JP2010186008A - Display device, display method and display program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device, wherein power consumption is reduced and processing time for display rewriting is short and response is good. <P>SOLUTION: In a step S104, a first clock PCK is supplied to an arithmetic processing section 104, and a second clock MCK is converted by a clock conversion section 105 to generate a converted clock CCK, which is supplied to a clock supply block 107. In a step S105, the arithmetic processing section 104 executes a control program in synchronization with the first clock PCK. In a step S108, an electrophoresis display section 4 in each peripheral device is supplied with driving voltage from a driving voltage generation section 181 in synchronization with the converted clock, performing a page rewriting process. In a step S109, supply of the first clock PCK to the arithmetic processing section 104 is stopped, ending the execution of the control program. During this time, the converted clock is supplied to the each peripheral device, and supply of the driving voltage to the electrophoresis display section 4 is continued. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display device including a nonvolatile display unit. Specifically, the present invention relates to a display device and a display method that reduce power consumption of the display device by controlling supply and stop of power to various types of hardware included in the display device.

  Patent Document 1 describes a display device including a non-volatile display unit that maintains display contents even when power supply is stopped. Specifically, a technique for controlling power supply to the main control unit and stop of power supply is disclosed. The main control unit includes a CPU, various storage means, a nonvolatile display unit, and the like. Based on the fact that the operation of the keys provided in the display device has not been performed for a certain period of time, the supply of power to the main control unit is stopped. By shifting to the power saving mode in which the supply of power to the display device is stopped, power consumption is reduced. In the display device described in Patent Literature 1, when a key is operated to rewrite the display on the nonvolatile display unit, power is generally supplied again to the main control unit. After power is supplied to the main control unit, display information is newly read out from storage means such as an SD card and developed in the RAM. An image is displayed on the non-volatile display unit in accordance with the display information expanded in the RAM.

JP 2007-121374 A

  In the display device described in Patent Document 1, a nonvolatile display unit is used. The nonvolatile display unit does not need to supply power in order to maintain display, but needs to supply a driving voltage to rewrite an image. In order to rewrite the image displayed on the non-volatile display unit, the supply and stop of the drive voltage and the voltage value thereof are controlled according to the display information. By controlling the drive voltage supply operation and the like, various displays can be performed by the display medium. The display device described in Patent Literature 1 has a power saving mode. In the power saving mode, the driving voltage is not supplied to the nonvolatile display unit. In order to start the nonvolatile display unit from the power saving mode and newly rewrite the display of the nonvolatile display unit, it is necessary to supply a drive voltage to the nonvolatile display unit. However, the rise until the nonvolatile display unit receives the drive voltage and normally performs the rewrite operation is relatively slow. Therefore, the responsiveness of the display device was bad.

  The present invention has been made to solve the above-described problems. An object of the present invention is to provide a display device that can reduce power consumption and has a short response time for rewriting a display and good response.

  According to the first aspect of the present invention, there is provided a display device having a nonvolatile display unit that rewrites a display when a drive voltage is supplied according to display information and maintains a display when the supply of the drive voltage is stopped. An operation unit operable to instruct various operations of the display device, a nonvolatile program storage unit that stores a control program for controlling the display device, and a control program stored in the program storage unit are executed. Or a program control unit that controls to stop the execution, a drive voltage generation unit that generates the drive voltage, and a first that supplies the drive voltage to the nonvolatile display unit or stops the supply thereof. When the operation unit is operated to rewrite the display of the non-volatile display unit and the voltage control unit that executes control, the voltage control unit is controlled by the first control. From the second mode in which the drive voltage is supplied to the nonvolatile display unit and the program control unit stops executing the control program, the voltage control unit supplies the drive voltage to the nonvolatile display unit by the first control. Is switched to the first mode when the program control unit switches to the first mode in which the program is executed and the display is rewritten according to the display information in the first mode. And a switching unit.

  According to the second aspect of the present invention, the volatile temporary storage unit that temporarily stores the control program stored in the program storage unit, and the control program temporarily stored in the temporary storage unit by the program control unit A clock generator for generating a first clock for execution and a second clock for the voltage control unit to supply the driving voltage by the first control; and supplying power to at least the temporary storage unit Or a power control unit that executes a second control for stopping the supply, wherein the program control unit executes the control program based on the first clock, and the voltage control unit A command for supplying the driving voltage based on two clocks is supplied to the nonvolatile display unit, and the mode switching unit switches from the second mode to the first mode. The power control unit supplies power to at least the temporary storage unit, the clock generation unit generates the first clock and the second clock, and the mode switching unit When the mode is switched to the second mode, the power control unit supplies power to at least the temporary storage unit, and the clock generation unit stops the first clock and generates the second clock It is characterized by doing.

  According to a third aspect of the present invention, the clock generator generates the first clock having a higher frequency than the second clock.

  According to the fourth aspect of the present invention, the information acquisition unit that acquires the display information from the nonvolatile information storage unit that stores the display information that causes the non-volatile display unit to perform a predetermined display, and the program storage unit A volatile temporary storage unit for temporarily storing the control program stored in the information acquisition unit and the display information acquired by the information acquisition unit, and the display information stored in the temporary storage unit when the operation unit is operated And a non-volatile position that stores a storage position where display information related to an image currently displayed on the non-volatile display unit is stored in the information storage unit A storage unit, and the power control unit supplies at least power to the temporary storage unit or stops the supply of the second control, the nonvolatile display unit, and the information acquisition unit. The program storage unit, the temporary storage unit, the display control unit, and the position storage unit are supplied with electric power, or the third control for stopping the supply of electric power is executed. A first mode in which a control unit supplies the drive voltage to the nonvolatile display unit by the first control, supplies power by the second control, and the program control unit executes a control program; The voltage control unit supplies the driving voltage to the nonvolatile display unit by the first control, supplies power by the second control, and the program control unit stops execution of the control program. In the second mode, the power control unit stops supplying the drive voltage to the non-volatile display unit by the first control, stops supplying power by the third control, and The program control unit can switch between the third mode in which the execution of the control program is stopped, and the display control unit is switched from the third mode to the first mode by the mode switching unit. In accordance with the display information acquired from the storage position by the information acquisition unit and stored in the temporary storage unit, a predetermined display is displayed on the non-volatile display unit, and the second mode is switched from the second mode by the mode switching unit. When the mode is switched to the first mode, a predetermined display is displayed on the nonvolatile display unit according to the display information stored in the temporary storage unit.

