Electronic paper and control method of electronic paper

Abstract

To provide electronic paper capable of maintaining display quality even when an installation angle is different from usual for a long period of time, and a control method of the electronic paper.SOLUTION: Electronic paper 100B includes a display panel 10, an installation angle detection part 5, a display control part 211, and a refreshing timing determination part 212B. The display panel 10 includes color particles 132 moving by application of voltage. The installation angle detection part 5 detects an installation angle of the display panel 10. The display control part 211 controls writing operation of writing an image in the display panel 10 by the application of the voltage to the color particles 132. The refreshing timing determination part 212B determines refreshing timing on the basis of a detection angle θ of the installation angle detection part 5. The display control part 211 executes refreshing operation at the determined refreshing timing.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to electronic paper and a method for controlling electronic paper. [Background technology]

[0002] Conventionally, electronic paper has been known as a display device that can be rewritten many times and has low power consumption (see, for example, Patent Document 1). Patent Document 1 describes the electronic paper. In an electrophoretic display device in which this electronic paper is provided in a display area, when an image is displayed and maintained on the display unit, in order to prevent deterioration of contrast over time, the device transitions to an image maintenance step, and after a predetermined time has elapsed, a refresh step is executed in which the image is displayed again. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-229832 Summary of the Invention [Problem to be solved by the invention]

[0004] However, while conventional electronic paper can maintain its display content without a power source, the display quality gradually deteriorates. For this reason, there is a demand for electronic paper that can maintain its display quality even after a long period of time, especially when installed at an unusual angle.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide electronic paper and a method for controlling electronic paper that can maintain display quality even after a long period of time has passed at an installation angle that is different from normal. [Means for solving the problem]

[0006] An electronic paper according to a first aspect of the present disclosure includes a display panel, an installation angle detection unit, a display control unit, and a refresh timing determination unit. The display panel includes color particles that move when a voltage is applied. The installation angle detection unit detects the installation angle of the display panel. The display control unit controls a write operation that writes an image on the display panel by applying a voltage to the color particles. The refresh timing determination unit determines a refresh timing for executing a refresh operation that is an operation of performing the write operation again after the previous write operation. The refresh timing determination unit determines the refresh timing based on the angle detected by the installation angle detection unit. The display control unit executes the refresh operation at the determined refresh timing.

[0007] A second aspect of the present disclosure provides a method for controlling electronic paper, which includes a display panel including color particles that move when a voltage is applied to the display panel. The method includes the steps of detecting an installation angle of the display panel, applying a voltage to the color particles to write an image to the display panel, determining, based on the detected installation angle, a refresh timing for performing a refresh operation to perform the previous write operation again, and performing the refresh operation at the determined refresh timing. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide electronic paper and a method for controlling electronic paper that can maintain display quality even after a long period of time has passed at an installation angle that is different from normal. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view schematically illustrating the structure of electronic paper 100 according to a first embodiment of the present disclosure. [Figure 2] 2 is an enlarged view schematically showing the structure of a microcapsule 13 and its surroundings in electronic paper 100. FIG. [Figure 3] FIG. 1 is a block diagram showing the configuration of electronic paper 100. [Figure 4] 10 is a flowchart illustrating a control method for the electronic paper 100. [Figure 5] FIG. 10 is a block diagram showing a configuration of electronic paper 100A according to a modified example of the first embodiment of the present disclosure. [Figure 6] FIG. 10 is a block diagram showing a configuration of electronic paper 100B according to a second embodiment of the present disclosure. [Figure 7A] FIG. 10 is a left side view showing a first example of an installation angle of electronic paper 100B. [Figure 7B] FIG. 10 is a left side view showing a second example of the installation angle of electronic paper 100B. [Figure 7C] FIG. 10 is a left side view showing a third example of the installation angle of electronic paper 100B. [Figure 8A] 10A and 10B are a left side view and a front view showing a state in which the electronic paper 100B is placed with the display panel 10 lying on its side. [Figure 8B] 10A and 10B are a left side view and a front view showing a state in which the electronic paper 100B is installed with the display panel 10 rotated vertically. [Figure 9] 10 is a flowchart illustrating a method for controlling electronic paper 100B. [Figure 10] FIG. 10 is a block diagram showing a configuration of electronic paper 100C according to a modified example of the second embodiment of the present disclosure. [Figure 11] FIG. 10 is a block diagram showing a configuration of electronic paper 100D according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0011] First Embodiment 1.1 Structure of e-Paper 100 An electronic paper 100 according to a first embodiment of the present disclosure will be described with reference to Figures 1 to 4. Figure 1 is a cross-sectional view that schematically shows the structure of electronic paper 100 according to the first embodiment of the present disclosure.

