JP2006267477A - Display medium and display medium controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for detecting the surrounding environmental status of a display medium while maintaining water-proofing property and moisture-proofing property in a display medium whose image deterioration is generated due to moisture. <P>SOLUTION: A wireless light quantity sensor 200L for executing radio communication by a radio signal as a measurement means for measuring light quantity to be emitted to a display medium 100. Thus, it is not necessary to connect the display medium 100 to an external controller 300 through any lead wire, and it is possible to enclose the display medium 100 by using the wireless light quantity sensor 200L. Thus, it is possible to measure the light quantity of the display medium 100 while maintaining water-proofing property and moisture-proofing property even when the image quality deterioration of the display medium 100 is generated due to moisture. Therefore, it is possible to control a driving voltage according to a measurement result. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for detecting an environmental condition around a display medium while maintaining waterproofness and moisture resistance in a display medium in which image degradation occurs due to humidity.

  In recent years, a display medium that performs image display using particles that move by an electric field is known as a display medium that can be repeatedly rewritten. For example, the image display device described in Patent Document 1 or Patent Document 2 is used between two types of colored particle groups (for example, used in a copying machine) charged with opposite polarities between a transparent display substrate and a back substrate. And the like, and an electric field is applied between the display substrate and the back substrate to move the two types of colored particle groups to different substrate sides, thereby forming an image. Power consumption required for image writing is small, and an image can be held without power after writing.

  Since the colored particles used in such a display medium have a characteristic that they do not move until the applied voltage exceeds a predetermined threshold value, line-shaped electrodes are provided on the display substrate and the back substrate, and each line is provided. Simple matrix driving that performs image display by sequentially applying voltages can be employed. Since the number of drive circuits can be reduced and the configuration can be simplified, a thin and light display panel can be realized even when the screen is enlarged. Therefore, it is expected that such a display medium is used as a large display medium such as an electronic bulletin board or an electronic poster.

By the way, in the display medium using the colored particles as described above, there is a problem that the image quality of the displayed image is deteriorated because the charge amount of the colored particles decreases when the humidity increases. For this reason, in particular, when this display medium is used outdoors as an electronic bulletin board or the like, it is necessary to isolate and seal it from the external environment for waterproofing and moisture-proofing.
JP 2001-31225 A JP 2004-086095 A

  By the way, in an electronic bulletin board used as a large display panel, image quality characteristics are detected by using various sensors such as a light quantity sensor and a temperature sensor in order to improve the image quality maintenance and reliability. The technique of performing is conventionally used. In this case, the image quality is controlled by connecting a sensor and a control device for receiving a signal from the sensor through a lead wire or the like.

  Here, a problem in the case where the image quality control is performed on the display medium in which the image quality is deteriorated due to the humidity as described above will be described with reference to FIG. In FIG. 17, 100 ′ is an electrically rewritable display medium, and includes a display unit 110 ′ that displays an image, a drive unit 120 ′ that applies a voltage to the display unit 110 ′, and a communication unit 150. ing. Reference numeral 300 ′ denotes a control device including a CPU (Central Processing Unit) for controlling the image quality of the display medium 100 ′, and the communication unit 150 and the control device 300 ′ of the display medium 100 ′ are connected by a lead wire W. . In such a configuration, even if an attempt is made to seal the inside of the display medium 100 ′ for waterproofing or moisture proofing, a gap is generated in the vicinity of the connection portion P between the display medium 100 ′ and the lead wire W, and thus the display medium 100 ′. Cannot be completely sealed, and moisture or moisture enters the display medium 100 ′ from the connecting portion P, resulting in a problem that the image quality is deteriorated.

  It is conceivable to seal the control device for controlling the image quality inside the display medium. In this case, however, it is necessary to seal all the sensors, control circuits, power supplies, lead wires, etc. inside the display medium. Problems such as an increase in thickness, an increase in thickness, or an increase in the cost of the display medium occur, and the advantage of the display medium that is thin and lightweight is lost. In particular, when image quality control is performed using a plurality of types of sensors, the number of sensors, lead wires, and the like provided inside increases, and this problem becomes significant. Further, since it is necessary to provide the control device inside the display medium, there is a problem that the performance of the control device is restricted.

  The present invention has been made in view of the above-described background, and an object of the present invention is to detect an environmental state around a display medium while maintaining waterproofness and moisture proofness in a display medium in which image degradation occurs due to humidity. Is to provide.

In order to achieve the above object, the present invention detects a physical quantity indicating an ambient environmental condition using a display medium layer for electrically switching display and a predetermined radio wave signal as an energy source. There is provided a display medium comprising: a wireless measurement unit that generates and outputs a radio signal having an attribute that reflects the physical quantity; and a sealing layer that covers and seals the wireless measurement unit.
In the present invention, even a display medium in which image degradation occurs due to humidity by using a wireless measurement unit that performs wireless communication using a radio wave signal as a measurement unit that measures a physical quantity indicating an environmental state around the display medium is waterproof. Thus, it is possible to detect the environmental condition around the display medium while maintaining the property and moisture resistance.

  The present invention also provides a display medium layer for electrically switching display, and when a predetermined radio wave signal is supplied, the physical quantity indicating the surrounding environmental state is detected using the signal as an energy source, and the detected physical quantity is reflected. And a wireless measurement means for generating and outputting a radio wave signal having the above-mentioned wireless measurement means, wherein the wireless measurement means is sealed in the display medium layer.

  In addition, the present invention provides a display medium layer that electrically switches display, a sealing layer that seals the display medium layer, and a physical quantity that indicates an ambient environmental condition using a predetermined radio wave signal as an energy source. And a wireless measuring means for generating and outputting a radio signal having an attribute reflecting the detected physical quantity, and the wireless measuring means is provided to be exposed to the sealing layer. I will provide a.

In a preferred aspect of the present invention, the display medium layer displays information to be displayed in a visible state by driving display particles by charging.
In another preferred aspect of the present invention, the physical quantity is at least one of light quantity, charge quantity, temperature, and humidity.
In another preferred aspect of the present invention, when a predetermined radio wave signal is supplied, the wireless measuring means detects a physical quantity indicating an ambient environmental condition using the signal as an energy source, and detects the detected physical quantity and identification information. A radio signal having an attribute that reflects the above is generated and output, and a plurality of the wireless measuring means are provided.
According to still another preferred aspect of the present invention, the wireless measuring device includes a plurality of types of the wireless measuring means that detect different physical quantities.