  According to a fifth aspect of the present invention, the mode switching unit switches to the third mode after a predetermined first time has elapsed since switching to the second mode.

  According to the invention described in claim 6, various operations of the display device having a nonvolatile display unit that rewrites the display when the drive voltage is supplied according to the display information and maintains the display when the supply of the drive voltage is stopped. An operation step for instructing, and a voltage control step for causing the drive voltage generator for generating the drive voltage to supply the drive voltage to the non-volatile display unit, or executing a first control for stopping the supply, Non-volatile for controlling the display device with the driving voltage supplied to the non-volatile display unit by the voltage control step when an instruction is given by the operation step to rewrite the display of the non-volatile display unit From the second mode in which the execution of the control program stored in the program storage unit is stopped, the drive to the nonvolatile display unit by the voltage control step A mode switching step of switching from the first mode to the second mode when the display is rewritten according to the display information in the first mode when the control program is executed in a state where pressure is supplied; And a program control step of executing or stopping the execution of the control program according to the mode switched by the mode switching step.

  According to the seventh aspect of the invention, various operations of the display device having a nonvolatile display unit that rewrites the display when the driving voltage is supplied according to the display information and maintains the display when the supply of the driving voltage is stopped. An operation detecting step for detecting whether or not an operation has been performed for instructing; and a driving voltage generating unit for generating the driving voltage to supply the driving voltage to the nonvolatile display unit or to stop the supply. When a voltage control step for commanding control and an operation for rewriting the display on the non-volatile display unit are detected by the operation detection step, the supply of the drive voltage to the non-volatile display unit is commanded by the voltage control step. From the second mode in which the execution of the control program stored in the non-volatile program storage unit is stopped in order to control the display device in the When the voltage control step switches to the first mode in which the control program is executed in a state where the supply of the drive voltage to the nonvolatile display unit is commanded, and the display is rewritten according to the display information in the first mode, A computer realizes a mode switching step for switching from the first mode to the second mode, and a program control step for executing or stopping the execution of the control program according to the mode switched by the mode switching step. Display program.

  Generally, when power is supplied to the main control unit of the display device, the responsiveness of the display device including display rewriting is good. On the other hand, when the supply of power to the main control unit is stopped, the responsiveness deteriorates, but it is effective in reducing power consumption. In order to simultaneously satisfy the contradiction between the responsiveness of the display device and the reduction in power consumption, the voltage control unit supplies the driving voltage to the non-volatile display unit, or the The first control for stopping the supply is executed. When the operation unit is operated to rewrite the display on the non-volatile display unit, the mode switching unit supplies the drive voltage to the non-volatile display unit by the first control, and the program control unit controls the control program. In the first mode, the voltage control unit switches to the first mode in which the drive voltage is supplied to the nonvolatile display unit by the first control and the program control unit executes the control program from the second mode in which the execution of the program is stopped. When the display is rewritten according to the display information, the first mode is switched to the second mode. Accordingly, the drive voltage for rewriting the image is supplied to the nonvolatile display unit in both the first mode and the second mode. Therefore, the rise time of the display device is shortened. In the second mode, the execution of the control program is stopped. By stopping the execution of the control program, the power consumed by arithmetic processing means such as a CPU is greatly reduced. In a display device using a nonvolatile display unit, supply of power to the main control unit of the display device is stopped. The above-described display device is particularly effective because the ratio of power consumed by arithmetic processing means such as a CPU is large. Therefore, since the control program is not executed, power consumption is reduced. As a result, in the second mode, the power consumption of the display device is reduced, the startup time for rewriting the display is shortened, and the responsiveness for rewriting the display is improved.

  According to the second aspect of the present invention, the clock generation unit includes a first clock for the program control unit to execute the control program temporarily stored in the temporary storage unit, and the voltage control unit uses the first control to drive voltage. And a second clock for supplying. The program control unit executes the control program based on the first clock. The voltage control unit supplies a command for supplying a drive voltage to the nonvolatile display unit based on the second clock. Accordingly, since supply and stop of the drive voltage and execution and stop of the control program are controlled by generation and stop of the first and second clocks, a special hardware other than the clock generator is used to perform these controls. Wear is not necessary. As a result, no power is required to activate special hardware, power consumption is reduced, and responsiveness for rewriting the display is improved.

  According to the invention described in claim 3, the clock generator generates the first clock having a higher frequency than the second clock. The control program performs confirmation processing such as confirmation of activation of the main control unit. In order to increase the rising speed of the display device, the first clock for executing the control program should have a high frequency. The first clock needs to be a clock having a higher frequency than the second clock for supplying the drive voltage. On the other hand, the higher the frequency of the first clock for executing the control program, the greater the power consumption of the device that is driven and controlled by the control program. Therefore, according to the third aspect of the present invention, the first clock is set to a frequency higher than that of the second clock, so that the execution speed of the control program is increased and the control program is stopped when the control program is stopped. This eliminates the power consumption of the device controlled by the control. As a result, the power consumption of the entire display device is reduced and the responsiveness to rewrite the display is improved.