[0012] 1, electronic paper 100 functions as a display device that displays images. Electronic paper 100 is used, for example, as an electronic shelf label, an electronic advertisement, an electronic book reader, or an electronic notebook. Note that electronic paper 100 may also be used as a device other than an electronic shelf label, an electronic advertisement, an electronic book reader, or an electronic notebook.

[0013] The electronic paper 100 includes a housing 1 and a display panel 10. The housing 1 houses the display panel 10. The housing 1 has an opening 1a on the front surface.

[0014] The display panel 10 displays an image. The display panel 10 is formed to be larger than the opening 1a of the housing 1 and is disposed so as to cover the opening 1a. The area of the display panel 10 corresponding to the opening 1a is a display area in which an image is viewed by a user.

[0015] The display panel 10 also includes a first substrate 11, a second substrate 12 disposed opposite the first substrate 11, a plurality of microcapsules 13, a first electrode 14, and a second electrode 15.

[0016] The first substrate 11 is formed of a transparent plate or sheet member such as glass or resin. An anti-reflection film may be formed on the outer surface of the first substrate 11 (the surface opposite to the second substrate 12), or the first substrate 11 may be subjected to a water-repellent treatment. The second substrate 12 is formed of a plate or sheet member such as glass or resin.

[0017] The microcapsules 13 are disposed between the first substrate 11 and the second substrate 12. The microcapsules 13 are spread, for example, in one layer between the first substrate 11 and the second substrate 12. The microcapsules 13 have a substantially spherical shape. The microcapsules 13 have a diameter, for example, of several tens of μm or more and several hundred μm or less.

[0018] 2 is an enlarged view schematically illustrating the structure around a microcapsule 13 of electronic paper 100. As shown in FIG. 2, the microcapsule 13 has a film 131, a plurality of color particles 132, and a dispersion liquid 133. The film 131 is, for example, transparent. The film 131 is, for example, a film made of a transparent resin. The material of the film 131 is not particularly limited, but may be, for example, a urethane resin, a melamine resin, or rubber.

[0019] The color particles 132 are pigments. The color particles 132 constitute part of an image displayed on the display panel 10. The color particles 132 move when a voltage is applied. In this embodiment, movement includes movement and rotation. In this embodiment, the color particles 132 are electrophoretic particles. Specifically, the color particles 132 move within the dispersion liquid 133 in response to a voltage applied between the first electrode 14 and the second electrode 15. As a result, a predetermined image is displayed on the display panel 10.

[0020] The color particles 132 are, for example, organic or inorganic particles. In this embodiment, the color particles 132 include, for example, black particles 132a as a black pigment and white particles 132b as a white pigment. The black particles 132a as a black pigment are not particularly limited, but include, for example, carbon black or titanium black. The white particles 132b as a white pigment are not particularly limited, but include, for example, titanium dioxide or antimony trioxide. The black particles 132a and the white particles 132b are examples of "color particles" in the present disclosure.

[0021] The black particles 132a are, for example, negatively charged. On the other hand, the white particles 132b are, for example, positively charged. That is, the black particles 132a and the white particles 132b are different in color and are charged with different polarities. Note that the black particles 132a may be positively charged and the white particles 132b may be negatively charged.

[0022] In this embodiment, as described above, the color particles 132 include a black pigment and a white pigment. However, the color particles 132 may include a pigment of another color instead of the black pigment and the white pigment. Furthermore, the color particles 132 may include a pigment of another color in addition to the black pigment and the white pigment. For example, a yellow pigment, a red pigment, a blue pigment, a white pigment, and / or a green pigment may be used as the pigment of another color.

[0023] The dispersion liquid 133 is, for example, transparent. The dispersion liquid 133 is an insulating liquid. The dispersion liquid 133 is not particularly limited, but may include, for example, water, an alcohol-based solvent, an ester, a ketone, an aliphatic hydrocarbon, an alicyclic hydrocarbon, an aromatic hydrocarbon, or an oil. In this embodiment, the dispersion liquid 133 includes, for example, an aliphatic hydrocarbon.

[0024] The first electrode 14 and the second electrode 15 are disposed opposite to each other with the microcapsules 13 sandwiched between them.

[0025] The first electrode 14 is disposed, for example, on the outer side (first substrate 11 side) of the microcapsules 13. The first electrode 14 may be formed, for example, on the first substrate 11. In this embodiment, the first electrode 14 is formed on the first substrate 11.

[0026] The first electrode 14 is formed of a light-transmitting conductive material. The first electrode 14 is not particularly limited, but is formed of, for example, ITO (Indium Tin Oxide). In this embodiment, the first electrode 14 is a common electrode. For example, one first electrode 14 is provided for a plurality of pixels (here, all pixels). For example, the first electrode 14 is grounded and has a ground potential.

[0027] The second electrode 15 is disposed, for example, on the inner side (second substrate 12 side) of the microcapsules 13. The second electrode 15 may be formed, for example, on the second substrate 12. In this embodiment, the second electrode 15 is formed on the second substrate 12.

