [Image display processing] The following describes an example of the image display processing procedure performed on the electronic paper 100, with reference to Figure 9.

[0052] This disclosure can be understood as a disclosure of an image display method (display method of this disclosure) that performs one or more steps included in the image display process. Furthermore, one or more steps included in the image display process described herein may be omitted or divided as appropriate. In addition, the execution order of each step in the image display process may differ to the extent that similar effects are produced. Furthermore, although this description uses the case in which the control unit 21 (one processor) of the control device 20 executes each step in the image display process as an example, in other embodiments, multiple processors may distribute and execute each step in the image display process.

[0053] <Step S1> In step S1, the control unit 21 acquires an input image. For example, the control unit 21 acquires image data output from an external server via the communication unit 3.

[0054] <Step S2> In step S2, the control unit 21 determines whether the input image is a two-color image. Specifically, the control unit 21 determines whether the image is a two-color image that can be displayed by a single color particle 16 using high-voltage drive voltages (Vh1, Vh2) and is included in the color particles 16 that make up the display panel 10. For example, if the display panel 10 is composed of three color particles 16: black particles 16a, white particles 16b, and colored particles 16c of a specific color, the control unit 21 determines whether the input image is a two-color image consisting of a black image (black pixels) displayed by the black particle 16a when a drive voltage Vh1 (+15V) is applied, and a white image (white pixels) displayed by the white particle 16b when a drive voltage Vh2 (-15V) is applied. If the control unit 21 determines that the input image is a two-color image (e.g., a black and white image) (S2: Yes), it proceeds to step S4.

[0055] In contrast, if the input image is a colored image (for example, a multicolor image such as a color image) displayed by colored particles 16c with a low driving voltage (Vh3), the control unit 21 determines that the input image is not a two-color image (it is a multicolor image) (S2: No) and proceeds to step S3.

[0056] <Step S3> In step S3, the control unit 21 displays the image in multicolor display mode. Specifically, before displaying the input image, the control unit 21 performs an inversion operation for a predetermined period in which it applies strong drive voltages (Vh1 and Vh2) (the fourth voltage of this disclosure) to the pixel electrode 15 while inverting them at short intervals, and then applies a drive voltage (Vh3) corresponding to the display color of the input image to the pixel electrode 15. For example, as shown in Figures 4 and 5, during period t2, the control unit 21 applies drive voltages Vh1 and Vh2 to the pixel electrode 15 while inverting them at short intervals, and then applies a drive voltage Vh3 corresponding to the display color (color) of the input image.

[0057] <Step S4> In step S4, the control unit 21 obtains the remaining charge of the battery 4 and determines whether the remaining charge has fallen below a threshold. If the remaining charge is above the threshold (S4: No), the control unit 21 returns to step S1, and if the remaining charge falls below the threshold (S4: Yes), it proceeds to step S5. As long as the remaining charge is above the threshold, the control unit 21 performs the inversion operation in multicolor display mode to display a multicolor image if the input image is a multicolor image.

[0058] <Step S5> In step S5, the control unit 21 switches the display mode to two-color display mode. That is, if the remaining charge of the battery 4 decreases to below a threshold while displaying an image in multi-color display mode (S4: Yes), the control unit 21 switches the display mode from multi-color display mode to two-color display mode.

[0059] <Step S6> In step S6, the control unit 21 displays the image in two-color display mode. Specifically, if the input image is a two-color image (S2: Yes), the control unit 21 applies drive voltages Vh1 and Vh2 to the pixel electrodes 15 to display the two-color image. For example, for black pixels in the input image, the control unit 21 applies a drive voltage Vh1 of +15V to the pixel electrode 15, as shown in pixel 13a of Figure 3, and for white pixels in the input image, it applies a drive voltage Vh2 of -15V to the pixel electrode 15, as shown in pixel 13b of Figure 3. Furthermore, when switching a black image to a white image, or vice versa, the control unit 21 applies the drive voltage Vh1 or Vh2 without performing the inversion operation.

[0060] Furthermore, when the input image is a multicolor image (S2: No), or when the remaining charge of the battery 4 falls below a threshold (S4: Yes), the control unit 21 switches to a two-color display mode and applies drive voltages Vh1 and Vh2 to the pixel electrodes 15 to display the two-color image. For example, when the control unit 21 displays the colored pixels of the input image as black pixels, it applies a drive voltage of +15V Vh1 to the pixel electrodes 15 as shown in Figure 7, and when the colored pixels of the input image are displayed as white pixels, it applies a drive voltage of -15V Vh2 to the pixel electrodes 15 as shown in Figure 8. Also, when the control unit 21 switches from drive voltage Vh3 to drive voltage Vh1 or drive voltage Vh2, it omits the inversion operation (see Figures 4 and 5).

