Electronic paper and control method of electronic paper

Abstract

To provide electronic paper capable of suppressing a deterioration in display quality due to vibration.SOLUTION: Electronic paper includes a display panel, a vibration detection part, and a control part. The display panel has pixels including color particles which move according to applied voltage. The vibration detection part detects vibration (S11). When such a condition that a predetermined level or more of the vibration is not detected by the vibration detection part is satisfied (S13, S16), the control part writes an image in the display panel by the application of the voltage to the pixels (S14, S17).SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Conventionally, electronic paper using microcapsules containing black and white electrophoretic particles has been known (see, for example, Patent Document 1). Such electronic paper retains the displayed image even after the application of voltage to the pixels is stopped after the image is displayed, but the contrast tends to decrease over time. Therefore, the electronic paper described in Patent Document 1 performs an image retention step to retain the image after writing the image to the pixels, and then performs a refresh step after a predetermined time has passed. In the image retention step, the electrophoretic particles in the pixels are not driven, while in the refresh step, the electrophoretic particles in the pixels are driven, and the image written before the image retention step is rewritten to the pixels. [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] Incidentally, when electronic paper is installed on a train, bus, etc., the electronic paper is subjected to vibrations from the train, bus, etc. In the case of electronic paper such as that described in Patent Document 1, due to its structure, vibrations may adversely affect the movement of electrophoretic particles, and writing an image to pixels during vibrations is likely to result in a deterioration in display quality.

[0005] An object of the present disclosure is to provide electronic paper that can suppress degradation of display quality due to vibration. [Means for solving the problem]

[0006] The electronic paper of the present disclosure includes a display panel, a vibration detection unit, and a control unit. The display panel has pixels containing color particles that move in response to an applied voltage. The vibration detection unit detects vibration. The control unit applies a voltage to the pixels to write an image on the display panel. The control unit writes an image when a condition is met in which the vibration detection unit does not detect vibrations above a predetermined level.

[0007] The electronic paper control method of the present disclosure is a control method for electronic paper equipped with a display panel having pixels including color particles that move in response to an applied voltage, and includes a vibration detection step and a writing step. The vibration detection step detects vibration. The writing step writes an image on the display panel. The writing step writes when a condition is met that vibrations equal to or greater than a predetermined level are not detected in the vibration detection step. [Effects of the Invention]

[0008] According to the present disclosure described above, it is possible to suppress deterioration of display quality due to vibrations. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view schematically showing the structure of electronic paper according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing a schematic configuration of the electronic paper shown in FIG. [Figure 3] FIG. 3 is a schematic enlarged view of a part of the display panel shown in FIG. [Figure 4] FIG. 4 is an operational flow diagram showing the writing process of electronic paper in the embodiment. [Figure 5] FIG. 5 is a block diagram showing a schematic configuration of electronic paper in the modification (1). 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] Fig. 1 is a cross-sectional view showing a schematic structure of electronic paper 100 according to an embodiment of the present invention. Fig. 2 is a block diagram showing a schematic configuration of electronic paper 100 shown in Fig. 1.

[0012] The electronic paper 100 is a display device that displays images. The electronic paper 100 may be used, for example, as an electronic shelf label, an electronic advertisement, an electronic book terminal, or an electronic notebook, or may be used in other devices. In this embodiment, the electronic paper 100 is installed as an electronic advertisement in a moving object such as a train. The configuration of the electronic paper 100 will be described below with reference to FIGS. 1 and 2.

[0013] 1 and 2, the electronic paper 100 includes a housing 1, a display panel 10, a control device 20, a communication unit 30, a vibration detection unit 40, and a timing unit 50. Although not shown, the electronic paper 100 may further include an operation button (not shown) such as a power button that accepts user operations. The electronic paper 100 may also include a touch panel on the surface of the display panel 10 that accepts user operations.

[0014] 1, a housing 1 houses a display panel 10. The housing 1 has an opening 1a on the front surface.

[0015] The display panel 10 displays an image. The display panel 10 is formed 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.

[0016] The display panel 10 also includes a first substrate 11, a second substrate 12, a microcapsule layer 13, a first electrode 14, and a second electrode 15. Although not shown, the display panel 10 also includes a drive circuit that drives the first electrode 14 and the second electrode 15.

[0017] The first substrate 11 and the second substrate 12 are disposed opposite to each other with the microcapsule layer 13, the first electrode 14, and the second electrode 15 sandwiched therebetween. 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 surface of the first substrate 11 opposite to the second substrate 12, or the surface may be treated with a water-repellent coating. The second substrate 12 is formed of a plate or sheet member such as glass or resin.