[0028] The second electrode 15 is formed of, but is not particularly limited to, a metal material such as copper. In this embodiment, the second electrode 15 is a pixel electrode. The second electrode 15 is formed in a substantially rectangular shape in a plan view, and a plurality of second electrodes 15 are provided. The plurality of second electrodes 15 are arranged adjacent to each other with a predetermined gap therebetween.

[0029] For example, when a positive potential is applied to the second electrode 15a, the black particles 132a between the second electrode 15a and the first electrode 14 are attracted to the second electrode 15a. Also, the white particles 132b between the second electrode 15a and the first electrode 14 are attracted to the first electrode 14.

[0030] On the other hand, for example, when a negative potential is applied to the second electrode 15b, the black particles 132a between the second electrode 15b and the first electrode 14 are attracted to the first electrode 14. Also, the white particles 132b between the second electrode 15b and the first electrode 14 are attracted to the second electrode 15b.

[0031] As shown in FIG. 1, the electronic paper 100 further includes a temperature sensor 2 and a control device 20.

[0032] The temperature sensor 2 detects temperature. The temperature sensor 2 is disposed, for example, inside the housing 1, on the opposite side from the control device 20. In other words, the temperature sensor 2 is disposed at a predetermined distance from the control device 20. This makes it possible to prevent the temperature T detected by the temperature sensor 2 from increasing due to heat from the control device 20.

[0033] The temperature sensor 2 is provided, for example, to measure the temperature around the electronic paper 100. For example, a vent may be provided in a portion of the housing 1 facing the temperature detection element of the temperature sensor 2. The temperature detection element of the temperature sensor 2 may also be exposed to the outside of the housing 1. The temperature T detected by the temperature sensor 2 may also be corrected and used as the temperature around the electronic paper 100.

[0034] The temperature sensor 2 is not particularly limited, but may be, for example, a thermocouple, a thermistor, or an infrared sensor. The temperature sensor 2 transmits the detection result (detected temperature T) to the control device 20.

[0035] The control device 20 controls various operations of the electronic paper 100. The control device 20 controls the display panel 10. In this way, the electronic paper 100 displays a predetermined image.

[0036] 1.2 Functional configuration of electronic paper 100 Next, the configuration of the electronic paper 100 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing the configuration of the electronic paper 100.

[0037] 3, the electronic paper 100 includes a communication unit 3 in addition to the display panel 10, temperature sensor 2, and control device 20 described above. The electronic paper 100 may further include operation buttons that accept input operations by the user. The electronic paper 100 may also include a touch panel on the surface of the display panel 10 that accepts input operations by the user.

[0038] The communication unit 3 is, for example, an interface device for wireless communication. The communication unit 3 is, for example, a network interface controller. The communication unit 3 communicates with a personal computer or the like via a communication network such as the Internet or a public telephone network. The communication unit 3 is capable of receiving an instruction signal from an instruction terminal (not shown) such as a personal computer. The communication unit 3 may also be capable of transmitting and receiving signals to and from the instruction terminal (not shown). The communication unit 3 may also be, for example, an interface device for wired communication.

[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). Alternatively, the control unit 21 may have a general-purpose computer.

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

[0041] The storage unit 22 includes a main storage device and an auxiliary storage device. The main storage device 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 include removable media. The control unit 21 executes a computer program stored in the storage unit 22 to perform a write operation and a refresh operation, which will be described later.

[0042] 1.3 Details of the control unit 21 Next, a detailed description will be given of the control unit 21. The control unit 21 includes a display control unit 211, a refresh timing determination unit 212, and an evaluation value calculation unit 213.

[0043] The display control unit 211 controls the write operation and the refresh operation. The write operation is an operation of writing an image to the display panel 10. The refresh operation is an operation of performing a write operation again after the immediately preceding write operation.

[0044] The refresh timing determination unit 212 determines the refresh timing at which the refresh operation is executed.

[0045] The display control unit 211 executes a writing operation based on image data. The display control unit 211 executes the writing operation within a writable temperature range. The display control unit 211 executes the writing operation by applying a voltage to the color particles 132. Specifically, the display control unit 211 executes the writing operation by applying a writing voltage between the first electrode 14 and the second electrode 15. The writable temperature range is not particularly limited, but is, for example, 0°C or higher and 50°C or lower.

[0046] The refresh timing determination unit 212 determines the refresh timing based on the temperature T detected by the temperature sensor 2. The display control unit 211 executes a refresh operation at the determined refresh timing.

[0047] Therefore, the refresh timing is determined based on the temperature T detected by the temperature sensor 2. As a result, it is possible to suppress the deterioration of display quality caused by the temperature of the environment in which the display device is installed.