  According to the invention described in claim 4, the display device includes the nonvolatile position storage unit that stores the storage position where the display information currently displayed on the nonvolatile display unit is stored in the information storage unit. The mode switching unit supplies the driving voltage to the nonvolatile display unit by the first control and supplies power by the second control, and the program control unit executes the control program. The first mode, the voltage control unit supplies the driving voltage to the nonvolatile display unit by the first control, supplies power by the second control, and the program control unit controls The second mode in which the program execution is stopped, and the power control unit stops the supply of the driving voltage to the nonvolatile display unit by the first control and stops the supply of power by the third control. In addition, the program control unit can be switched between the third mode in which the execution of the control program is stopped. When the mode switching unit is switched from the third mode to the first mode by the mode switching unit, the display control unit applies a predetermined amount to the nonvolatile display unit according to the display information acquired from the storage position by the information acquisition unit and stored in the temporary storage unit. When the mode is switched from the second mode to the first mode by the mode switching unit, a predetermined display is displayed on the nonvolatile display unit according to the display information stored in the temporary storage unit. The third mode is a mode in which the supply of power to the main control unit of the display device such as the nonvolatile display unit and each storage unit is stopped. Therefore, even in the case of the third mode, the nonvolatile display unit can maintain the display. Further, even when the display device is switched from the third mode to the first mode, the display information is read from the information storage unit based on the storage position stored in the nonvolatile position storage unit. Therefore, display is started in the first mode from the continuation of the image displayed on the non-volatile display unit in the third mode. As a result, the third mode is the most excellent mode for reducing power consumption although the responsiveness is poor. The first mode is the mode with the best response. The second mode is a mode in which power consumption reduction and responsiveness are satisfied to some extent. By switching the mode among the first mode, the second mode, and the third mode, the responsiveness of the display device and the reduction of power consumption are satisfied at the same time. Therefore, the responsiveness for rewriting the display is improved. Even in the third mode, since the display is started from the continuation of the image displayed on the non-volatile display unit, the operability is improved.

  According to the fifth aspect of the present invention, the mode switching unit switches to the third mode after a predetermined first time has elapsed since switching to the second mode. As a result, since the mode of the display device is automatically switched to the third mode with the lowest power consumption, reduction of power consumption is promoted.

  Generally, when power is supplied to the main control unit of the display device, the responsiveness of the display device including display rewriting is good. On the other hand, when the supply of power to the main control unit is stopped, the responsiveness deteriorates, but it is effective in reducing power consumption. In order to simultaneously satisfy the contradictions of the responsiveness of the display device and the reduction in power consumption, according to the invention described in claim 6, the voltage control step causes the drive voltage to be generated in the drive voltage generator that generates the drive voltage. The first control is performed to supply to the sex display unit or to stop the supply. In the mode switching step, when an instruction is given by the operation step to rewrite the display of the non-volatile display unit, the non-volatile mode is used to control the display device in a state where the driving voltage is supplied to the non-volatile display unit by the voltage control step. Switching from the second mode in which the execution of the control program stored in the sex program storage unit is stopped to the first mode in which the control program is executed in a state where the drive voltage is supplied to the nonvolatile display unit by the voltage control step, When the display is rewritten according to the display information in the first mode, the mode is switched from the first mode to the second mode. Accordingly, the drive voltage for rewriting the image is supplied to the nonvolatile display unit in both the first mode and the second mode. Therefore, the rise time of the display device is shortened. In the second mode, the execution of the control program is stopped. By stopping the execution of the control program, the power consumed by arithmetic processing means such as a CPU is greatly reduced. In a display device using a nonvolatile display unit, supply of power to the main control unit of the display device is stopped. The above-described display device is particularly effective because the ratio of power consumed by arithmetic processing means such as a CPU is large. Therefore, since the control program is not executed, power consumption is reduced. As a result, in the second mode, the power consumption of the display device is reduced, the startup time for rewriting the display is shortened, and the responsiveness for rewriting the display is improved.

  Generally, when power is supplied to the main control unit of the display device, the responsiveness of the display device including display rewriting is good. On the other hand, when the supply of power to the main control unit is stopped, the responsiveness deteriorates, but it is effective in reducing power consumption. In order to simultaneously satisfy the contradiction of the responsiveness of the display device and the reduction of power consumption, according to the invention of claim 7, the voltage control step is configured such that the drive voltage is non-volatile in the drive voltage generator that generates the drive voltage. The first control for commanding the supply to the sex display unit or stopping the supply is commanded. In the mode switching step, when an operation for rewriting the display of the non-volatile display unit is detected by the operation detection step, the display device is controlled in a state in which the supply of the drive voltage to the non-volatile display unit is commanded by the voltage control step. From the second mode in which the execution of the control program stored in the nonvolatile program storage unit is stopped, the control program is executed in a state in which the supply of the drive voltage to the nonvolatile display unit is commanded by the voltage control step The mode is switched to the first mode, and when the display is rewritten according to the display information in the first mode, the mode is switched from the first mode to the second mode. Accordingly, the drive voltage for rewriting the image is supplied to the nonvolatile display unit in both the first mode and the second mode. Therefore, the rise time of the display device is shortened. In the second mode, the execution of the control program is stopped. By stopping the execution of the control program, the power consumed by arithmetic processing means such as a CPU is greatly reduced. In a display device using a nonvolatile display unit, supply of power to the main control unit of the display device is stopped. The above-described display device is particularly effective because the ratio of power consumed by arithmetic processing means such as a CPU is large. Therefore, since the control program is not executed, power consumption is reduced. As a result, in the second mode, the power consumption of the display device is reduced, the startup time for rewriting the display is shortened, and the responsiveness for rewriting the display is improved.

1 is an external view of an image display device 1 according to an embodiment. It is a front view of the electrophoretic display part 4 in an embodiment. FIG. 3 is a cross-sectional view in the direction of the arrow along the line A-A ′ of the electrophoretic display unit 4 shown in FIG. 2 is a block diagram showing an electrical configuration of the image display device 1. FIG. It is a functional conceptual diagram which shows the functional structure of CPU10 in embodiment. It is a block diagram which shows the electric constitution of the electric power control part 19 in embodiment. It is a flowchart which shows the main operation | movement in embodiment. It is a flowchart which shows the page rewriting process in embodiment. It is a conceptual diagram which shows the memory | storage state by which display information is memorize | stored in the display information storage area 121 in embodiment. It is a conceptual diagram which shows an example of the memory | storage state in which the display file information and display page information in embodiment are memorize | stored in EEPROM14.

[Embodiment]
Hereinafter, an embodiment in which the present invention is applied to a portable display device including an electrophoretic display unit will be described with reference to the drawings.

<External configuration of embodiment>
FIG. 1 is an external view of a portable image display device 1 according to an embodiment to which the present invention is applied. The image display device 1 of the embodiment is a substantially rectangular parallelepiped. The image display device 1 of this embodiment includes a power switch 2, an electrophoretic display unit 4, two operation keys 5, and operation keys 6. The power of the image display device 1 is turned on or off by the power switch 2. By operating the operation keys 5 and 6, the image displayed on the electrophoretic display unit 4 is rewritten. By operating the operation key 5, an image one page before the image currently displayed on the electrophoretic display unit 4 is displayed. By operating the operation key 6, an image one page after the image currently displayed on the electrophoretic display unit 4 is displayed. The operation keys 5 and 6 of the embodiment are examples of the operation unit of the present invention. The electrophoretic display unit 4 of the embodiment is an example of a nonvolatile display unit of the present invention.