[0018] Fig. 3 is a schematic enlarged view of a cross section of the display panel 10 shown in Fig. 1. As shown in Fig. 3, the microcapsule layer 13 includes a plurality of microcapsules 130a to 130c each having a substantially spherical shape. Hereinafter, when there is no need to distinguish between the microcapsules, they will be referred to as microcapsules 130.

[0019] The microcapsules 130 have a diameter of, for example, several tens of μm or more and several hundreds of μm or less. The microcapsules 130 include a membrane 131, a plurality of color particles 132, and a dispersion liquid 133.

[0020] The film 131 is made of, for example, 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.

[0021] The dispersion liquid 133 is, for example, a transparent liquid having insulating properties, and may contain, for example, water, an alcohol-based solvent, an ester, a ketone, an aliphatic hydrocarbon, an alicyclic hydrocarbon, an aromatic hydrocarbon, or an oil.

[0022] The color particles 132 are particles made of organic or inorganic pigments. In this embodiment, the color particles 132 include, for example, black particles 132a made of black pigments and white particles 132b made of white pigments. For example, the black particles 132a are carbon black or titanium black, and the white particles 132b are titanium dioxide or antimony trioxide. In this embodiment, for example, the black particles 132a are negatively charged, and the white particles 132b are positively charged. In other words, the black particles 132a and the white particles 132b are different in color and charged with different polarities. Note that the black particles 132a may be positively charged, and the white particles 132b may be negatively charged.

[0023] The color particles 132 are electrophoretic particles that move in response to a voltage applied to a pixel in which the color particles 132 are arranged. 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. This causes an image to be displayed on the display panel 10. In this embodiment, movement includes the movement and rotation of the color particles 132.

[0024] The color particles 132 are not limited to white and black pigments and may contain pigments of other colors. Furthermore, the color particles 132 may contain pigments of other colors in addition to white and black pigments. Examples of pigments of other colors that may be used include yellow pigments, red pigments, blue pigments, and green pigments.

[0025] The first electrode 14 and the second electrode 15 are disposed opposite to each other with the microcapsule 130 sandwiched therebetween.

[0026] The first electrodes 14 are provided on the first substrate 11 in contact with the microcapsules 130 so as to overlap all pixels of the display panel 10. The first electrodes 14 are formed of a light-transmitting conductive material such as ITO. The first electrodes 14 are, for example, grounded and have a ground potential.

[0027] The second electrodes 15 are arranged in a matrix on the second substrate 12 in contact with the microcapsules 130. The second electrodes 15 are made of, for example, a metal material such as copper.

[0028] In this embodiment, the first electrode 14 is a common electrode, and the second electrode 15 is a pixel electrode. That is, each pixel has the first electrode 14 and the second electrode 15 with the color particles 132 sandwiched between them.

[0029] FIG. 3 illustrates a state in which a positive potential is applied to some of the second electrodes 15a to 15c (15), and a negative potential is applied to the other second electrodes 15d to 15f (15).

[0030] 3, a positive potential is applied to the two second electrodes 15a and 15b in contact with the microcapsule 130a, causing the black particles 132a in the microcapsule 130a to move toward the second electrodes 15a and 15b, and the white particles 132b to move toward the first electrode 14.

[0031] A positive potential is applied to one second electrode 15c in contact with microcapsule 130b, and a negative potential is applied to the other second electrode 15d. As a result, some of the black particles 132a in microcapsule 130b move toward second electrode 15c, while other black particles 132a move toward first electrode 14, which faces second electrode 15d. Furthermore, some of the white particles 132b in microcapsule 130b move toward first electrode 14, which faces second electrode 15c, while other white particles 132b move toward second electrode 15d.

[0032] A negative potential is applied to the two second electrodes 15e and 15f in contact with the microcapsule 130c, so that the white particles 132b in the microcapsule 130c move toward the second electrodes 15e and 15f, and the black particles 132a move toward the first electrode 14.

[0033] In this way, the black particles 132a and the white particles 132b move toward the first electrode 14 or the second electrode 15 depending on the voltage applied to the pixel, thereby displaying an image in the display area.