  Further, the present invention is a display medium control device for controlling the above-mentioned display medium, wherein the reception means receives a radio signal output from the wireless measurement means, and the radio signal received by the reception means Calculating means for calculating the physical quantity from the calculation means, and drive voltage control means for controlling the drive voltage of the display medium based on the physical quantity calculated by the calculation means.

  Further, the present invention is a display medium control device for controlling the above-mentioned display medium, wherein the reception means receives a radio signal output from the wireless measurement means, and the radio signal received by the reception means A display medium control apparatus comprising: a calculation unit that calculates a light amount from the calculation unit; and an adjustment unit that adjusts a contrast of an image displayed on the display medium based on the light amount calculated by the calculation unit. .

  In a preferred aspect of the present invention, the physical quantity is at least one of light quantity, charge quantity, temperature, and humidity.

  According to the present invention, in a display medium in which image degradation occurs due to humidity, it is possible to detect an environmental condition around the display medium while maintaining waterproofness and moisture resistance.

(1) First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
(1-1) Configuration First, the overall configuration of the system according to the first embodiment of the present invention will be described with reference to FIG. In the figure, reference numeral 100 denotes a display medium that can hold an image or the like without a power source. Reference numeral 300 denotes a control device that controls the image quality displayed on the display medium 100 by controlling the drive voltage of the display medium 100, and controls the drive voltage on the display medium 100 by wireless communication such as a wireless local area network (LAN). Instruction information indicating an instruction can be transmitted. In the display medium 100, reference numeral 110 denotes a display unit on which an image is displayed. Reference numeral 120 denotes a drive unit for driving the display unit 110, and causes the display unit 110 to display an image by selectively applying a voltage to the display unit 110 according to image information. Reference numeral 130 denotes an antenna unit for receiving instruction information transmitted from the control device 300. The driving unit 120 applies a voltage based on the content of the instruction information received via the antenna unit 130 to the display unit 110.

Next, the configuration of the display unit 110 of the display medium 100 will be described in more detail with reference to FIG.
FIG. 2 is a diagram showing a part of a longitudinal sectional view of the display unit 110. As shown in the figure, the display unit 110 includes a display layer 110A that forms an image and a sealing layer 110B that is made of a material such as a film material and seals the display layer 110A. In the display layer 110A, 111a and 111b are transparent ITO (indium tin oxide film) substrates, and the ITO substrate 111a and the ITO substrate 111b are provided to face each other with a minute interval. A plurality of line electrodes are formed on the ITO substrates 111a and 111b. Reference numeral 112 denotes a gap member for partitioning the ITO substrate 111a and the ITO substrate 111b into a plurality of sections. In one section divided by the gap member 112, one pixel of the display image is expressed.

  In FIG. 2, only two sections separated by the three gap members 112 are illustrated. However, in practice, the display unit 110 has a plurality of sections separated by a large number of gap members 112 connected to each other. Configured.

  Next, 113B is black particles such as toner used in a copying machine, and 113W is white particles such as titanium oxide. The black particles 113B and the white particles 113W are charged with opposite polarities and sealed between the ITO substrate 111a and the ITO substrate 111b. The driving unit 120 of the display medium 100 applies a voltage to the ITO substrate 111a and the ITO substrate 111b to cause an electric field to act between the ITO substrate 111a and the ITO substrate 111b. Due to the electric field, the black particles 113B and the white particles 113W move to separate ITO substrates 111a or 111b, thereby forming an image.

  Reference numerals 200La and 200Lb denote wireless light amount sensors provided on the sealing layer 110B below the ITO substrate 111b in order to measure the amount of light applied to the display unit 110. These light quantity sensors 200La and 200Lb are provided for each pixel of the image to be displayed (each section divided by the gap member 112), and the light quantity can be measured for each pixel. In FIG. 2, only two light quantity sensors 200La and 200Lb are shown, but in reality, two or more light quantity sensors are provided for each section.

  When the light quantity sensors 200La and 200Lb receive a predetermined radio wave signal, the light quantity sensors 200La and 200Lb transmit radio wave signals indicating the detected light quantity as response signals of the received radio wave signals. Since the structures of the light quantity sensors 200La and 200Lb will be described in detail later, the detailed description thereof is omitted here. By providing the light quantity sensors 200La and 200Lb on the display medium 100, it is possible to measure the light quantity irradiated on the display medium 100. In the following description, when it is not necessary to distinguish the light quantity sensors 200La and 200Lb, the light quantity sensors 200La and 200Lb are referred to as “light quantity sensor 200L” for convenience of explanation.

Next, the configuration of the control device 300 shown in FIG. 1 will be described with reference to FIG.
FIG. 3 is a block diagram illustrating an example of the overall configuration of the control device 300. The control device 300 is a device that controls the driving voltage of the display medium 100 based on a radio wave signal output from the light amount sensor 200L provided in the display medium 100. In the figure, reference numeral 310 denotes a control unit including an arithmetic device such as a CPU. A storage unit 320 includes a memory such as a ROM (Read Only Memory), and stores a program for operating each unit of the control device 300. A RAM (Random Access Memory) 350 is used as a work area when the control unit 310 executes the program. The control unit 310 of the control device 300 controls each unit of the control device 300 by reading and executing the computer program stored in the storage unit 320.

  Further, the storage unit 320 stores a table (or a calculation formula) for calculating a value indicating the light amount based on the result detected by the light amount sensor 200L. Based on this table, control unit 310 calculates a value indicating the light amount from the change in the frequency of the radio signal received from light amount sensor 200L.

  Reference numeral 330 denotes a sensor communication unit including an antenna or the like that transmits a radio signal to the light quantity sensor 200L and receives a radio signal transmitted from the light quantity sensor 200L. Reference numeral 340 denotes a wireless communication unit including an antenna or the like for performing wireless communication such as a wireless LAN. The control device 300 transmits drive voltage instruction information to the display medium 100 via the wireless communication unit 340.

(1-2) Operation Next, a series of operations of the system according to the present embodiment will be described with reference to FIG. In this operation, a series of operations for measuring the light amount of the display medium 100 at a predetermined timing and controlling the drive voltage according to the measurement result will be described.
FIG. 4 is a flowchart showing a drive voltage control process performed by the control unit 310 of the control device 300. First, the control unit 310 transmits a light amount measurement start instruction to start measurement of the light amount to the display medium 100 (step S1).