  FIG. 2 is a front view of the electrophoretic display unit 4. FIG. 3 is a cross-sectional view in the direction of the arrow along the line AA ′ of the electrophoretic display unit 4 shown in FIG. Hereinafter, the electrophoretic display unit 4 will be described with reference to FIGS. 2 and 3. For convenience of explanation, FIGS. 2 and 3 show an example in which a monochrome image is displayed by the electrophoretic display unit 4 and the number of pixels of the electrophoretic display unit 4 is 20 (5 × 4). In the present embodiment, one pixel space corresponds to one pixel. Actually, the number of pixels according to need is provided.

  As shown in FIG. 2, the display surface of the electrophoretic display unit 4 is provided with a pixel space 21 for displaying an image. In the embodiment, in order to generate an electric field with respect to the pixel space 21, an electrode is disposed at the same position as the pixel space 21. A peripheral portion where the pixel space 21 is arranged is covered with an upper electrode protective film 61. The upper electrode protective film 61 is formed of a material that can exhibit high transparency, such as polyimide, polyethylene terephthalate, glass, titanium oxide, silicon oxide, and polystyrene. The peripheral portion of the electrophoretic display unit 4 that is not provided with the pixel space 21 is surrounded by a mask unit 40 for concealing it so that the user cannot see it.

  In the image display device 1 according to the embodiment, the directions of the arrows shown in FIG. As shown in FIG. 3, the electrophoretic display unit 4 includes a mask unit 40, a lower substrate 50, an upper substrate 60, a display unit 70, and a partition wall 71. The lower substrate 50 is provided on the lower surface portion of the electrophoretic display unit 4. The upper substrate 60 is disposed to face the lower substrate 50 in the upward direction with the display unit 70 interposed therebetween. The user of the image display device 1 browses an image displayed via the display layer 63 from above in FIG.

  The partition wall 71 is disposed between the lower substrate 50 and the upper substrate 60 and is supported by both substrates. The partition walls 71 are arranged so as to form a large number of pixel spaces 21 by equally dividing the lower substrate 50 into a lattice shape.

  The display unit 70 is configured by filling each pixel space 21 with charged particles 33 a, charged particles 33 b, and a dispersion medium 34. Specifically, a large number of pixel spaces 21 are divided on the lower substrate 50 by a partition wall 71 in a lattice shape. Charged particles 33 a, charged particles 33 b, and dispersion medium 34 are filled in each pixel space 21. As materials for the charged particles 33a and the charged particles 33b, materials that can be charged in the dispersion medium 34 are used. As materials for the charged particles 33a and the charged particles 33b, pigments and dyes made of organic compounds or inorganic compounds, or pigments and dyes wrapped with a synthetic resin are used. In the present embodiment, a mixture of styrene resin and titanium dioxide is used as the material as the charged particles 33a. As the charged particles 33a, particles having an average particle diameter of 5 μm and an amount of titanium dioxide in the particles of 40 wt% are used. As the charged particles 33b, a mixture of styrene resin and carbon black is used. As the charged particles 33b, particles having an average particle diameter of 5 μm and a carbon black amount of 30 wt% in the particles are used. Therefore, the charged particles 33a have a white color tone, and the charged particles 33b have a black color tone. The charged particles 33a and the charged particles 33b are charged so as to be different from each other positively or negatively. In the embodiment, the charged particles 33a are negatively charged and the charged particles 33b are positively charged.

  As the dispersion medium 34, alcohols, hydrocarbons, or silicone oils having high insulating properties and low viscosity are used. In the embodiment, Isopar manufactured by ExxonMobil, which is a paraffinic solvent, is used as the dispersion medium 34. Note that ethanol is added to the dispersion medium 34 as an additive. The charged particles 33a, charged particles 33b, and solvents that occupy each pixel space 21 are as follows. The white charged particles 33a are 7 wt%. The black charged particles 33b are 10 wt%. The solvent 1 is Isopar: 73 wt%. The solvent 2 is ethanol: 10 wt%.

  The lower substrate 50 includes a lower electrode protective film 51, a lower electrode 52, and a housing support part 53.

  The lower electrode protective film 51 is an insulating film formed by applying an insulating material to the upper surface side of the lower electrode 52. The lower electrode protective film 51 is formed of a material having a high insulating effect, such as a resin film such as polyethylene terephthalate or polystyrene, or an inorganic material such as silicon oxide or titanium oxide. In the present embodiment, silicon oxide is used as the lower electrode protective film 51.

  The lower electrode 52 is provided for applying a voltage to the pixel space 21. The lower electrode 52 is disposed in parallel with the upper electrode 62 in order to apply a constant voltage to each of the pixel spaces 21.

  The housing support member 53 is provided on the lower surface side of the lower electrode 52. The housing support part 53 supports the image display device 1 itself.

  The upper substrate 60 includes an upper electrode protective film 61, an upper electrode 62, and a display layer 63. A mask portion 40 is provided on the upper surface of the upper substrate 60 (the surface that does not face the lower substrate 50).

  The upper electrode protective film 61 is an insulating film formed by applying an insulating material to the lower surface side of the upper electrode 62. The upper electrode protective film 61 is made of a highly transparent material such as polyimide, polyethylene terephthalate, glass, titanium oxide, silicon oxide, or polystyrene. In the present embodiment, silicon oxide is used as the material of the upper electrode protective film 61.

  The upper electrode 62 is an electrode for generating an electric field between the upper electrode 62 and the lower electrode 52. In order to apply a predetermined voltage to each of the pixel spaces 21, the pixel space 21 is arranged as a common electric conductor provided with the upper electrode 62. The upper electrode 62 is made of a highly transparent material. In the present embodiment, a transparent electrode made of indium tin oxide (ITO) is used as the upper electrode 62.