[0034] Under the control of the control device 20, a drive circuit (not shown) applies a voltage between the first electrode 14 and the second electrode 15 according to the gradation of an image to be displayed in the display area. In this embodiment, for example, a monochrome image with 16 gradations ranging from gradation levels "0" (black) to "15" (white) can be displayed for each pixel, with the voltage corresponding to gradation level 0 being "-5V" and the voltage corresponding to gradation level "15" being "+5V." When a black image is to be displayed over the entire display area, "-5V" is applied between the first electrode 14 and the second electrode 15. When a white image is to be displayed over the entire display area, "+5V" is applied between the first electrode 14 and the second electrode 15.

[0035] Returning to FIGS. 1 and 2, the communication unit 30, the vibration detection unit 40, and the control device 20 will be described.

[0036] The communication unit 30 is, for example, a communication interface such as a wireless network interface controller. The communication unit 30 communicates with a personal computer or the like via a communication network such as the Internet or a public telephone network. The communication unit 30 is capable of receiving an instruction signal from an instruction terminal (not shown) such as a personal computer. The communication unit 30 may also be capable of transmitting and receiving signals to and from the instruction terminal (not shown). The communication unit 30 may also be, for example, an interface device for wired communication.

[0037] The vibration detection unit 40 is provided inside the housing 1. The vibration detection unit 40 is, for example, a three-axis acceleration sensor, and detects accelerations in the X, Y, and Z axis directions shown in FIG. 1. The vibration detection unit 40 is not limited to a three-axis acceleration sensor, and may be a two-axis acceleration sensor. The vibration detection unit 40 outputs the detection result to the control device 20 every fixed time (for example, every 10 seconds).

[0038] The timekeeping unit 50 keeps track of time.

[0039] The control device 20 includes a control unit 21 and a storage unit 22 .

[0040] 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 also include removable media.

[0041] The storage unit 22 stores data and computer programs. The data includes, for example, image data related to a display image to be displayed on the display panel 10. The storage unit 22 also stores the detection results of the vibration detection unit 40 under the control of the control unit 21.

[0042] The control unit 21 includes a processor. The control unit 21 includes, for example, a central processing unit (CPU). Alternatively, the control unit 21 may include a general-purpose computer.

[0043] The control unit 21 controls each unit connected to the control device 20 and controls the display of images on the display panel 10 by causing the CPU to execute a computer program stored in the storage unit 22. Specifically, the control unit 21 performs first writing and second writing on the display panel 10.

[0044] The first writing is a process of writing an image to the display panel 10 based on a writing instruction from, for example, an instruction terminal (not shown). The control unit 21 performs the first writing by applying a voltage corresponding to the gradation of the image data based on the writing instruction to each pixel using a drive circuit (not shown). The image data based on the writing instruction may be stored in the storage unit 22 or may be received via the communication unit 30.

[0045] The second writing is a so-called refresh process in which, at a predetermined refresh timing, an image that was most recently written to the display panel 10 (hereinafter referred to as the most recently displayed image) is written again to the display panel 10. The predetermined refresh timing is, for example, a predetermined time or every few hours, or other timing that is set in advance. In this embodiment, the predetermined refresh timing is, for example, midnight.

[0046] The second writing includes a process of writing a refresh image different from the most recently displayed image to the display panel 10. After the refresh image writing process, the control unit 21 writes the most recently displayed image to the display panel 10. In this embodiment, the refresh image is, for example, an image in which the entire display area is white or black. The process of writing the refresh image is performed by applying to the pixels a voltage (an example of a second voltage) different from a voltage (an example of a first voltage) corresponding to the gradation of the most recently displayed image. In the second writing, the control unit 21 stores image data of the most recently displayed image in advance in memory before writing the refresh image.

[0047] In this embodiment, the first write and the second write are performed when a condition related to vibration (hereinafter referred to as the vibration condition) based on the detection result of the vibration detection unit 40 is satisfied. The vibration condition is that vibration of a predetermined level or more is not detected. In other words, the first write is performed when the vibration condition is satisfied at the time of a write instruction. The second write is performed when the vibration condition is satisfied at a predetermined refresh timing.

[0048] The control unit 21 detects vibrations based on the detection result of the vibration detection unit 40. For example, the control unit 21 calculates the acceleration values (x, y, z) of the X, Y, and Z axes every 10 seconds as scalar values (x 2 +y 2 +z 2 ) and if the calculated value is equal to or greater than the threshold and fluctuates periodically, it is determined that vibrations of a predetermined level or greater are occurring.