  When the drive unit 120 of the display medium 100 receives the light amount measurement start instruction via the antenna unit 130, the drive unit 120 controls the frequency and voltage of the drive signal based on the content of the instruction. By this control, as shown in FIG. 5, the black particles 113B and the white particles 113W are brought closer to the gap member 112 side. Since the ITO substrate 111a and the ITO substrate 111b are transparent, the external light L from above passes through the ITO substrate 111a and the ITO substrate 111b and is irradiated to the light amount sensor 200L, thereby measuring the light amount by the light amount sensor 200L. It becomes possible.

  Subsequently, the control unit 310 of the control device 300 transmits a predetermined radio wave signal to the plurality of light quantity sensors 200L provided in the display medium 100 (step S2). When the light quantity sensor 200L provided in the display medium 100 receives a radio wave signal, the light quantity sensor 200L transmits a radio wave signal indicating the detected temperature as a response signal of the received radio wave signal. When receiving the radio signal from the light amount sensor 200L via the sensor communication unit 330, the control unit 310 of the control device 300 calculates the light amount from the received radio signal (step S3).

Here, the light quantity calculation process shown in step S3 of FIG. 4 will be described in detail with reference to the flowchart of FIG.
FIG. 6 is a flowchart showing a light amount calculation process performed by the control unit 310 of the control device 300. The control unit 310 receives a radio wave signal output from the light amount sensor 200L via the sensor communication unit 330 (step S21). The received radio signal is a radio signal with a different frequency transmitted from the plurality of light quantity sensors 200L. The controller 310 sets a counter (not shown) to “n = 0” (step S22).
The control unit 310 performs BPF (band pass filter) processing for extracting the vicinity of a predetermined frequency (step S23). Subsequently, the light amount measured by the light amount sensor 200L is converted from a table stored in advance in the storage unit 320 (step S24), and the conversion result is stored in the RAM or the like (step S25).

When the process of step S25 is completed, the control unit 310 increments the counter to “n = n + 1” (step S26), and determines whether or not n is equal to or greater than the total number of light quantity sensors 200L (step S27). . In this determination, if the counter value is less than “total number of light quantity sensors 200L” (step S27; No), since the conversion from each sensor is not completed, the processing after step S23 is continued, and the counter value Reaches the “total number of light quantity sensors 200L” (step S27; Yes), the process is terminated assuming that the measurement results for all the light quantity sensors 200L have been calculated.
In this usage example, the measurement result from each wireless sensor 200 can be obtained by identifying the light quantity sensor 200L according to the frequency.

  Returning to the description of FIG. When the light amount calculation process shown in step S3 is completed, the control unit 310 generates drive voltage control instruction information for controlling the drive voltage based on the light amount measured by the light amount sensor 200L. The drive voltage control instruction information generated here is composed of a plurality of “drive parameters”. This drive parameter is information set for each section (each pixel of the displayed image) divided by the gap member 112 of the display medium 100, and is information indicating the control content of the drive voltage for each section. The drive unit 120 of the display medium 100 applies a voltage to each section based on the control content indicated by the drive parameter corresponding to the section.

  The controller 310 sets a counter (not shown) to “i = 0” (step S4). Subsequently, the drive parameter value is calculated based on the light amount value measured by the light amount sensor 200L (step S5). Thereafter, the control unit 310 increments the counter to “i = i + 1” (step S6), and determines whether i is equal to or greater than the total number of partitions (step S7). In this determination, if the counter value is less than the “total number of sections” (step S7; No), the calculation of the drive parameter values for all the sections has not been completed, so the processing from step S5 is continued. When the counter value reaches “total number of sections” (step S7; Yes), it is assumed that the drive parameter values have been calculated for all the sections, and the drive voltage control instruction includes all the calculated drive parameters. Information is transmitted to the display medium 100 (step S8).

  When receiving the driving voltage control instruction information via the antenna unit 130, the driving unit 120 of the display medium 100 applies a voltage to each section based on the value of the driving parameter included in this information.

Here, an example of the specific drive voltage control content will be described with reference to FIG.
The display medium 100 shown in FIG. 7 is installed outdoors, and the display medium 100 that is shaded on the lower left is illustrated. In the figure, the display unit 110a is irradiated with sunlight, and the display unit 110b is shaded so that it is not irradiated with sunlight. In this case, for the viewer of the display medium 100, the image displayed on the display unit 110a feels high in contrast (difference in brightness), and the display unit 110b not irradiated with sunlight feels low in contrast. Such a difference in contrast occurs particularly noticeably when the display medium 100 is installed outdoors for use as an electronic bulletin board or the like. Therefore, in the region where the measured light quantity is greater than or equal to a predetermined value, the contrast is lowered by lowering the drive voltage, and in the section where the measured light quantity is less than the predetermined value, the contrast is increased by increasing the drive voltage. Make it high. In this way, the contrast of the image displayed on the display unit 110 is made uniform for the viewer by controlling the drive voltage for each section and adjusting the contrast.

  Since the light quantity sensor 200L used in the present embodiment is a wireless sensor that performs communication using radio wave signals, there is no need to connect the control device 300 and the light quantity sensor 200L with a lead wire or the like. For this reason, the light quantity sensor 200L is connected to the display medium 100. Even in the case where the display medium 100 is provided, the display medium 100 can be sealed. Therefore, it is possible to measure the amount of light of the display medium 100 while maintaining waterproofness and moisture proofness even with respect to the display medium 100 in which image quality degradation occurs due to humidity, and thereby various controls according to the measurement results. Can be done.

  Moreover, since the light quantity for each pixel can be measured by providing the light quantity sensor 200L for each pixel of the displayed image (for each section divided by the gap member 112), the density of detection points can be increased, As a result, the detection accuracy can be increased.

  Conventionally, there is only a method for capturing contrast with a remote camera or the like from the outside as a method for detecting the contrast of an image, and there has been a problem of the installation location of the camera, but the wireless light quantity sensor 200L is used for the display medium 100. By being built in, the contrast of the image displayed on the display medium 100 can be detected without using a remote camera or the like, and the contrast can be adjusted based on the detection result. .