  The display layer 63 is formed of a transparent member such as glass, polyethylene terephthalate, polycarbonate, or triacetyl cellulose. The display layer 63 is provided on the upper surface side of the upper electrode 62. The display layer 63 functions as a display screen. As the display layer 63, a flexible glass substrate is used. Since the upper substrate 60 is formed of the above-described highly transparent material, the user can visually recognize the display unit 70 from above the upper substrate 60.

  The mask unit 40 is provided to conceal the peripheral portion of the display unit 70 where the pixel space 21 does not exist so that the user cannot visually recognize it. The mask portion 40 is provided with a constant width along the four sides of the upper substrate 60. As the mask unit 40, a plate-shaped member having a square shape shown in FIG. 3 is used so that the user can visually recognize the display unit 70. As the mask portion 40, a member colored with a synthetic resin such as polyethylene terephthalate is used. Further, an ink layer having an effect equivalent to that of the mask portion 40 may be directly formed on the surface of the display layer 63 with ink or the like. In the present embodiment, polyethylene terephthalate is used as the mask portion 40.

<Electrical Configuration of Embodiment>
FIG. 4 is a block diagram illustrating an electrical configuration of the image display apparatus 1 according to the embodiment. As shown in FIG. 4, the image display device 1 includes a CPU 10 that controls the image display device 1. The CPU 10 includes a vibrator 101, a memory card interface (I / F) 11, a NAND flash memory 13, an EEPROM 14, a RAM 15, a battery 16, a wireless communication unit 17, a display control unit 18, power The control unit 19 and the operation keys 5 and 6 are electrically connected to each other. In order to supply a clock to many peripheral devices connected to the CPU 10, the CPU 10 generates a plurality of clocks having different predetermined frequencies. The generated clock is supplied to a large number of peripheral devices connected to the CPU 10. The frequency of the supplied clock is a frequency suitable for the operation of each peripheral device. A clock with the same frequency may be supplied to different peripheral devices. The memory card I / F 11 is connected to the memory card 12 and reads information from the memory card 12. The CPU 10 constitutes the computer of the embodiment together with storage means such as the memory card 12, the flash memory 13, the EEPROM 14, and the RAM 15. In this embodiment, an SD card (registered trademark) is used as the memory card 12. In the present embodiment, Bluetooth (registered trademark) is used as the wireless communication unit 17.

  The vibrator 101 is connected to the battery 16 via the CPU 10. When power is supplied from the battery 16 to the CPU 10, power is also supplied to the vibrator 101. In accordance with a command from the CPU 10, the vibrator 101 oscillates a predetermined reference clock. The reference clock oscillated by the vibrator 101 is supplied to the CPU 10.

  FIG. 5 is a functional conceptual diagram showing various functions of the CPU 10 of the embodiment in blocks. The CPU 10 includes a first clock generation unit 102, a second clock generation unit 103, an arithmetic processing unit 104, a clock conversion unit 105, a timer 106, and a clock control unit 108 as various functions.

  The first clock generator 102 multiplies or divides the frequency of the reference clock oscillated by the vibrator 101 to generate the first clock PCK having a predetermined frequency. The first clock PCK is a clock for executing the control program that has been read into the RAM 15 and temporarily stored. The first clock PCK is supplied to the clock control unit 108. The first clock PCK is supplied to the second clock generator 103. In the present embodiment, the frequency of the first clock PCK is 200 MHz. The first clock generation unit 102 of this embodiment is an example of the clock generation unit of the present invention.

  The second clock generator 103 further divides the frequency of the first clock PCK to generate the second clock MCK. The second clock generation unit 103 includes a frequency divider that divides the frequency of the supplied first clock PCK. Therefore, the second clock MCK has a lower frequency than the first clock PCK. In the present embodiment, a 100 MHz second clock MCK is generated using a known frequency divider. The second clock generation unit of this embodiment is an example of the clock generation unit of the present invention.

  The clock control unit 108 performs control to supply the first clock PCK to the arithmetic processing unit 104 or stop the supply.

  The arithmetic processing unit 104 executes arithmetic processing according to the control program in synchronization with the supplied first clock PCK. Specifically, when the first clock PCK is supplied to the arithmetic processing unit 104 via the clock control unit 108, the arithmetic processing unit 104 receives each control command of the control program temporarily stored in the RAM 15. The processes are sequentially executed in synchronization with the clock PCK. The arithmetic processing unit 104 of this embodiment is an example of a program control unit of the present invention. A control command executed by the arithmetic processing unit 104 is supplied to the switch switching unit 192 or the clock supply block 107. When the control command is executed, the switch switching unit 192 switches the FET switch between on and off.

  The clock converter 105 converts the frequency of the supplied second clock MCK into a plurality of different frequencies. The clock CCK whose frequency is converted by the clock converter 105 is supplied to the clock supply block 107. In the embodiment, the clock supply block 107 includes the electrophoretic display unit 4, the display control unit 18, the memory card I / F 11, the flash memory 13, the EEPROM 14, the RAM 15, and the wireless communication unit 17. Specifically, the clock conversion unit 105 converts the frequency of the second clock MCK to a frequency suitable for the operation of each device constituting the clock supply block 107. By supplying the converted clock CCK to each device, each device is operated based on the clock CCK supplied to each device. Electric power is consumed by operating each device. The clock conversion unit 105 includes a frequency divider that divides the frequency. Specifically, the clock conversion unit 105 includes a plurality of frequency dividers as with the second clock generation unit 103. In the present embodiment, the clock CCK converted to 25 MHz is supplied to the memory card I / F 11, the flash memory 13, and the display control unit 18, respectively. The clock CCK converted to 100 MHz is supplied to the EEPROM 14 and the RAM 15, respectively. The second clock MCK may be generated as the conversion clock CCK without being converted. The clock CCK converted to 4 MHz is supplied to the wireless communication unit 17. The clock conversion unit 105 of this embodiment is an example of the clock generation unit of the present invention.

  The timer 106 performs a time measuring operation by counting the reference clock oscillated by the vibrator 101. A reference clock is supplied from the vibrator 101 to the timer 106. Based on the time counted by the timer 106, a command for controlling on / off of the power switch 2 is supplied. Based on the time counted by the timer 106, a command for generating the first clock PCK is supplied to the first clock generator 102. Based on the time counted by the timer 106, a command to supply the first clock PCK to the arithmetic processing unit 104 or to stop the supply is supplied to the first clock control unit 108.