[0049] (operation) The operation of the electronic paper 100 of this embodiment will be described with reference to Fig. 4. Fig. 4 is an operational flow diagram showing the writing process of the electronic paper 100. The operational flow in Fig. 4 starts when the power button of the electronic paper 100 is turned on and, for example, an image based on a writing instruction from an instruction terminal (not shown), or a default image at power-on, is displayed on the display panel 10.

[0050] In step S11, control unit 21 starts detecting vibrations. Specifically, control unit 21 acquires acceleration values (x, y, z) detected by vibration detection unit 40, for example, every 10 seconds, stores them in storage unit 22, and detects vibrations from the acceleration values.

[0051] If the current time is the predetermined refresh timing (step S12: Yes) and the vibration condition is satisfied at this timing (step S13: Yes), the control unit 21 performs the second writing (step S14).

[0052] Specifically, the control unit 21 determines that the predetermined refresh timing has occurred if the time measured by the clock unit 50 is midnight. Furthermore, the control unit 21 determines that the vibration condition is met if, at the predetermined refresh timing, vibrations of a predetermined level or greater are not detected based on the acceleration values acquired from the vibration detection unit 40. The control unit 21 then reads image data of the most recently displayed image displayed on the display panel 10 from the storage unit 22, stores the data in memory, and writes, for example, a refresh image whose entire display area is white to the display panel 10. The white refresh image is written, for example, by applying "+5V" between the first electrode 14 and each second electrode 15 by a drive circuit (not shown). After the refresh image has been written to the display panel 10, the control unit 21 applies a voltage between the first electrode 14 and each second electrode 15 corresponding to the grayscale of the image data of the most recently displayed image stored in memory, thereby writing the most recently displayed image to the display panel 10 again.

[0053] In step S13, if the control unit 21 determines that the vibration condition is not satisfied (step S13: No), it waits until the vibration condition is satisfied. That is, the control unit 21 determines that the vibration condition is not satisfied if vibration of a predetermined level or more is detected based on the acceleration value acquired from the vibration detection unit 40. Then, the control unit 21 suspends the second writing until the vibration condition is satisfied, and performs the second writing when the vibration condition is satisfied.

[0054] Furthermore, if the current time is not the predetermined refresh timing in step S12 (step S12: No) and a write instruction is received (step S15: Yes), the control unit 21 determines whether or not the vibration condition is satisfied (step S16). That is, when the control unit 21 receives a write instruction from, for example, an instruction terminal (not shown) via the communication unit 30, the control unit 21 determines whether or not the vibration condition is satisfied based on the acceleration value acquired from the vibration detection unit 40, similar to step S13.

[0055] In step S16, if the control unit 21 determines that the vibration condition is satisfied (step S16: Yes), it performs a first write (step S17). Specifically, the control unit 21 reads out the image data specified in the write instruction from the storage unit 22. Then, the control unit 21 applies a voltage corresponding to the gradation of the read image data between the first electrode 14 and each second electrode 15 using a drive circuit (not shown), thereby writing an image corresponding to the write instruction onto the display panel 10.

[0056] In step S16, if the control unit 21 determines that the vibration condition is not satisfied (step S16: No), the control unit 21 waits until the vibration condition is satisfied. That is, the control unit 21 suspends the first writing until the vibration condition is satisfied, and performs the first writing when the vibration condition is satisfied.

[0057] In step S15, if the control unit 21 does not accept a write instruction (step S15: No), it performs the processes from step S12 onwards.

[0058] After step S14 or step S17, the control unit 21 performs the processes from step S12 onwards until the user turns off the power (step S18: No). Then, when the user turns off the power in step S17 (step S18: Yes), the control unit 21 ends the write process.

[0059] In the above-described embodiment, the first writing or the second writing is performed when a vibration condition is satisfied at a write instruction or a predetermined refresh timing. If the first writing and the second writing are performed on the display panel 10 when vibrations of a predetermined level or above are occurring, the color particles 132 are likely to be affected by the vibrations and the display quality is likely to deteriorate. Therefore, by performing the first writing and the second writing when vibrations of a predetermined level or above are not occurring, deterioration of the display quality is suppressed.

[0060] In the above-described embodiment, in the second writing, before the most recently displayed image is written, a voltage (second voltage) different from the voltage (first voltage) corresponding to the gradation of the image (most recently displayed image) to be displayed after the second writing is applied to each pixel. Specifically, after a refresh image in which the entire display area is white or black, for example, is written to the display panel 10, the most recently displayed image is written again to the display panel 10. That is, the white particles 132b and the black particles 132a in the microcapsules 130 are moved to electrodes on opposite sides, and then the most recently displayed image is written. This reduces the number of color particles 132 that cannot be moved within the microcapsules 130, making it less likely that the contrast of the image will decrease.