[0048] The refresh operation is an operation in which a second voltage V2 different from the first voltage V1, which is a voltage corresponding to the display gradation after the refresh operation, is applied, followed by the application of the first voltage V1. Therefore, before applying the first voltage V1, which is a voltage corresponding to the original display gradation, the second voltage V2 different from the first voltage V1 is applied once, and then the first voltage V1 is applied again. As a result, degradation of display quality is effectively suppressed.

[0049] The second voltage V2 may be, for example, a voltage corresponding to the maximum value of the display grayscale or a voltage corresponding to the minimum value of the display grayscale, but is not limited to these.

[0050] The display gray scale after the refresh operation is the same as the display gray scale before the refresh operation. Therefore, the same display gray scale as before the refresh operation is reproduced after the refresh operation. As a result, the display gray scale is maintained while deterioration of the display quality is appropriately suppressed.

[0051] The control unit 21 further includes an evaluation value calculation unit 213. The evaluation value calculation unit 213 calculates an evaluation value E1 based on the history of the detected temperature T. The refresh timing determination unit 212 determines the timing at which the evaluation value E1 satisfies a first condition as the refresh timing.

[0052] Therefore, the evaluation value E1 is calculated based on the history of the detected temperature T, and the timing at which the evaluation value E1 satisfies the first condition is determined as the refresh timing. As a result, it is possible to further suppress deterioration of display quality caused by the temperature history of the installation environment.

[0053] For example, the evaluation value calculation unit 213 may calculate an evaluation value E1 corresponding to the detected temperature T for each time period in the history of the detected temperature T. Here, the first condition is, for example, that the time-integrated value of the evaluation value E1 is equal to or greater than a preset time-integrated threshold value.

[0054] Therefore, an evaluation value E1 corresponding to the detected temperature T is calculated for each time in the history of the detected temperature T, and the timing at which the time-integrated value of the evaluation value E1 becomes equal to or greater than a preset time-integrated threshold is determined as the refresh timing. As a result, degradation of display quality can be accurately suppressed even after a long period of time has passed under high temperatures.

[0055] The evaluation value E1 may be set to "0" if the detected temperature T is up to the upper limit TU of the writable temperature range, or may be set to the excess temperature ΔT if the detected temperature T is equal to or greater than the upper limit TU. Excess temperature ΔT = detection temperature T - upper limit value TU Then, the evaluation value calculation unit 213 calculates and accumulates this evaluation value E1, for example, every hour. However, the calculation method of the evaluation value E1 and the time interval for accumulation are not limited to this example. For example, the relationship between the excess temperature ΔT and the evaluation value E1 may be determined in advance so that the evaluation value E1 increases stepwise according to the magnitude of the excess temperature ΔT. Alternatively, a quadratic function of the excess temperature ΔT (where ΔT 2 The coefficient of may be positive.

[0056] The display control unit 211 does not execute a write operation at a temperature higher than the writable temperature range.Furthermore, the display control unit 211 does not execute a refresh operation at a temperature higher than the writable temperature range.

[0057] The display control unit 211 does not execute a write operation at a temperature lower than the lower limit TL of the writable temperature range.Furthermore, the display control unit 211 does not execute a refresh operation at a temperature lower than the lower limit TL.

[0058] The write voltage is a voltage corresponding to the display gradation of the image after writing. For example, in a dynamic range of 16 gray levels of black and white, if the display gradation of a pixel in the display image after writing is, for example, 5, a voltage corresponding to the display gradation of 5 is applied to that pixel. In the write operation, a voltage corresponding to the display gradation of each pixel in the display image after writing is applied to each pixel. Note that if the display gradation of a pixel in the display image after writing is, for example, 15 (white), a positive maximum voltage (a voltage corresponding to a display gradation of 15) is applied to that pixel. Also, if the display gradation of a pixel in the display image after writing is, for example, 0 (black), a negative maximum voltage (a voltage corresponding to a display gradation of 0) is applied to that pixel.

[0059] 1.4 Control method of electronic paper 100 Next, a control method for electronic paper 100 according to this embodiment will be described with reference to FIG. 4. FIG. 4 is a flowchart illustrating the control method for electronic paper 100. The control method for electronic paper 100 includes steps S1 to S5. Step S2 is an example of a "step of detecting temperature" in the present disclosure. Step S3 is an example of a "step of performing a write operation" in the present disclosure. Step S4 is an example of a "step of determining refresh timing" in the present disclosure. Step S5 is an example of a "step of performing a refresh operation" in the present disclosure.

[0060] 4, a control method after the electronic paper 100 receives an instruction to write an image from a user or an instruction terminal will be described. As described above, the electronic paper 100 includes a display panel 10 including color particles 132 that move when a voltage is applied. Note that a user's instruction to write is given, for example, by the user operating the electronic paper 100. Also, a command terminal's instruction to write is given, for example, by transmitting a write signal from the command terminal to the electronic paper 100 at a predetermined time.