[0061] In another embodiment, the control unit 21 may perform the inversion operation for a period shorter than the period (period t2) during which the inversion operation is performed when the remaining charge of the battery 4 is equal to or greater than a threshold when switching from the drive voltage Vh3 to the drive voltage Vh1 or the drive voltage Vh2.

[0062] In another embodiment, the control unit 21 may perform the reversal operation for a period shorter than period t2 when the remaining charge of the battery 4 falls below a first threshold, and may omit the reversal operation when the remaining charge of the battery 4 falls below a second threshold which is lower than the first threshold.

[0063] After step S6, the control unit 21 returns the process to step S1. In this way, when displaying a two-color image, the control unit 21 displays the image in two-color display mode without performing the inversion operation, and when displaying a multi-color image, it performs the inversion operation to display the image in multi-color display mode, and when the remaining charge of the battery 4 falls below a threshold in multi-color display mode, it switches to two-color display mode and displays the image.

[0064] Furthermore, in two-color display mode, if the remaining charge of battery 4 falls below a threshold, a notification prompting the user to perform a charge operation may be displayed.

[0065] As described above, the electronic paper 100 according to this embodiment includes a display panel 10 on which a plurality of pixels 13 are arranged, each containing a first electrode on the display surface side (e.g., a common electrode 14), a second electrode on the non-display surface side (e.g., a pixel electrode 15), and three or more different colored particles 16 that are placed between the first electrode and the second electrode. The electronic paper 100 also includes a display processing unit 211 that displays an image on the display panel 10 by applying a voltage corresponding to the display color of each pixel 13 to the first electrode, and a switching processing unit 213 that switches between a two-color display mode that displays two colors using two types of colored particles 16 and a multi-color display mode that displays three or more colors using three or more types of colored particles 16. In the multi-color display mode, the display processing unit 211 performs an inversion operation for a predetermined period of time, inverting the polarity of the voltage applied to the first electrode at a predetermined interval, and then applies a voltage corresponding to the display color of the pixel 13 to the first electrode. Furthermore, in two-color display mode, the display processing unit 211 omits the inversion operation, or performs the inversion operation for a shorter period than the predetermined period, and then applies a voltage corresponding to the display color of the pixel 13 to the first electrode.

[0066] For example, the switching processing unit 213 switches to two-color display mode when the battery level of the display panel 10 falls below a threshold. The switching processing unit 213 also switches between two-color display mode and multi-color display mode based on the attribute information (color information) of the image to be displayed. For example, the switching processing unit 213 switches to two-color display mode if the image to be displayed is a two-color image, and switches to multi-color display mode if the image to be displayed is a multi-color image.

[0067] According to the above configuration, the inversion operation can be performed in multi-color display mode, and the inversion operation can be omitted or suppressed in two-color display mode. As a result, power consumption can be reduced without degrading the display quality in two-color display mode while maintaining the display quality in multi-color display mode.

[0068] In another embodiment of the present invention, the switching processing unit 213 may switch between a two-color display mode and a multi-color display mode in response to a user's switching operation. For example, the user may set the display to multi-color display mode when they want to display a multi-color input image in high quality, and set it to two-color display mode when they are not concerned with the quality of the multi-color input image. Alternatively, the user may check the remaining charge of the battery 4 and set it to multi-color display mode when the remaining charge is high, and set it to two-color display mode when the remaining charge is low. The user may perform the switching operation on the display panel 10. The switching processing unit 213 switches to the display mode in response to the user's switching operation, and the display processing unit 211 displays the image in the display mode selected by the user.

[0069] In another embodiment of the present invention, the control unit 21 may be set to multicolor display mode as the default. In this case, the display processing unit 211 will, under normal conditions, display the image in multicolor display mode regardless of the color information (attributes) of the input image. That is, the display processing unit 211 will perform the inversion operation and display the image whether the input image is a two-color image or a multicolor image. In this case, when the remaining charge of the battery 4 falls below a threshold, the switching processing unit 213 switches to two-color display mode. After that, the display processing unit 211 displays the image in two-color display mode, and when the remaining charge is above the threshold or fully charged, it switches to the default multicolor display mode and displays the image.

[0070] In the embodiments described above, the display system of the present disclosure is configured with electronic paper 100, but the display system of the present disclosure may be configured with a control device 20 alone. That is, the display system may be configured to include a display processing unit 211, a monitoring processing unit 212, and a switching processing unit 213. Also, in the embodiments described above, the control device 20 is built into the housing 1 of the electronic paper 100 (see Figure 1), but in other embodiments, the control device 20 may be located outside the housing 1. For example, the control device 20 may be located outside the housing 1 and connected to the display panel 10 wirelessly via a communication network (such as the Internet).