(2) Second Embodiment Next, a second embodiment of the present invention will be described with reference to the drawings.
(2-1) Configuration First, the overall configuration of a system according to the second embodiment of the present invention will be described with reference to FIG. In the following description, the same components and processes as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  The display medium 400 shown in FIG. 8 is different from the display medium 100 according to the first embodiment shown in FIG. 1 in that a measurement region 410d is provided around the display unit, and a light amount sensor is provided in the display unit. 200L is not provided. The measurement region 410d is provided for measuring the charge amount between the ITO substrate 111a and the ITO substrate 111b of the display unit 410.

  FIG. 9 is a diagram showing a part of a longitudinal sectional view of the display unit 410. In the figure, reference numeral 200E denotes a wireless charge amount sensor sealed in the measurement area 410d for measuring the charge amount. The charge amount sensor 200E is sealed and provided for each section partitioned by the gap member 112 of the measurement region 410d, and can measure the charge amount for each section. In FIG. 9, only one charge amount sensor 200E is shown, but actually, a plurality of charge amount sensors are provided for each section of the measurement region 410d. When receiving a predetermined radio signal, the charge amount sensor 200E transmits a radio signal indicating the detected charge amount as a response signal of the received radio signal. Since the structure of the charge amount sensor 200E will be described later in detail, the detailed description thereof is omitted here. By providing the charge amount sensor 200E in the measurement region 410d of the display medium 400, the charge amount in the measurement region 410d can be measured.

(2-2) Operation Next, a series of operations of the system according to the present embodiment will be described with reference to the flowchart of FIG.
FIG. 10 is a flowchart illustrating a drive voltage control process performed by the control unit 310 of the control device 300. First, the control unit 310 of the control device 300 transmits a predetermined radio signal to the charge amount sensor 200E provided in the display medium 400 (step S31). When receiving the radio signal, the charge amount sensor 200E provided in the display medium 400 transmits a radio signal indicating the detected charge amount as a response signal of the received radio signal.

  When receiving the radio signal from the charge amount sensor 200E via the sensor communication unit 330, the control unit 310 of the control device 300 calculates the charge amount from the received radio signal (step S32). This charge amount calculation process is performed in the same manner as the light amount calculation process in the first embodiment. Specifically, the charge amount conversion process is performed instead of the light amount conversion process (step S24 in FIG. 6) in the light amount calculation process shown in the flowchart of FIG. Since the conversion process is the same as the process shown in FIG. 6, the description thereof is omitted here.

  Subsequently, the control unit 310 determines whether or not the charge amount of the entire display unit 410 is decreased based on the charge amount measured by the charge amount sensor 200E (S33). The amount of charge between the ITO substrate 111a and the ITO substrate 111b of the display unit 410 decreases as time elapses, and image quality deterioration occurs when the amount of charge decreases. Therefore, it is possible to determine whether or not image quality deterioration has occurred by determining whether or not the charge amount has decreased. This determination may be made, for example, by calculating an average value of the measured charge amount and determining whether the average value is equal to or less than a predetermined value. When it is determined that the charge amount has decreased (step S33; Yes), an instruction to instruct a process of applying a voltage again (hereinafter referred to as a refresh process) in order to increase the decreased charge amount Information is transmitted to the display medium 400 (step S34).

  When receiving the instruction information, the driving unit 120 of the display medium 400 performs the above-described refresh process. Even when the charge amount of the display unit 410 decreases and the image quality deteriorates due to the passage of time, the charge amount is increased again by detecting the image quality deterioration and performing a refresh process. Accordingly, it is possible to solve the problem of image quality degradation.

  Subsequently, the control unit 310 generates drive voltage control instruction information for controlling the drive voltage based on the charge amount measured by the charge amount sensor 200E. First, the control unit 310 sets a counter (not shown) to “i = 0” (step S35). Subsequently, a drive parameter value is calculated based on the charge amount value measured by the charge amount sensor 200E (step S36). Thereafter, the control unit 310 increments the counter to “i = i + 1” (step S37), and determines whether i is equal to or greater than the total number of partitions (step S38). In this determination, if the counter value is less than the “total number of sections” (step S38; No), the calculation of the drive parameter values for all the sections has not been completed, so the processing from step S36 is continued. When the counter value reaches “total number of sections” (step S38; Yes), it is assumed that the drive parameter values have been calculated for all sections, and the drive voltage control instruction includes all the calculated drive parameters. Information is transmitted to the display medium 400 (step S39).

  When receiving the drive voltage control instruction information via the antenna unit 130, the drive unit 120 of the display medium 400 applies a voltage to each section based on the value of the drive parameter included in this information.

  Since the amount of charge between the ITO substrate 111a and the ITO substrate 111b of the display unit 410 decreases due to the influence of humidity, it is necessary to seal the inside in order to maintain waterproofness and moistureproofness. For this reason, it has been difficult to measure the charge amount in the past, but the charge amount sensor 200E used in the present embodiment is a wireless sensor that performs communication using radio wave signals. Therefore, even when the charge amount sensor 200E is provided on the display medium 400, the display medium 400 can be sealed. Therefore, the charge amount of the display medium 400 can be measured while maintaining waterproofness and moisture proofness even for the display medium 400 in which image quality deterioration occurs due to humidity, and thereby various controls according to the measurement results. Can be performed.

  Further, even when the charge amount of the display unit 410 decreases due to the passage of time and image quality deterioration occurs, the charge amount is again set by detecting the image quality deterioration and performing a refresh process. Thus, the problem of image quality degradation can be solved.

(3) Third Embodiment Next, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 11 is a diagram showing a part of a vertical sectional view of the display unit 510 of the display medium 500 according to the present embodiment. The display unit 510 of the display medium 500 illustrated in FIG. 11 is different from the display unit 410 of the display medium 400 according to the second embodiment illustrated in FIG. 9 in that the charge amount sensor 200E is not provided and the light amount sensor. 200L and a light intake part are provided. The other constituent elements are the same as those shown in FIG. 9, and thus the same reference numerals are given and description thereof is omitted.

  In FIG. 11, reference numeral 514 denotes a light intake unit provided on the top of the ITO substrate 111a. A light amount sensor 200 </ b> Lc for measuring the amount of reflected light from the display unit 510 is provided above the light capturing unit 514. The external light L from the upper part is reflected by the black particles 113B or the white particles 113W. The amount of reflected light can be measured by the light amount sensor 200Lc. In FIG. 11, only one light quantity sensor 200Lc is illustrated, but actually, a plurality of light quantity sensors are provided for each section of the measurement region 410d.