[0061] In the embodiment, even if the vibration condition is not satisfied at the timing when the writing instruction is received, the first writing may be forcibly performed in response to an instruction from an instruction terminal (not shown), for example. In other words, of the first writing and the second writing, at least the second writing may be performed at a timing when the vibration condition is satisfied. By configuring in this way, it is possible to avoid impairing the convenience for the user.

[0062] 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.

[0063] <Modification> (1) In the embodiment, the predetermined refresh timing is a predetermined time (e.g., 24:00), but the refresh timing may be varied depending on the vibration. Specifically, the refresh timing may be determined as the timing when the accumulated time during which vibrations at a predetermined level or higher occur (hereinafter referred to as the vibration accumulated value) exceeds a predetermined time. In this case, the second writing may be suspended until the vibration condition is satisfied at the determined refresh timing, and the second writing may be performed when the vibration condition is satisfied. Display quality is likely to deteriorate when vibrations at a predetermined level or higher continue for a long period of time. Therefore, when vibrations at a predetermined level or higher continue for a predetermined period of time or longer, the display quality can be more easily maintained by performing the second writing before the display quality deteriorates.

[0064] The refresh timing is not limited to the above. For example, the integrated value of the vibration time may be weighted according to the vibration level, and the timing when the weighted integrated value becomes equal to or greater than a threshold may be determined as the refresh timing. For example, the weighting may be increased as the vibration level increases. By configuring in this way, the second writing is performed when a relatively large vibration occurs even for a short period of time, thereby suppressing a decrease in display quality.

[0065] (2) In the embodiment, the predetermined refresh timing may be varied depending on the temperature inside the housing 1 (see FIG. 1). FIG. 5 is a block diagram showing a schematic configuration of electronic paper 100A in this modification. In FIG. 5, the same components as those in the embodiment are assigned the same reference numerals. The following mainly describes the components that differ from the embodiment.

[0066] As shown in FIG. 5, the electronic paper 100A includes a control device 20A and a temperature detection unit 60.

[0067] The temperature detection unit 60 includes, for example, a temperature sensor, and is provided inside the housing 1. The temperature detection unit 60 detects the temperature inside the housing 1 at regular intervals, and outputs the detection result to the control device 20A.

[0068] The control device 20A includes a control unit 21A and a storage unit 22A. The storage unit 22A stores the detection results obtained from the temperature detection unit 60 in addition to the detection results obtained from the vibration detection unit 40 under the control of the control unit 21A.

[0069] The control unit 21A controls each unit connected to the control device 20A to perform first writing and second writing on the display panel 10. The control unit 21A also determines the refresh timing based on the detection result of the temperature detection unit 60. Specifically, the control unit 21A may determine, for example, the timing when the accumulated time during which the detected temperature is equal to or higher than a predetermined temperature exceeds a threshold as the refresh timing. The control unit 21A performs the second writing at the determined refresh timing if a vibration condition is satisfied.

[0070] The contrast of the electronic paper 100 is likely to decrease due to continued display in a high-temperature environment. Therefore, by performing the second writing before the contrast decreases due to the temperature inside the housing 1, the decrease in contrast can be suppressed.

[0071] (3) In the embodiment, the predetermined refresh timing may be changed depending on the orientation of the housing 1 (see FIG. 1).

[0072] The orientation of the housing 1 may be detected in the control unit 21 using the acceleration values (x, y, z) output from the vibration detection unit 40. In the orientation of the housing 1 shown in FIG. 1, acceleration equivalent to gravity occurs in the negative Z-axis direction, and the acceleration in the X and Y-axis directions is approximately zero. On the other hand, in an orientation in which the display surface of the display panel 10 is parallel to the direction of gravity, acceleration equivalent to gravity occurs in the X-axis direction, and the acceleration in the Y and Z-axis directions is approximately zero.

[0073] If the housing 1 is kept tilted for a long period of time so that the display surface of the display panel 10 (FIG. 1) is parallel to the direction of gravity, the color particles 132 in the display panel 10 are likely to be affected by gravity and the contrast will decrease. Therefore, in this modification, the predetermined posture is one in which the display surface of the display panel 10 is parallel to the direction of gravity, and the second writing is performed before the contrast decreases due to the predetermined posture. Note that the predetermined posture is not limited to this, and may be, for example, a posture in which the display surface of the display panel 10 is oriented in the same direction as the direction of gravity.