[0071] The control unit 21 of the control device 20 controls the entire electronic paper 100. The control unit 21 realizes various functions by reading and executing various programs stored in the memory unit 22 (for example, storage or ROM). The control unit 21 may be realized by one or more control devices / arithmetic units (CPU (Central Processing Unit), SoC (System on a Chip)). The control unit 21 may also be composed of one or more control circuits (electronic circuits).

[0072] [Note on disclosure] The following is an overview of the disclosures extracted from the embodiments described above. Note that each configuration and processing function described below can be selected and combined as desired.

[0073] <Note 1> A display panel having multiple pixels arranged, each containing a first electrode on the display side, a second electrode on the non-display side, and three or more color particles of different colors that are sandwiched between the first and second electrodes, A display processing unit that displays an image on the display panel by applying a voltage corresponding to the display color of each pixel to the first electrode, A switching processing unit that switches between a two-color display mode that displays two colors using two types of color particles and a multi-color display mode that displays three or more colors using three or more types of color particles, Equipped with, In the multi-color display mode, the display processing unit performs an inversion operation for a predetermined period of time, inverting the polarity of the voltage applied to the first electrode at predetermined intervals, and then applies a voltage corresponding to the display color of the pixel to the first electrode. In the case of the two-color display mode, the display processing unit omits the inversion operation, or performs the inversion operation for a period shorter than the predetermined period, and then applies a voltage corresponding to the display color of the pixel to the first electrode. Display device.

[0074] <Note 2> The switching processing unit switches to the two-color display mode when the battery level of the display panel falls below a threshold. The display device described in Appendix 1.

[0075] <Note 3> The switching processing unit switches between the two-color display mode and the multi-color display mode in response to a user's switching operation. The display device described in Appendix 1 or 2.

[0076] <Note 4> The switching processing unit switches between the two-color display mode and the multi-color display mode based on the attribute information of the image to be displayed. A display device as described in any of the appendices 1 to 3.

[0077] <Note 5> The three or more color particles mentioned above include a positively charged first color particle and a negatively charged second color particle. The plurality of pixels include a first pixel that displays a first color and a second pixel that displays a second color. The display processing unit displays the first color by applying a first voltage, which is a negative voltage value, to the first electrode of the first pixel, and displays the second color by applying a second voltage, which is a positive voltage value, to the first electrode of the second pixel. A display device as described in any of the appendices 1 to 4.

[0078] <Note 6> The three or more color particles include a positively charged first color particle, a negatively charged second color particle, and a positively or negatively charged third color particle. The plurality of pixels include a first pixel that displays a first color, a second pixel that displays a second color, and a third pixel that displays a third color. The display processing unit, in the inversion operation, applies the fourth voltage to the first electrode of each pixel after inverting its polarity at a predetermined period, and thereafter displays the first color by applying a first voltage, which is a negative voltage value, to the first electrode of the first pixel; displays the second color by applying a second voltage, which is a positive voltage value, to the first electrode of the second pixel; and displays the third color by applying a third voltage, which is a voltage value between the first voltage and the second voltage, to the first electrode of the third pixel. A display device as described in any of the appendices 1 to 4.

[0079] <Note 7> The absolute value of the fourth voltage is greater than or equal to the absolute values ​​of the first voltage and the second voltage. The display device described in Appendix 6.

[0080] <Note 8> A display method for displaying an image in a display panel in which a plurality of pixels are arranged, each including a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more color particles of different colors that are sandwiched between the first electrode and the second electrode, wherein a voltage corresponding to the display color of each pixel is applied to the first electrode, The system can switch between a two-color display mode, which displays two colors using two types of color particles, and a multi-color display mode, which displays three or more colors using three or more types of color particles. In the multi-color display mode, after performing an inversion operation to reverse the polarity of the voltage applied to the first electrode at a predetermined period, a voltage corresponding to the display color of the pixel is applied to the first electrode. In the case of the two-color display mode, the inversion operation is omitted, or the inversion operation is performed for a period shorter than the predetermined period, and then a voltage corresponding to the display color of the pixel is applied to the first electrode. A display method executed by one or more processors.

[0081] <Note 9> A display program for displaying an image in a display panel in which a plurality of pixels are arranged, each containing a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more color particles of different colors that are sandwiched between the first electrode and the second electrode, wherein the voltage corresponding to the display color of each pixel is applied to the first electrode, The system can switch between a two-color display mode, which displays two colors using two types of color particles, and a multi-color display mode, which displays three or more colors using three or more types of color particles. In the multi-color display mode, after performing an inversion operation to reverse the polarity of the voltage applied to the first electrode at a predetermined period, a voltage corresponding to the display color of the pixel is applied to the first electrode. In the case of the two-color display mode, the inversion operation is omitted, or the inversion operation is performed for a period shorter than the predetermined period, and then a voltage corresponding to the display color of the pixel is applied to the first electrode. A display program for causing one or more processors to execute, or a non-temporary computer-readable recording medium on which the display program is recorded. [Explanation of Symbols]