  Based on the amount of reflected light detected by the light amount sensor 200 </ b> Lc provided in the display medium 500, the control unit 310 of the control device 300 displays instruction information indicating a drive voltage control instruction and a refresh processing instruction on the display medium 500. The drive unit 120 of the display medium 500 performs drive voltage control processing and refresh processing based on the received instruction information. These processes are performed in the same manner as the drive voltage control process shown in the second embodiment. Specifically, a light amount calculation process is performed instead of the charge amount calculation process shown in step S32 of FIG. Moreover, about the process which determines whether the charge amount of step S33 has fallen, it is determined whether the charge amount has fallen based on the magnitude | size of a light quantity. The other processes are the same as the processes shown in FIG. 10, and thus the description thereof is omitted here.

  Since the light amount sensor 200Lc is a wireless sensor that performs communication using radio signals, it is not necessary to connect the control device 300 and the light amount sensor 200Lc with a lead wire or the like. For this reason, the light amount sensor 200Lc is provided in the display medium 500. Even so, the display medium 500 can be sealed. Therefore, even if the display medium 500 is subject to image quality deterioration due to humidity, the amount of reflected light from the display medium 500 can be measured while maintaining waterproofness and moistureproofness. It is possible to perform various controls according to the above.

  Conventionally, the only way to detect the contrast of an image is to capture the contrast with a remote camera or the like from the outside, and there has been a problem such as the installation location of the camera, but the reflected light is measured by the wireless light quantity sensor 200L. By doing so, the contrast of the image displayed on the display medium 100 can be detected without using a remote camera or the like, and the contrast can be adjusted based on the detection result.

(4) Modification Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and can be implemented in various other forms. An example is shown below.

(4-1)
In the embodiment described above, the display medium that forms the image by moving the colored particles by applying a voltage is used. However, the configuration of the display medium is not limited to this, and the present invention deteriorates the image quality due to humidity. The present invention can be suitably implemented for any display medium as long as the display medium generates the above.

(4-2)
In the first embodiment described above, the light amount sensor is used as the wireless sensor provided on the display medium. However, the wireless sensor provided on the display medium is not limited to this. For example, the temperature for detecting the temperature of the display medium is used. Any wireless sensor may be used as long as it is a wireless sensor that can suitably detect an environmental state around the display medium, such as a sensor or a humidity sensor that detects humidity. For example, when a temperature sensor is used as a wireless sensor, the temperature of each pixel of the display medium (each section divided by the gap member 112) can be measured, and various controls can be performed according to the measurement result. Become.

  In the first embodiment described above, the wireless sensor is provided for each pixel of the display medium (for each section divided by the gap member 112). However, for example, as shown in FIG. One wireless sensor 200 may be provided in the section). For a display medium with a low resolution, one wireless sensor may be provided for one pixel, and for a display medium with a high resolution, one wireless sensor may be provided for a plurality of pixels.

  In the above-described embodiment, one type of wireless sensor (for example, a light amount sensor) is provided on the display medium. However, for example, a plurality of wireless sensors such as a charge amount sensor and a light amount sensor may be provided. By providing a plurality of wireless sensors, it is possible to measure a plurality of types of physical quantities, thereby increasing the overall detection accuracy.

(4-3)
In the above embodiment, the wireless sensors have different frequencies, and the wireless sensors are uniquely identified by determining the frequencies. However, the wireless sensor identification method is not limited to this. Any method can be used as long as it can identify the response signal of the wireless sensor.

(5) Structure and operation of the wireless sensor 200 Finally, the light amount sensor 200L, the charge amount sensor 200E used in the present embodiment, and the temperature sensor and humidity sensor described in the modification (hereinafter collectively referred to as the wireless sensor 200) An example of the configuration and operation will be described below. Note that the configuration of the wireless sensor 200 is not limited to this, and any configuration may be used as long as it can suitably detect the environmental state (light quantity, charge amount, etc.) around the display medium 100.

(5-1) Configuration of Wireless Sensor 200 First, the configuration of the wireless sensor 200 used in the present embodiment will be described with reference to FIG.
FIG. 13 is a diagram showing a configuration of the wireless sensor 200 according to the embodiment of the present invention. The wireless sensor 200 includes a substrate 1 serving as a base, a dielectric thin film 2 formed on the substrate 1 via an oxide film 1A and propagating a surface acoustic wave (SAW), and a dielectric thin film. A pair of interdigital transducers (IDT) 3A and 3B, which are formed on the substrate 2 and convert the electrical signal into a surface acoustic wave or a surface acoustic wave into an electrical signal, and the pair of comb electrodes Antennas 4A and 4B serving as transmission / reception units connected to one of 3A and 3B via impedance matching units 5A and 5B and transmitting and receiving radio signals to / from an external transmitter / receiver, and a pair of comb-shaped electrodes 3A , 3B and ground electrodes 7 formed on the back surface of the substrate 1 and connected to the grounds 6A, 6B through through holes (not shown). That.

The frequency of the surface acoustic wave in the wireless sensor 200 is set by the shapes of the comb electrodes 3A and 3B and the impedance matching portions 5A and 5B.
The material of the substrate 1 includes a single semiconductor such as Si, Ge, and diamond, glass, AlAs, AlSb, AIP, GaAs, GaSb, InP, InAs, InSb, AlGaP, AlLnP, AlGaAs, AlInAs, AlAsSb, GaInAs, GaInSb, and GaAsSb. III-V compound semiconductors such as InAsSb, II-VI compound semiconductors such as ZnS, ZnSe, ZnTe, CaSe, CdTe, HgSe, HgTe, and CdS, and Nb as a conductive or semiconductive single crystal substrate. , La etc. doped SrTiO ₃ , Al doped ZnO, In ₂ O ₃ , RuO ₂ , BaPbO ₃ , SrRuO ₃ , YBa ₂ Cu ₂ O _7-X , SrVO ₃ , LaNiO ₃ , La _0.5 Sr _0.5 CoO _{3 , ZnGa 2 O 4, CdGa 2} O 4, MgTiO 4. Examples include oxides such as MgTi ₂ O ₄ or metals such as Pb, Pt, Al, Au, and Ag. From the viewpoint of compatibility with existing semiconductor processes and cost, materials such as Si, GaAs, and glass are used. It is preferable to use it.