  The power switch 2 is operated by the user. When the power of the image display device 1 is turned on by the power switch 2, the battery 16 supplies power to the CPU 10. Specifically, the switching circuit supplies and stops power according to whether the power switch 2 is turned on or off. When the power of the image display device 1 is turned off by the power switch 2, the power supply from the battery 16 to the CPU 10 is stopped by the switching circuit.

  The flash memory 13 includes a control program storage area 131. The control program storage area 131 stores a control program. The control program is a program for controlling the image display device 1. Specifically, the control program is firmware of the image display device 1. The firmware is a program for mainly operating hardware in the image display apparatus 1. The operation of the firmware includes an operation check, activation, and the like of hardware devices that constitute the image display device 1. The control program storage area 131 includes a rewrite processing program storage area 132. The rewrite processing program storage area 132 stores a rewrite processing program. The rewrite processing program rewrites the display of the nonvolatile display unit 4 according to the display information. The control program storage area 131 of the embodiment is an example of the program storage unit of the present invention.

  The memory card interface 11 is an interface for connecting to a memory card 12 which is a portable external memory. A memory card other than the SD card (registered trademark) used in the present embodiment may be used. The memory card 12 has a display information storage area 121. The display information storage area 121 stores display information for displaying an image on the electrophoretic display unit 4. The display information is composed of pixel information and coordinate information. The pixel information is information for designating display (black) and non-display (white) for each pixel space 21 of the electrophoretic display unit 4. The coordinate information is information indicating a position where text, an image, a figure, and the like are displayed on the electrophoretic display unit 4 according to the display information stored in the display information storage area 121. The display information is stored in a file format composed of a plurality of pages. Instead of the memory card 12, an external storage device such as an HDD may be used. The memory card interface 11 of this embodiment is an example of the information acquisition unit of the present invention.

  The RAM 15 is a volatile memory that is composed of a known RAM and that can write and read information and control commands at high speed. The RAM 15 includes a control program temporary storage area 151 and a display information temporary storage area 152. The RAM 15 of the embodiment is an example of a temporary storage unit of the present invention. In this embodiment, an SDRAM is used as the RAM 15. The SDRAM is a DRAM that operates in synchronization with a clock. The SDRAM reads or writes information in synchronization with the clock. An SDRAM requires a refresh operation to hold information. The refresh operation of the SDRAM of this embodiment is performed in synchronization with the clock. Note that the refresh operation of the SDRAM may be performed by a self-refresh operation at a predetermined period or a predetermined timing in the internal configuration of the SDRAM without synchronizing with an externally supplied clock.

  The control program temporary storage area 151 temporarily stores the control program stored in the control program storage area 131. The control program temporary storage area 151 temporarily stores control commands and processing results for controlling the image display device 1. The control command temporarily stored in the control program temporary storage area 151 is executed by the CPU 10.

  The display information temporary storage area 152 temporarily stores pixel information and coordinate information stored in the display information storage area 121 as display information. The display information stored in the display information temporary storage area 152 is display information relating to a new image displayed by the electrophoretic display unit 4 when the operation keys 5 and 6 are operated.

  The EEPROM 14 is a non-volatile memory that retains stored contents even when power supply is interrupted. The EEPROM 14 has a display file information storage area 141 and a displayed page information storage area 142. The EEPROM 14 of this embodiment is an example of the position storage unit of the present invention.

  The display file information is information representing a file name of display information related to an image currently displayed by the electrophoretic display unit 4 when the operation keys 5 and 6 are operated.

  The displayed page information is information indicating the page number of the display information currently displayed by the electrophoretic display unit 4 when the operation keys 5 and 6 are operated. The displayed page number information 142 represents the page number of the file currently displayed by the electrophoretic display unit 4.

  The wireless communication unit 17 is a module having a known configuration for transmitting and receiving information to and from Bluetooth.

  The battery 16 is connected to the CPU 10, the power switch 2, and the power control unit 19. When the image display device 1 includes a USB connection terminal, the battery 16 is charged from the power source of the personal computer when the personal computer and the image display device 1 are connected by USB. Alternatively, the battery 16 is charged from the external power source by connecting the external power source such as a commercial power source and the image display device 1 through the outlet.

  The power control unit 19 includes a voltage conversion unit 191 and a switch switching unit 192. The voltage converter 191 converts the voltage supplied from the battery 16 into a voltage having a value suitable for operating various peripheral devices. As shown in FIG. 6, the voltage conversion unit 191 is connected to various peripheral devices connected to the CPU 10. The voltage conversion unit 191 includes an electrophoretic display unit 4, operation keys 5 and operation keys 6, a memory card I / F 11, a flash memory 13, an EEPROM 14, a RAM 15, a wireless communication unit 17, and a display control unit 18. And connected respectively.

  The switch switching unit 192 switches connection between at least a part of various peripheral devices and the voltage conversion unit 191. When the switch switching unit 192 switches the connection, supply and stop of voltage to various peripheral devices are controlled. FIG. 6 is a block diagram illustrating a connection configuration of the power control unit 19 and peripheral devices. As illustrated in FIG. 6, the switch switching unit 192 includes FET switches 26 to 28. Each FET switch is a known switching element that includes a field effect transistor and changes to an on or off state by applying or stopping a voltage to the gate terminal. The CPU 10 generates a switching command for turning on or off the FET switches 26 to 28. According to the switching command, the FET switches 26 to 28 are turned on or off, and connect or disconnect the various peripheral devices connected to each FET switch and the voltage conversion unit 191. When the FET switches 26 to 28 are turned on, a voltage is applied to various devices connected to the FET switch. In the present embodiment, the RAM 15, the flash memory 13, the EEPROM 14, the operation keys 5 and the operation keys 6 are directly connected to the voltage conversion unit 191. The operation keys 5 and 6, the RAM 15, the flash memory 13, and the EEPROM 14 are not connected to the FET switch as described above. As shown in FIG. 4, the CPU 10 and the power control unit 19 are supplied with power from the battery 16 independently of the supply and stop of the voltage by the power control unit 19. Therefore, even when the voltage conversion unit 191 and various peripheral devices are not connected by the switch switching unit 192, power is supplied to the CPU 10 and the power control unit 19. Even when the voltage conversion unit 191 and various peripheral devices are not connected by the switch switching unit 192, the CPU 10 can accept the operation of the operation keys 5 and 6. When the operation signal is not supplied from the operation keys 5 and 6 for a predetermined time, the CPU 10 sends a command for shutting off the voltage conversion unit 191 and various peripheral devices to the switch switching unit 192. Further, when an operation signal is supplied from the operation keys 5 and 6, the CPU 10 sends a command to connect the voltage conversion unit 191 and various peripheral devices to the switch switching unit 192. The power control unit 19 of the embodiment is an example of the power control unit of the present invention.