[0061] 4, in step S1, the control unit 21 acquires image data relating to the display image after writing. Specifically, the control unit 21 acquires image data relating to the display image after writing from the storage unit 22. Note that the image data may be stored in the storage unit 22 in advance, or may be transmitted from the instruction terminal to the electronic paper 100.

[0062] In step S2, the temperature sensor 2 detects the temperature. Specifically, the temperature sensor 2 detects the temperature and transmits the detected temperature T to the control unit 21. The control unit 21 acquires the detected temperature T of the temperature sensor 2.

[0063] In step S3, the display control unit 211 executes a write operation to write an image to the display panel 10. The display control unit 211 applies a voltage to the color particles 132 to execute the write operation.

[0064] In step S4, the refresh timing determination unit 212 determines the refresh timing, which is the timing to execute a refresh operation to perform another write operation after the immediately preceding write operation, based on the temperature T detected in step S2.

[0065] In step S5, the display control unit 211 executes a refresh operation at the refresh timing determined in step S4.

[0066] Therefore, the refresh operation is performed based on the detected temperature T. As a result, it is possible to suppress the deterioration of display quality caused by the temperature of the environment in which the display device is installed.

[0067] 1.5 Modification of the first embodiment Next, a modified example of the first embodiment of the present disclosure will be described with reference to Fig. 5. Fig. 5 is a block diagram showing the configuration of electronic paper 100A according to the modified example of the first embodiment of the present disclosure. Differences from the first embodiment will be mainly described below.

[0068] 5, compared to the configuration of electronic paper 100 described above (see FIG. 3), electronic paper 100A includes a control device 20A instead of control device 20, and further includes a brightness detection unit 4. Control device 20A has a control unit 21A instead of control unit 21. Control unit 21A further includes a clock unit 214.

[0069] The display control unit 211 executes a refresh operation if the second condition is satisfied at the refresh timing. On the other hand, the display control unit 211 suspends execution of the refresh operation if the second condition is not satisfied at the refresh timing. Therefore, even if the refresh timing arrives, the refresh operation is not executed until the second condition is satisfied. As a result, it is possible to avoid a situation in which the display content of the display panel 10 becomes temporarily unreadable due to the refresh operation being executed at an inadvertent timing.

[0070] If the display control unit 211 has suspended the execution of the refresh operation, the display control unit 211 will execute the refresh operation when the second condition is satisfied. Therefore, the suspended refresh operation is executed. As a result, the display quality of the display panel 10 is restored.

[0071] The clock unit 214 keeps track of at least time t. Here, the second condition is that time t is within a preset time period. Therefore, even if a refresh operation needs to be performed, the refresh operation will not be performed until the preset time period arrives. As a result, the refresh operation can be performed by selecting a time period during which it will not be a problem even if the display content of the display panel 10 becomes temporarily unreadable.

[0072] Examples of the preset time period include late night and early morning when there is a high possibility that no one will be viewing the display panel 10, but the time period is not limited to these.

[0073] The brightness detector 4 detects the ambient brightness. The second condition is that the brightness detected by the brightness detector 4 is equal to or less than a preset brightness threshold. Therefore, even if a refresh operation needs to be performed, the refresh operation will not be performed while the ambient light is bright. As a result, the refresh operation can be performed by selecting a brightness situation where it is not a problem even if the display content of the display panel 10 becomes temporarily unreadable, such as a dark ambient situation.

[0074] The brightness threshold value may be, for example, a value corresponding to a brightness at which it is difficult to view the display panel 10, but is not limited to such a brightness.

[0075] Second Embodiment 2.1 Functional configuration of electronic paper 100B Next, a second embodiment of the present disclosure will be described with reference to FIGS. 6 to 9. FIG. 6 is a block diagram showing the configuration of electronic paper 100B according to the second embodiment of the present disclosure. FIGS. 7A to 7C are left side views illustrating the installation angles of electronic paper 100B. FIG. 8A is a left side view and a front view showing a state in which electronic paper 100B is installed with the display panel 10 in a horizontal position. FIG. 8B is a left side view and a front view showing a state in which electronic paper 100B is installed with the display panel 10 rotated to the vertical position. Differences from the first embodiment will be mainly described below.

[0076] 6, compared to the configuration of electronic paper 100 described above (see FIG. 5), electronic paper 100B has an installation angle detection unit 5 instead of temperature sensor 2, and a control device 20B instead of control device 20. Control device 20B has a control unit 21B instead of control unit 21. Control unit 21B has a refresh timing determination unit 212B instead of refresh timing determination unit 212, and has an evaluation value calculation unit 213B instead of evaluation value calculation unit 213.

[0077] The installation angle detection unit 5 detects the installation angle of the display panel 10. In this embodiment, the installation angle of the display panel 10 refers to the angle that the display surface of the display panel 10 makes with respect to the horizontal plane.