[0082] 100: Electronic paper 10: Display Panel 4: Battery 11: First board 12: Second board 13: Pixels 14: Common electrode 15: Pixel electrode 16: Color particles 16a: black particles 16b: White particles 16c: Colored particles 20: Control device 21: Control Unit 22: Storage section 211: Display Processing Unit 212: Monitoring Processing Unit 213: Switching Processing Unit Vh1: Drive voltage Vh2: Drive voltage Vh3: Drive voltage

Claims

1. A display panel having multiple pixels arranged, each containing a first electrode on the display side, a second electrode on the non-display side, and three or more color particles of different colors that are sandwiched between the first and second electrodes, A display processing unit that displays an image on the display panel by applying a voltage corresponding to the display color of each pixel to the first electrode, A switching processing unit that switches between a two-color display mode that displays two colors using two types of color particles and a multi-color display mode that displays three or more colors using three or more types of color particles, Equipped with, In the multi-color display mode, the display processing unit performs an inversion operation for a predetermined period of time, inverting the polarity of the voltage applied to the first electrode at predetermined intervals, and then applies a voltage corresponding to the display color of the pixel to the first electrode. In the case of the two-color display mode, the display processing unit omits the inversion operation, or performs the inversion operation for a period shorter than the predetermined period, and then applies a voltage corresponding to the display color of the pixel to the first electrode. Display device.

2. The switching processing unit switches to the two-color display mode when the battery level of the display panel falls below a threshold. The display device according to claim 1.

3. The switching processing unit switches between the two-color display mode and the multi-color display mode in response to the user's switching operation. The display device according to claim 1.

4. The switching processing unit switches between the two-color display mode and the multi-color display mode based on the attribute information of the image to be displayed. The display device according to claim 1.

5. The three or more color particles include a positively charged first color particle and a negatively charged second color particle. The plurality of pixels include a first pixel that displays a first color and a second pixel that displays a second color. The display processing unit displays the first color by applying a first voltage, which is a negative voltage value, to the first electrode of the first pixel, and displays the second color by applying a second voltage, which is a positive voltage value, to the first electrode of the second pixel. The display device according to claim 1.

6. The three or more color particles include a positively charged first color particle, a negatively charged second color particle, and a positively or negatively charged third color particle. The plurality of pixels include a first pixel that displays a first color, a second pixel that displays a second color, and a third pixel that displays a third color. The display processing unit, in the inversion operation, inverts the polarity of the fourth voltage at a predetermined period and applies it to the first electrode of each pixel, and thereafter displays the first color by applying a first voltage, which is a negative voltage value, to the first electrode of the first pixel, displays the second color by applying a second voltage, which is a positive voltage value, to the first electrode of the second pixel, and displays the third color by applying a third voltage, which is a voltage value between the first voltage and the second voltage, to the first electrode of the third pixel. The display device according to claim 1.

7. The absolute value of the fourth voltage is greater than or equal to the absolute values ​​of the first voltage and the second voltage. The display device according to claim 6.

8. A display method for displaying an image in a display panel in which a plurality of pixels are arranged, each containing a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more color particles of different colors that are sandwiched between the first electrode and the second electrode, wherein a voltage corresponding to the display color of each pixel is applied to the first electrode, The system can switch between a two-color display mode, which displays two colors using two types of color particles, and a multi-color display mode, which displays three or more colors using three or more types of color particles. In the multi-color display mode, after performing an inversion operation to reverse the polarity of the voltage applied to the first electrode at a predetermined period, a voltage corresponding to the display color of the pixel is applied to the first electrode. In the case of the two-color display mode, the inversion operation is omitted, or the inversion operation is performed for a period shorter than the predetermined period, and then a voltage corresponding to the display color of the pixel is applied to the first electrode. A display method executed by one or more processors.

9. A display program for displaying an image in a display panel in which a plurality of pixels are arranged, each containing a first electrode on the display surface side, a second electrode on the non-display surface side, and three or more color particles of different colors that are sandwiched between the first electrode and the second electrode, wherein the program applies a voltage corresponding to the display color of each pixel to the first electrode, The system can switch between a two-color display mode, which displays two colors using two types of color particles, and a multi-color display mode, which displays three or more colors using three or more types of color particles. In the multi-color display mode, after performing an inversion operation to reverse the polarity of the voltage applied to the first electrode at a predetermined period, a voltage corresponding to the display color of the pixel is applied to the first electrode. In the case of the two-color display mode, the inversion operation is omitted, or the inversion operation is performed for a period shorter than the predetermined period, and then a voltage corresponding to the display color of the pixel is applied to the first electrode. A display program that is executed on one or more processors.

Images