The dielectric thin film _{2, SiO 2, SrTiO 3,} BaTiO 3, BaZrO 2, LaAlO 3, ZrO 2, Y 2 O 3 8% -ZrO 2, MGO, MgAl 2 O 4, LiNbO 3, LiTaO 3, AlVO _3, oxides such ZnO, as perovskite ABO ₃ type _{BaTiO 3, PbTiO 3, Pb 1} -X La X (Zr y Ti 1-y) 1-X / 4 O 3 (x, the value of y PZT, PLT, PLZT), Pb (Mg _1/3 Nb _2/3 ) O ₃ , KNbO _{3 and} other tetragonal, orthorhombic or pseudocubic materials, suspected ilmenite structures such as LiNbO ₃ and LiTaO ₃ Sr _X Ba _{1 -X} Nb ₂ O ₆ , Pb _X Ba _X Nb ₂ O _6, etc. may be mentioned as representative ferroelectrics or tungsten bronze type. In addition, Bi ₄ Ti ₃ O ₁₂ , Pb ₂ KNb ₅ O ₁₅ , K ₃ Li ₂ Nb ₅ O ₁₅ , and the ferroelectric substitution dielectrics listed above are selected. Further, an ABO ₃ type perovskite oxide containing lead is preferably used. In particular, among these materials, materials such as LiNbO ₃ , LiTaO ₃ , and ZnO are more preferable because of remarkable changes in the surface velocity of the surface acoustic wave, the piezoelectric constant, and the like. The thickness of the dielectric thin film 2 is appropriately selected according to the purpose, but is usually set between 0.1 μm and 10 μm.

  The comb electrodes 3A and 3B, the antennas 4A and 4B, the impedance matching portions 5A and 5B, and the grounds 6A and 6B are integrally formed by a conductive pattern. As a material of this conductive pattern, metals such as Ti, Cr, Cu, W, Ni, Ta, Ga, In, Al, Pb, Pt, Au, and Ag, or Ti—Al, Al—Cu, Ti—N, An alloy such as Ni—Cr is preferably laminated in a single layer or a multilayer structure of two or more layers, and Au, Ti, W, Al, and Cu are particularly preferable as the metal. Moreover, it is preferable that the film thickness of this metal layer shall be 1 nm or more and less than 10 micrometers.

(5-2) Basic Operation of Wireless Sensor 200 Next, the basic operation of the wireless sensor 200 will be described with reference to FIG. In the plan view of the wireless sensor 200 shown in FIG. 13A, for the sake of convenience, it is assumed that the signal moves from the left side to the right side of the drawing, but the signal flow is not actually directional. .

  The wireless sensor 200 exchanges radio signals with external transmitters and receivers. The radio wave signal transmitted from the transmitter is received by the antenna 4A, and the comb electrode 3A excites the dielectric thin film 2 by this signal to generate mechanical vibration. This mechanical vibration generates a surface acoustic wave on the surface of the dielectric thin film 2. The surface acoustic wave moves from the comb-shaped electrode 3A toward the comb-shaped electrode 3B, and the surface acoustic wave that has reached the comb-shaped electrode 3B is converted into an electric signal by the comb-shaped electrode 3B and passes through the antenna 4B. Sent. The receiver receives a radio signal from the wireless sensor 200.

  The surface acoustic wave generated on the surface of the dielectric thin film 2 changes its attributes such as amplitude, phase difference, frequency, and the like due to changes in physical quantities (pressure, light quantity, etc.) applied to the dielectric thin film 2. The change in the surface acoustic wave is received as an electric signal by the receiver, and the change in the attribute in the electric signal is analyzed in the receiver. As a result, the physical quantity applied to the wireless sensor 200 can be measured on the receiver side.

(5-3) Response to Multiple Wireless Sensors 200 The wireless sensor corresponding to one frequency has been described above. Next, a wireless sensor capable of supporting multiple frequencies will be described.
As shown in FIG. 14, in the wireless sensor 200 ′ in which the comb-shaped electrodes 3 </ b> A- 1, 3 </ b> B- 1... 3 </ b> A- 4, 3 </ b> B- 4 having different shapes are formed, A surface acoustic wave corresponding to the frequency is generated on the dielectric thin film 2.

For example, the frequency of the surface acoustic wave set by the comb-shaped electrodes 3A-1 and 3B-1 and the impedance matching units 5A and 5B is set by f1, and the comb-shaped electrodes 3A-2 and 3B-2 and the impedance matching units 5A and 5B are set. The frequency of the surface acoustic wave to be generated is f2, the frequency of the surface acoustic waves set by the comb electrodes 3A-3 and 3B-3 and the impedance matching units 5A and 5B is f3, the comb electrodes 3A-4 and 3B-4 and The frequency of the surface acoustic wave set by the impedance matching units 5A and 5B is assumed to be f4.
In FIG. 14, the illustration of the ground and the ground electrode is omitted.

  Here, when a radio wave signal having a frequency f1 is transmitted from an external transmitter, the electrode 3A-1 corresponding to the frequency f1 generates mechanical vibration in the comb-shaped electrode 3A, and the dielectric thin film 2 is generated by this mechanical vibration. Surface acoustic waves are generated above. This surface acoustic wave is transmitted to the electrode 3B-1. The attribute of the surface acoustic wave transmitted to the electrode 3B-1 changes under the influence of a physical quantity. On the other hand, since the other comb-shaped electrodes 3A-2, 3B-2 to 3A-4, 3B-4 are not tuned to the frequency f1, generation of surface acoustic waves and transmission of radio signals based thereon are performed. Absent. That is, these comb-shaped electrodes 3A-2, 3B-2 to 3A-4, 3B-4 are set to be tuned to frequencies f2, f3, f4, respectively. When transmitted to the sensor 200 ', a surface acoustic wave is transmitted through a path of comb-shaped electrodes 3A-2 → 3B-2, and a radio signal corresponding to the surface acoustic wave is output via the antenna 4B.

Similarly, when a radio signal having a frequency f3 is transmitted to the wireless sensor 200 ′, a surface acoustic wave is transmitted through the path of the comb-shaped electrodes 3A-3 → 3B-3 and output via the antenna 4B. When the radio signal of f4 is transmitted to the wireless sensor 200 ′, the surface acoustic wave is transmitted through the path of the comb-shaped electrodes 3A-4 → 3B-4 and is output via the antenna 4B.
Therefore, if radio waves are transmitted to the wireless sensor 200 ′ in the order of the frequencies f1, f2, f3, and f4, response signals corresponding to these can be obtained. In this case, the change band of the signal output from the comb-shaped electrodes 3B-1, 3B-2, 3B-3, 3B-4 (output side) (the width of change due to the physical quantity) should be set so as not to overlap. For example, even if the frequencies f1 to f4 are simultaneously output to the wireless sensor 200 ′, the four signals output as response signals can be separated and analyzed.