[0078] The refresh timing determination unit 212B determines the refresh timing based on the angle θ detected by the installation angle detection unit 5. The display control unit 211 executes a refresh operation at the determined refresh timing.

[0079] Therefore, the refresh timing is determined based on the angle θ detected by installation angle detection unit 5. As a result, it is possible to suppress degradation of display quality caused by the installation angle of electronic paper 100B.

[0080] As shown in FIGS. 7A to 7C, an installation angle detection unit 5 is built in near the upper rear surface of electronic paper 100B. However, installation angle detection unit 5 may be built in somewhere other than near the upper rear surface, or may be located outside the rear surface of electronic paper 100B. Installation angle detection unit 5 detects the installation angle of display panel 10 and transmits the detected angle θ to control unit 21B. Control unit 21B acquires the detected angle θ from installation angle detection unit 5.

[0081] As shown in Fig. 7A, if electronic paper 100B is installed vertically, the detection angle θ is 90 degrees. As shown in Fig. 7B, if electronic paper 100B is installed at a 45-degree angle, the detection angle θ is 45 degrees. As shown in Fig. 7C, if electronic paper 100B is installed horizontally, the detection angle θ is 0 degrees. Note that Figs. 7A to 7C do not show a specific configuration for supporting electronic paper 100B at an arbitrary installation angle.

[0082] The installation angle detection unit 5 may be, for example, a tilt sensor that measures the tilt from a horizontal position based on gravity and outputs an electrical signal corresponding to the measured installation angle, but is not limited to this. Examples of tilt sensors include an electrolyte type, a MEMS (Micro Electro Mechanical Systems) type, and a quartz type. A sensor that can measure tilt along one axis, two axes, or three axes may be selected as needed. For example, a one-axis tilt sensor may be selected, and the measured installation angle may be output as the detected angle θ. Alternatively, a two- or three-axis tilt sensor may be selected, and the detected angle θ may be calculated by computation from the measurement output of each axis.

[0083] The installation angle detection unit 5 may include, for example, a triaxial acceleration sensor. Therefore, the installation angle of the display panel 10 is calculated from the accelerations of the three axes detected by a single triaxial acceleration sensor. As a result, if there is not much difference in size between the single-axis tilt sensor and the triaxial acceleration sensor, the installation space can be reduced compared to installing three single-axis tilt sensors. Furthermore, compared to installing only one single-axis tilt sensor, the detection angles of the three axes can be used more effectively.

[0084] If a triaxial acceleration sensor is used as the installation angle detection unit 5, the detected angle θ can be obtained for each axis. That is, the detected angle θ has a component for each axis. Furthermore, it is possible to distinguish between a state in which the display panel 10 is installed horizontally, as shown in FIG. 8A, and a state in which the display panel 10 is installed rotated vertically, as shown in FIG. 8B. Note that FIGS. 8A and 8B illustrate a configuration in which the electronic paper 100B is supported by a stand 32 and an attachment unit 31 that attaches the stand 32 to the rear surface of the electronic paper 100B. However, the present invention is not limited to this configuration.

[0085] 2.2 Details of the control unit 21B The refresh timing determination unit 212B and the evaluation value calculation unit 213B included in the control unit 21B have functions corresponding to the installation angle detection unit 5.

[0086] The evaluation value calculation unit 213B calculates the evaluation value E2 based on the history of the detected angle .theta.. The refresh timing determination unit 212 determines the timing at which the evaluation value E2 satisfies the first condition as the refresh timing.

[0087] Therefore, the evaluation value E2 is calculated based on the history of the detected angle θ, and the timing at which the evaluation value E2 satisfies the first condition is determined as the refresh timing. As a result, it is possible to further suppress degradation of display quality caused by the history of the installation angle of the electronic paper 100B.

[0088] For example, the evaluation value calculation unit 213B may calculate an evaluation value E2 corresponding to the detected angle θ for each time in the history of the detected angle θ. Here, the first condition is, for example, that the time-integrated value of the evaluation value E2 is equal to or greater than a preset time-integrated threshold value.

[0089] Therefore, for each time in the history of the detected angle θ, an evaluation value E2 corresponding to the detected angle θ is calculated, and the timing at which the time-integrated value of the evaluation value E2 becomes equal to or greater than a preset time-integrated threshold is determined as the refresh timing. As a result, even if a long period of time has passed at an unusual installation angle, deterioration of display quality can be accurately suppressed.

[0090] 2.3 Control method of electronic paper 100B Next, a control method for electronic paper 100B will be described with reference to FIG. 9. FIG. 9 is a flowchart for describing the control method for electronic paper 100B. The control method for electronic paper 100B includes steps S11 to S15. Step S12 is an example of a "step of detecting an installation angle" in the present disclosure. Step S3 is an example of a "step of performing a write operation" in the present disclosure. Step S14 is an example of a "step of determining refresh timing" in the present disclosure. Step S15 is an example of a "step of performing a refresh operation" in the present disclosure.