  The display control unit 18 includes a drive voltage generation unit 181 and a voltage application control unit 182. The driving voltage generator 181 generates a driving voltage to be applied to the lower electrode 52 and the upper electrode 62. The drive voltage generator 181 boosts the voltage supplied from the battery 16. Then, the drive voltage generation unit 181 generates the boosted voltage as a voltage to be applied to each electrode of the electrophoretic display unit 4. The drive voltage generator 181 of the embodiment is an example of the drive voltage generator of the present invention. The voltage application control unit 182 performs control to apply a predetermined drive voltage to the lower electrode 52 and the upper electrode 62. Specifically, the voltage application control unit 182 determines the upper electrode 62 and the lower electrode 52 to which a predetermined voltage is applied in accordance with pixel information constituting display information. For the determined electrode, the voltage application control unit 182 determines whether to apply the drive voltage generated by the display voltage generation unit 181 and determines the polarity of the voltage to be applied. In the present embodiment, a common drive voltage (for example, 0 volt) is applied to the upper electrode 62. A positive polarity voltage is applied to the lower electrode 52 so that an electric field having a magnitude that can be rewritten to “display (black)” is generated between the upper electrode 62 and the lower electrode 52. A negative polarity voltage is applied to the lower electrode 52 so that an electric field of a magnitude that can be rewritten to “non-display (white)” is generated between the lower electrode 52 and the upper electrode 62. By applying a negative polarity voltage lower than that of the upper electrode 62 to the lower electrode 52, the negatively charged white charged particles 33a are attracted upward toward the display layer 63 shown in FIG. On the other hand, by applying a positive polarity voltage higher than that of the upper electrode 62 to the lower electrode 52, the positively charged black charged particles 33b are attracted upward toward the display layer 63 shown in FIG. The black charged particles 33b are attracted to the display layer 63, whereby an image can be displayed. Even when the supply of voltage to the upper electrode 62 and the lower electrode 52 of the electrophoretic display unit 4 is stopped, the attracted state of the charged particles 33a and the charged particles 33b is maintained by the viscosity and image power of the dispersion medium 34. When an electric field in the reverse direction is generated in which the charged particles 33a and the charged particles 33b can move in the dispersion medium 34, the charged particles 33a and the charged particles 33b move again, and the position is reversed, so that the image is rewritten. The voltage application control unit 182 of this embodiment is an example of the voltage control unit of the present invention. In the present embodiment, the display control unit 18 newly generates a clock based on the converted clock CCK. In synchronization with the newly generated clock, the voltage application control unit 182 supplies a command for applying a predetermined voltage to each electrode to the electrophoretic display unit 4. The display control unit 18 of the present embodiment is an example of the display control unit of the present invention.

<Operation of Embodiment>
The operation and action of the image display apparatus 1 of the present embodiment having the above-described configuration will be described with reference to the accompanying drawings. FIG. 7 is a flowchart showing a processing procedure of the main operation in the image display apparatus 1. The main operation is executed by various circuit configurations of the CPU 10. Specifically, the arithmetic processing unit 104 generates various commands for the main operation. When the battery 16 and the CPU 10 are connected by the power switch 2, power is supplied to the CPU 10. When the battery 16 and the CPU 10 are connected, the main operation is executed. The control program is executed when the first clock PCK is supplied to the arithmetic processing unit 104, while the main operation is executed when the battery 16 and the CPU 10 are connected. In the main operation, the control program mainly performs power control and page rewriting control. The power control includes control of the switch switching unit 192 and control of supply or stop of supply of the first clock PCK and the second clock MCK. Mainly, the page rewriting control is drive voltage generation control and drive voltage application control.

(Main operation)
First, in step S101, it is determined whether the power switch 2 of the apparatus is turned on by the user. Step S101 is repeated until it is determined that the power switch is turned on.

  In step S <b> 102, the CPU 10 sends a command to generate an operating voltage for each peripheral device to the power control unit 19 based on the voltage supplied from the battery 16. Based on a command from the CPU 10, the voltage conversion unit 191 converts the voltage from the battery 16 into a voltage value suitable for various peripheral devices. The converted voltage is supplied to various peripheral devices. When the FET switches 26 to 28 are not turned on, no voltage is supplied to the electrophoretic display unit 4, the memory card I / F 11, the wireless communication unit 17, and the display control unit 18. Even when the FET switches 26 to 28 are not turned on, power is supplied to the RAM 15, the flash memory 13, the EEPROM 14, the operation keys 5, and the operation keys 6. In step S102, the FET switches 26 to 28 are turned off.

  In step S <b> 103, the CPU 10 sends to the flash memory 13 and the RAM 15 a command to expand the control program stored in the flash memory 13 in the control program temporary storage area 151 and temporarily store it. By storing the control program in the control program temporary storage area 151 of the RAM 15, the arithmetic processing unit 104 can execute the control program.