  Here, a specific operation of the wireless sensor 200 used in the above-described embodiment of the present invention will be described. If the four wireless sensors 200 provided on the display medium 100 are wireless sensors 200-1, 200-2, 200-3, 200-4, specifically, the wireless sensor 200 has a surface acoustic wave frequency. Since the shape is set in the shape of the comb-shaped electrodes 3A and 3B, the wireless sensor 200-1 is formed with the comb-shaped electrodes 3A-1 and 3B-1 of the wireless sensor 200 'shown in FIG. 2 includes comb-shaped electrodes 3A-2 and 3B-2 of the wireless sensor 200 ', and the wireless sensor 200-3 includes comb-shaped electrodes 3A-3 and 3B-3 of the wireless sensor 200'. Assume that the comb-shaped electrodes 3A-4 and 3B-4 of the wireless sensor 200 ′ are formed on 200-4. Thereby, the frequency of the surface acoustic wave generated in the dielectric thin film of the wireless sensors 200-1 to 200-4 is f1, wireless sensor 200-2 is f2, wireless sensor 200-3 is f3, The wireless sensor 200-4 becomes f4. That is, the wireless sensors 200-1 to 200-4 are specified by the frequencies f1 to f4 of the received radio signal.

  The radio signal with the frequency f1 is measured by the wireless sensor 200-1, the radio signal with the frequency f2 is measured with the wireless sensor 200-2, and the radio signal with the frequency f3 is measured with the wireless sensor 200-3. The radio signal can be measured by the wireless sensor 200-4.

  The wireless sensors 200-1, 200-2, 200-3, and 200-4 (hereinafter collectively referred to as the wireless sensor 200) receive individual radio signals from the sensor communication unit 330 of the control device 300 and receive individual comb shapes. A surface acoustic wave having a frequency set by the electrode is generated on the dielectric thin film 2, and the frequency of the surface acoustic wave is changed according to the physical quantity, and a signal having a frequency corresponding to the change in the physical quantity is directed to the sensor communication unit 330. Send. And the control part 310 of the control apparatus 300 analyzes the radio wave signal received via the sensor communication part 330, and obtains the physical quantity around the position where each sensor was installed.

  As described above, in the wireless sensor 200, the surface acoustic wave frequency is set in the shape of the comb-shaped electrodes 3A and 3B. In the wireless sensor 200-1 used in this operation example, comb-shaped electrodes 3A-1 and 3B-1 of the wireless sensor 200 'shown in FIG. 14 are formed, and the wireless sensor 200-2 includes the wireless sensor 200'. Comb electrodes 3A-2 and 3B-2 are formed, the wireless sensor 200-3 is formed with comb electrodes 3A-3 and 3B-3 of the wireless sensor 200 ', and the wireless sensor 200-4 is wireless sensor 200. 'Comb-shaped electrodes 3A-4 and 3B-4 are formed. Accordingly, the frequency of the surface acoustic wave generated in the dielectric thin film of the wireless sensor 200 is f1 for the wireless sensor 200-1, f2 for the wireless sensor 200-2, f3 for the wireless sensor 200-3, and the wireless sensor 200-4. f4. That is, the wireless sensors 200-1 to 200-4 are specified by the frequencies f1 to f4 of the radio waves received by the wireless sensor 200.

The control unit 310 transmits a radio wave signal that is a combination of rectangular waves of frequencies f1, f2, f3, and f4 via the sensor communication unit 330. In addition, when receiving the radio signal from the wireless sensor 200, the control unit 310 digitizes the received radio signal and performs analysis / calculation based on the digitized information.
Note that the waveform transmitted to the wireless sensor is not limited to a rectangular wave, and an arbitrary waveform such as a three-string wave or a triangular wave may be used as long as measurement can be performed.

(5-4) Configuration of Temperature Sensor Next, a case where a wireless sensor is used as a temperature sensor will be described. In order to use as a temperature sensor, LiNbO ₃ is used as the material of the dielectric thin film 2 shown in FIG. This LiNbO ₃ crystal is a material whose surface acoustic wave propagation speed changes sensitively to temperature changes, and its temperature coefficient is about 75 × 10 ⁻⁶ / ° C. This change in the propagation speed at the temperature changes the frequency of the surface acoustic wave. For example, in the experiment, a result is obtained in which the frequency changes by about 0.2 to 0.3% with respect to the center frequency f0 of the surface acoustic wave when the temperature changes by about 100 ° C.

(5-5) Configuration of Light Sensor Next, a case where a wireless sensor is used as a light sensor will be described.
FIG. 15 shows the configuration of the light quantity sensor 200L. The configuration of the light quantity sensor 200L shown in FIG. 15 is different from the configuration of the wireless sensor 200 shown in FIG. 13 in that an impedance converter 49 and a light receiving element (for example, a photodiode) 48 are provided on one of the comb electrodes 3B. It is a point provided. This light quantity sensor 200L uses LiTaO ₃ as the material of the dielectric thin film 2. This LiTaO ₃ crystal is a material whose surface acoustic wave propagation velocity has little change with respect to temperature change, and its temperature coefficient is about 18.0 × 10 ⁻⁶ / ° C. The temperature coefficient of the LiNbO ₃ crystal is as small as about 1/4, and the change rate of the surface acoustic wave is about 0.005% with respect to a temperature change of 10 ° C.

  When light having a certain illuminance (for example, 1000 lx) is applied to the light receiving element 48, the impedance of the light receiving element 48 changes corresponding to this light quantity, and this impedance change matches impedance of the comb electrode 3B. It is transmitted to the comb-shaped electrode 3B through the container 49. Here, the impedance change in the comb electrode 3B changes the reflection intensity when the surface acoustic wave propagated from the input comb electrode 3A is reflected by the comb electrode 3B. The comb-shaped electrode 3A receives the reflected surface acoustic wave again and transmits it to the outside as an electromagnetic wave. In the light quantity sensor 200L configured in this manner, the light intensity sensor changes by about 0.1% with respect to the standard electric field strength.