[0091] 9, in step S11, the control unit 21A obtains image data relating to the display image after writing. This process is the same as step S1 in FIG.

[0092] In step S12, installation angle detection unit 5 detects the installation angle of display panel 10. Specifically, installation angle detection unit 5 detects the installation angle of display panel 10 and transmits the detected angle θ to control unit 21B. Control unit 21B acquires the detected angle θ from installation angle detection unit 5.

[0093] In step S13, the display control unit 211 executes a write operation to write an image to the display panel 10. The display control unit 211 executes the write operation by applying a voltage to the color particles 132. This process is the same as step S3 in FIG. 4 described above.

[0094] In step S14, the refresh timing determination unit 212 determines the refresh timing, which is the timing to execute a refresh operation to perform another write operation after the immediately preceding write operation, based on the angle θ detected in step S12.

[0095] In step S15, the display control unit 211 executes a refresh operation at the refresh timing determined in step S14.

[0096] Therefore, the refresh operation is performed based on the detected angle .theta.. As a result, it is possible to suppress degradation of display quality caused by the installation angle of electronic paper 100B.

[0097] 2.4 Modification of the second embodiment Next, a modified example of the second embodiment of the present disclosure will be described with reference to Fig. 10. Fig. 10 is a block diagram showing the configuration of electronic paper 100C according to a modified example of the second embodiment of the present disclosure. Differences from the second embodiment will be mainly described below.

[0098] 10, in comparison with the configuration of electronic paper 100B described above (see FIG. 6), electronic paper 100C includes a control device 20C instead of control device 20B, and further includes a brightness detection unit 4. Control device 20C has a control unit 21C instead of control unit 21B. Control unit 21C further includes a clock unit 214.

[0099] In this configuration, the display control unit 211 functions in the same manner as in the modified example of the first embodiment described above. Therefore, even if the refresh timing determined based on the installation angle of the display panel 10 arrives, execution of the refresh operation is suspended until the second condition is satisfied. As a result, it is possible to avoid a situation in which the display content of the display panel 10 becomes temporarily unreadable due to the refresh operation being executed at an inadvertent timing.

[0100] The suspended refresh operation is executed when the second condition is subsequently satisfied. For example, the refresh operation is executed by selecting a time period or a lighting condition (e.g., a dark environment) in which temporary inability to read the display content on the display panel 10 will not cause any problems.

[0101] Third Embodiment 3.1 Functional configuration of e-paper 100D Next, a third embodiment of the present disclosure will be described with reference to Fig. 11. Fig. 11 is a block diagram showing the configuration of electronic paper 100D according to the third embodiment of the present disclosure. The following mainly describes differences from the modified example of the second embodiment.

[0102] 11, in comparison with the configuration of electronic paper 100C described above (see FIG. 10), electronic paper 100D includes control device 20D instead of control device 20C, and further includes temperature sensor 2. Control device 20D has control device 21D instead of control device 21C. Control device 21D has refresh timing determination unit 212D instead of refresh timing determination unit 212B, and has evaluation value calculation unit 213D instead of evaluation value calculation unit 213B.

[0103] The evaluation value calculation unit 213D calculates an evaluation value E1 based on the history of the detected temperature T, similar to the above-described evaluation value calculation unit 213, and calculates an evaluation value E2 based on the history of the detected angle θ, similar to the above-described evaluation value calculation unit 213B. Then, based on the evaluation values E1 and E2, the evaluation value calculation unit 213D may calculate an evaluation value E3, for example, according to the following equation: where w1 and w2 are weighting coefficients. Evaluation value E3 = w1 × E1 + w2 × E2 However, the method of calculating the evaluation value E3 is not limited to this example.

[0104] The refresh timing determination unit 212D may determine the timing at which the evaluation value E3 satisfies the first condition as the refresh timing. Therefore, the refresh timing is determined to be the timing at which the evaluation value E3 calculated based on the history of the detected temperature T and the history of the detected angle θ satisfies the first condition. As a result, it is possible to suppress degradation of display quality caused by the temperature history of the installation environment and the installation angle history.

[0105] The evaluation value calculation unit 213D may also evaluate factors other than the temperature history of the installation environment and the installation angle history. For example, if a triaxial acceleration sensor is used as the installation angle detection unit 5, the evaluation value calculation unit 213D may also evaluate the vibration intensity history that can be detected by the triaxial acceleration sensor.

[0106] In this case, the timing at which the evaluation value E calculated based on the history of the detected temperature T, the history of the detected angle θ, and the history of the vibration strength satisfies the first condition is determined as the refresh timing. As a result, it is possible to suppress degradation of display quality caused by not only the temperature history and the installation angle history of the installation environment but also the vibration strength history.