[0074] The control unit 21 may determine, as the refresh timing, the timing at which the accumulated time during which the casing 1 is in a predetermined posture exceeds a threshold value based on the acceleration value output from the vibration detection unit 40. Then, the control unit 21 performs the second writing at the determined refresh timing if the vibration condition is satisfied.

[0075] (4) The predetermined refresh timing may be determined by combining the modifications (2) and (3). For example, the timing when the accumulated time during which the detected temperature inside the housing 1 is equal to or higher than the predetermined temperature exceeds a temperature threshold, or the timing when the accumulated time during which the housing 1 is in a predetermined posture exceeds a posture threshold, may be determined as the refresh timing based on the timing when the threshold is exceeded first.

[0076] (5) In the modifications (2) and (3), if the determined refresh timing falls outside a predetermined time period, the second writing may be postponed until the predetermined time period arrives, and the second writing may be performed at a time when there is no vibration during the predetermined time period. The predetermined time period may be, for example, a time period when a moving object, such as a train on which the electronic paper 100 or 100A is installed, is not in operation. By performing the second writing during a time period when the moving object is not in operation, it is possible to suppress a decrease in contrast without causing discomfort to passengers.

[0077] (6) In the embodiment and the modified examples, the refresh image may be an image obtained by inverting the most recently displayed image. In short, it is sufficient that a voltage (second voltage) different from the voltage (first voltage) corresponding to the gradation of the image displayed in each pixel after the second write is applied to each pixel.

[0078] (7) In the embodiments and modifications, the electronic paper 100, 100A may be, for example, electronic paper that does not have microcapsules but has color particles 132. Alternatively, the electronic paper may be a twist ball type electronic paper in which the surface of the color particles is painted in two colors on each hemisphere, and a display image is written by rotating the color particles. [Industrial Applicability]

[0079] The present disclosure is useful in the field of electronic paper. [Explanation of symbols]

[0080] 1: Housing 10: Display panel 14: 1st electrode 15,15a~15f: 2nd electrode 20, 20A: Control device 21, 21A: Control section 22: Storage section 40: Vibration detection unit 60: Temperature detection unit 100,100A: Electronic paper 130, 130a-130c: Microcapsules 132,132a,132b: Color particles

Claims

1. a display panel having pixels containing color particles that move in response to an applied voltage; a vibration detection unit that detects vibrations; a control unit that applies the voltage to the pixels to write an image on the display panel; The control unit performs the writing when a condition is satisfied in which the vibration detection unit does not detect vibrations of a predetermined level or more.

2. The electronic paper according to claim 1, wherein the writing includes a first writing that writes an image to the display panel based on a writing instruction, and a second writing that rewrites an image that was previously written to the display panel at a predetermined refresh timing.

3. The electronic paper according to claim 2 , wherein the control unit suspends the second writing if the condition is not satisfied at the predetermined refresh timing, and performs the second writing when the condition is satisfied.

4. The electronic paper according to claim 2 or 3, wherein the control unit applies, as the second writing, a second voltage to the pixel that is different from a first voltage corresponding to the display gradation of the image displayed on the display panel after the second writing, and then applies the first voltage to the pixel.

5. The pixel in the display panel has a first electrode and a second electrode that are arranged opposite to each other with the color particles interposed therebetween, The color particles include first color particles and second color particles having different colors and being charged with opposite polarities, 5. The electronic paper according to claim 4, wherein the control unit applies the second voltage to the pixel in the second writing operation so that the first color particles and the second color particles move toward one of the first electrode and the second electrode, which is different from each other.

6. Further provided is a temperature detection unit for detecting a temperature, The electronic paper according to claim 2 or 3, wherein the control unit determines the predetermined refresh timing based on the temperature detected by the temperature detection unit.

7. further comprising an attitude detection unit that detects the attitude of the display panel; The electronic paper according to claim 2 or 3, wherein the control unit determines the predetermined refresh timing based on the orientation of the display panel detected by the orientation detection unit.

8. A method for controlling electronic paper having a display panel with pixels including color particles that move in response to an applied voltage, comprising: a vibration detection step of detecting vibration; a writing step of writing an image onto the display panel; The method for controlling electronic paper, wherein the writing step performs the writing when a condition is satisfied in which no vibration of a predetermined level or more is detected in the vibration detection step.

Images