(5-6) Configuration of Charge Quantity Sensor Next, a case where a wireless sensor is used as the charge quantity sensor will be described.
FIG. 16 shows the configuration of the charge amount sensor 200E. The configuration of the charge amount sensor 200E shown in FIG. 16 is different from the configuration of the wireless sensor 200 shown in FIG. 13 in that an impedance converter 51 and a coil 52 are wound around one of the comb electrodes 3B as shown in the figure. This is that a ferrite core 53 is provided. In order to use this as the charge amount sensor 200E, LiTaO ₃ is used as the material of the dielectric thin film 2 shown in FIG.

  In the above-described embodiment, the magnetic field transmitted to the ferrite core 53 of the charge amount sensor 200E changes corresponding to the electric field generated by applying a voltage to the display unit 410 of the display medium 400. The impedance of the coil 52 is changed. This change in impedance is transmitted to the comb electrode 3B through the impedance converter 51 that matches the impedance of the comb electrode 3B, and when the surface acoustic wave propagated from the input comb electrode 3A is reflected by the comb electrode 3B. Change the reflection intensity. When this reflected surface acoustic wave is received again by the comb-shaped electrode 3A and oscillates as an electromagnetic wave, the charge amount sensor 200E operates by changing about 0.1% with respect to the standard electric field strength. This wireless sensor realizes a charge amount sensor in which the intensity of the received signal in the receiver linearly changes in accordance with the change in charge amount.

In the embodiment, as means for identifying each sensor, the frequency and frequency of the surface acoustic waves generated in the dielectric thin film are individually set by changing the shape and size of the comb-shaped electrodes 3A and 3B. It is made to identify. The means for identifying the sensor is not limited to this, and it can also be realized by making the shape and size of the comb electrodes the same and making the separation distance between the comb electrodes different.
Specifically, the time of the surface acoustic wave generated on the dielectric thin film is different by making the separation distance between the comb electrodes different. Focusing on this point, the sensor may be identified by measuring the time from signal transmission of the transmitter to signal reception at the receiver.

1 is a diagram illustrating an overall configuration of a system according to a first embodiment of the present invention. It is a figure which shows a part of longitudinal cross-sectional view of the display part 110 of the embodiment. It is a block diagram which shows the whole structure of the control apparatus 300 of the embodiment. It is a flowchart which shows the drive voltage control process which the control part 310 of the embodiment performs. It is a figure which shows a part of longitudinal cross-sectional view of the display part 110 of the embodiment. It is a flowchart which shows the light quantity calculation process which the control part 310 of the embodiment performs. It is a figure which shows the structure of the display medium 100 of the embodiment. It is a figure which shows the whole structure of the system which concerns on 2nd Embodiment of this invention. It is a figure which shows a part of longitudinal cross-sectional view of the display part 410 of the embodiment. It is a flowchart which shows the drive voltage control process which the control part 310 of the embodiment performs. It is a figure which shows a part of longitudinal cross-sectional view of the display part 110 which concerns on 3rd Embodiment of this invention. It is a figure which shows a part of longitudinal cross-sectional view of the display part which concerns on the modification of this invention. 2 is a diagram showing a basic structure of a wireless sensor 200. FIG. It is a figure which shows the structure of the wireless sensor 200 corresponding to a some frequency. It is a figure which shows the structure of the light quantity sensor 200L. It is a figure which shows the structure of the charge amount sensor 200E. It is a figure which shows the whole structure of the display medium based on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Display medium, 110 ... Display part, 110A ... Display layer, 110B ... Sealing layer, 120 ... Drive part, 130 ... Antenna part, 111a, 111b ... ITO substrate, 112 ... Gap member, 113B ... Black particle, 113W ... White Particles, 514: Light intake unit, 200E: Charge amount sensor, 200L ... Light quantity sensor, 300 ... Control device, 310 ... Control unit, 320 ... Storage unit, 330 ... Sensor communication unit, 340 ... Wireless communication unit, 350 ... RAM DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Dielectric thin film, 3A, 3B ... Comb-type electrode, 5A, 5B ... Impedance matching part, 4A, 4B ... Antenna, 6A, 6B ... Ground, 7 ... Ground electrode.

Claims (10)

A display medium layer for electrically switching display;
When a predetermined radio wave signal is supplied, wireless measurement means for detecting a physical quantity indicating the surrounding environmental state using it as an energy source, generating and outputting a radio signal having an attribute reflecting the detected physical quantity, and
A display medium comprising: a sealing layer that covers and seals the wireless measurement unit. A display medium layer for electrically switching display;
Wireless measurement means for detecting a physical quantity indicating an ambient environmental condition when a predetermined radio signal is supplied as an energy source, and generating and outputting a radio signal having an attribute reflecting the detected physical quantity ,
The display medium, wherein the wireless measuring means is sealed in the display medium layer. A display medium layer for electrically switching display;
A sealing layer for sealing the display medium layer;
Wireless measurement means for detecting a physical quantity indicating an ambient environmental condition when a predetermined radio signal is supplied as an energy source, and generating and outputting a radio signal having an attribute reflecting the detected physical quantity ,
The display medium according to claim 1, wherein the wireless measuring means is provided exposed to the sealing layer. The display medium according to any one of claims 1 to 3, wherein the display medium layer displays information to be displayed by driving display particles by electrification in a visible state.   The display medium according to claim 1, wherein the physical quantity is at least one of light quantity, charge quantity, temperature, and humidity.   When a predetermined radio signal is supplied, the wireless measurement unit detects a physical quantity indicating an ambient environmental condition using the predetermined radio signal as an energy source, and generates a radio signal having an attribute reflecting the detected physical quantity and identification information. The display medium according to claim 1, further comprising a plurality of the wireless measuring means.   The display medium according to claim 1, further comprising a plurality of types of the wireless measurement units that detect different physical quantities. A display medium control device for controlling the display medium according to claim 1,
Receiving means for receiving a radio signal output from the wireless measuring means;
Calculating means for calculating the physical quantity from the radio signal received by the receiving means;
A display medium control device comprising: drive voltage control means for controlling the drive voltage of the display medium based on the physical quantity calculated by the calculation means. A display medium control device for controlling the display medium according to claim 1,
Receiving means for receiving a radio signal output from the wireless measuring means;
Calculating means for calculating the amount of light from the radio signal received by the receiving means;
A display medium control device comprising: an adjusting unit that adjusts a contrast of an image displayed on the display medium based on the light amount calculated by the calculating unit.   The display medium control device according to claim 8, wherein the physical quantity is at least one of a light quantity, a charge quantity, temperature, and humidity.

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