[0107] The embodiments of the present disclosure have been described above with reference to the drawings. However, the present disclosure is not limited to the above embodiments and can be implemented in various forms without departing from the spirit and scope of the present disclosure. Furthermore, various disclosures can be formed by appropriately combining multiple components disclosed in the above embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. The drawings mainly show each component in a schematic manner to facilitate understanding, and the thickness, length, number, spacing, etc. of each illustrated component may differ from the actual components due to the convenience of drawing. Furthermore, the materials, shapes, dimensions, etc. of each component shown in the above embodiments are merely examples and are not particularly limited, and various modifications are possible within a scope that does not substantially deviate from the effects of the present disclosure.

[0108] For example, in the above embodiment, an example has been described in which the present disclosure is applied to a microcapsule-type electronic paper 100 having microcapsules 13, but the present disclosure is not limited to this. For example, the present disclosure may be applied to electronic paper that does not have microcapsules 13 but has color particles 132. The present disclosure may also be applied to twist ball-type electronic paper in which the surfaces of color particles are painted in two colors on each hemisphere, and a display image is written by rotating the color particles. [Industrial Applicability]

[0109] The present disclosure is useful in the field of electronic paper. [Explanation of symbols]

[0110] 2: Temperature sensor 4: Brightness detection section 5: Installation angle detection section 10: Display panel 14:1st electrode 15, 15a, 15b: 2nd electrode 20, 20A, 20B, 20C, 20D: Control device 21, 21A, 21B, 21C, 21D: Control section 211: Display control unit 212, 212B, 212D: Refresh timing determination unit 213, 213B, 213D: Evaluation value calculation unit 214: Clock section 100, 100A, 100B, 100C, 100D: Electronic paper 132: Color particles 132a: Black particles (color particles) 132b: White particles (color particles) S2: Step (temperature detection process) S3: Step (process for executing write operation) S4: Step (process for determining refresh timing) S5: Step (process for performing refresh operation) S12: Step (process for detecting the installation angle of the display panel) S13: Step (process for executing write operation) S14: Step (step for determining refresh timing) S15: Step (process for performing refresh operation)

Claims

1. a display panel including color particles that move when a voltage is applied; an installation angle detection unit that detects an installation angle of the display panel; a display control unit that controls a writing operation for writing an image onto the display panel by applying a voltage to the color particles; a refresh timing determination unit that determines a refresh timing for executing a refresh operation, which is an operation for performing the write operation again after the immediately preceding write operation; Equipped with the refresh timing determination unit determines the refresh timing based on the angle detected by the installation angle detection unit; The display control unit executes the refresh operation at the determined refresh timing.

2. an evaluation value calculation unit that calculates an evaluation value based on the history of the detected angles; The electronic paper according to claim 1 , wherein the refresh timing determination unit determines, as the refresh timing, a timing at which the evaluation value satisfies a first condition.

3. the evaluation value calculation unit calculates the evaluation value corresponding to the detected angle for each time in the history of the detected angle; The electronic paper according to claim 2 , wherein the first condition is that a time-integrated value of the evaluation value is equal to or greater than a preset time-integrated threshold value.

4. The electronic paper according to claim 2 or 3, wherein the display control unit executes the refresh operation when a second condition is met at the refresh timing, and suspends execution of the refresh operation when the second condition is not met at the refresh timing.

5. The electronic paper according to claim 4 , wherein, when the display control unit has suspended the execution of the refresh operation, the display control unit executes the refresh operation when the second condition is satisfied.

6. Further comprising a clock unit that measures at least the time, The electronic paper according to claim 4 , wherein the second condition is that the time is included in a preset time period.

7. Further comprising a brightness detection unit that detects the brightness of the surroundings, The electronic paper according to claim 4 , wherein the second condition is that the brightness detected by the brightness detection unit is equal to or less than a preset brightness threshold value.

8. The electronic paper according to any one of claims 1 to 3, wherein the refresh operation is an operation of applying a second voltage different from a first voltage corresponding to the display gradation after the refresh operation, and then applying the first voltage.

9. The electronic paper according to claim 8 , wherein the display gray scale after the refresh operation is the same as the display gray scale before the refresh operation.

10. The electronic paper according to claim 1 , wherein the installation angle detection unit includes a three-axis acceleration sensor.

11. A method for controlling electronic paper having a display panel including color particles that move when a voltage is applied, comprising: detecting an installation angle of the display panel; performing a write operation to write an image onto the display panel by applying a voltage to the color particles; determining a refresh timing for executing a refresh operation for performing the write operation again after the immediately preceding write operation based on the detected installation angle; performing the refresh operation at the determined refresh timing; A method for controlling electronic paper, including:

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