  In step S104, the CPU 10 generates the first clock PCK. At this time, the first clock control unit 108 supplies the generated first clock PCK to the arithmetic processing unit 104. Further, the CPU 10 generates a second clock MCK. The generated second clock MCK is converted by the clock converter 105 to generate a converted clock CCK. The converted clock CCK is supplied to the clock supply block 107. Specifically, the clock conversion unit 105 converts the frequency of the second clock MCK into a plurality of types of frequencies suitable for each peripheral device. A plurality of types of clocks CCK whose frequencies have been converted are supplied to the memory card I / F 11, the flash memory 13, the EEPROM 14, the RAM 15, the wireless communication unit 17, the display control unit 18, and the electrophoretic display unit 4, respectively. By supplying the converted clock CCK to each peripheral device, each peripheral device is operated in synchronization with the clock CCK. The display control unit 18 receives display information to be displayed by the electrophoretic display unit 4 in synchronization with the clock CCK. In addition, the display control unit 18 transmits an application command for applying a predetermined voltage to the upper electrode 62 and the lower electrode 52 of the electrophoretic display unit 4 based on the display information in synchronization with the clock CCK. The electrophoretic display unit 4 receives the application command sent by the display control unit 18 in synchronization with the clock CCK. The wireless communication unit 17 transmits / receives information to / from Bluetooth in synchronization with the clock CCK. The memory card I / F 11 reads information from the memory card 12 or writes information in synchronization with the clock CCK. The EEPROM 14 reads or writes information in synchronization with the clock CCK. The flash memory 13 reads information in synchronization with the clock CCK. The RAM 15 reads or writes information in synchronization with the clock CCK and performs a refresh operation in synchronization with the clock CCK. The computer of the embodiment and step S104 are an example of the mode switching unit of the present invention. Moreover, step S104 of the embodiment is an example of the mode switching step of the present invention.

  In step S105, the CPU 10 generates a command for executing the control program stored in step S103. That is, by supplying the first clock PCK to the arithmetic processing unit 104 in step S104, each control command of the control program is read from the control program temporary storage area 151 of the RAM 15 in synchronization with the first clock PCK. The arithmetic processing unit 104 sequentially executes the processing. The computer of this embodiment and step S105 are an example of the program control unit of the present invention. Step S105 of the embodiment is an example of a program control step of the present invention. Thereafter, step S106 to step S110 are operated by the CPU 10 executing the control program.

  In step S106, the FET switch is ON / OFF controlled based on the control program executed in step S105. The CPU 10 sends a switching command to the FET switches 26 to 28 constituting the switch switching unit 192. According to the switching command, the FET switches 26 to 28 connect various peripheral devices connected to the FET switch and the voltage conversion unit 191. When the FET switches 26 to 28 are turned on, a voltage is applied to the electrophoretic display unit 4, the memory card I / F 11, the wireless communication unit 17, and the display control unit 18. In step S106, the first mode of the present invention is set.

  In step S107, based on the control program executed in step S105, the CPU 10 sends a command for generating a drive voltage to the drive voltage generator 181.

  In step S108, the page rewriting process is executed based on the control program executed in step S105. Step S108 is executed according to the control program stored in step S103. A predetermined image is displayed on the electrophoretic display unit 4 in accordance with display information temporarily stored in the RAM 15 or display information stored in the memory card 12. That is, whether the drive voltage is applied, the polarity of the drive voltage, and the electrode to be applied are determined according to the display information. In accordance with this determination, the drive voltage generated in step S107 is applied to the upper electrode 62 and the lower electrode 52. Step S108 of the present embodiment is an example of a voltage control step of the present invention.

  In step S109, based on the control program executed in step S105, the CPU 10 starts counting time by the timer 106.

  In step S110, based on the control program executed in step S105, the CPU 10 stops supplying the first clock PCK and supplies the second clock MCK. Specifically, the clock control unit 108 stops supplying the first clock PCK to the arithmetic processing unit 104. Accordingly, the first clock generator 102 generates the first clock PCK, but the first clock controller 108 stops the supply of the first clock PCK to the arithmetic processor 104. The first clock PCK is supplied to the second clock generator 103. The computer of the embodiment and step S110 are an example of the mode switching unit of the present invention. Step S110 of the embodiment is an example of the mode switching step of the present invention. In step S110, the supply of the first clock is stopped, and power is supplied to all peripheral devices including the RAM 15. A mode in which the first clock is stopped and power is supplied to all peripheral devices including the RAM 15 and the electrophoretic display unit 4 is the second mode of the present invention.

  In step S111, it is determined whether or not the operation key 5 or the operation key 6 has been operated by the CPU 10. If it is determined that the operation key 5 or the operation key 6 has been operated, step S104 is executed. If it is not determined that the operation key 5 or the operation key 6 has been operated, step S112 is executed. Step S112 of the embodiment is an example of an operation step and an operation detection step of the present invention.

  In step S112, the CPU 10 determines whether the time counted by the timer 106 is 15 seconds or less. If it is determined that the time is 15 seconds or less, step S113 is executed. If it is not determined that the time is 15 seconds or less, step S111 is executed.

  In step S113, the FET switch is turned off. That is, the FET switches 26 to 28 configuring the switch switching unit 192 disconnect from various peripheral devices. Specifically, in step S <b> 113, a command to supply the first clock PCK to the arithmetic processing unit 104 is supplied to the clock control unit 108 based on the timer 106 counting for 15 seconds. When the first clock PCK is supplied to the arithmetic processing unit 104, the control program sends a switching command to the FET switches 26 to 28 constituting the switch switching unit 192. In accordance with the switching command, the FET switches 26 to 28 cut off the connection between the voltage conversion unit 191 and various peripheral devices. Then, the CPU 10 sends a command to the voltage conversion unit 191 to stop voltage conversion. Step S113 of the embodiment is an example of a power control step of the present invention.

  In step S114, the CPU 10 sends a command for stopping the generation of the first clock PCK to the first clock generation unit 102 based on the control program temporarily activated in step S113. Specifically, the first clock generator 102 stops generating the first clock PCK. Therefore, the clock converter 105 does not supply the converted clock CCK to the clock supply block 107. The computer of the embodiment and step S114 are an example of the mode switching unit of the present invention. Step S114 of the embodiment is an example of the mode switching step of the present invention. In step S114, the supply of the first clock PCK is stopped, and power is supplied to the RAM 15, the flash memory 13, the EEPROM 14, and the operation keys 5 and 6. A mode in which the first clock PCK is stopped and power is supplied to the RAM 15 is the second mode of the present invention.

  In step S115, it is determined whether or not the operation key 5 or the operation key 6 has been operated. If it is determined that the operation key 5 or the operation key 6 has been operated, step S104 is executed. If it is not determined that the operation key 5 or the operation key 6 has been operated, step S116 is executed. Step S115 of the present embodiment is an example of an operation step and an operation detection step of the present invention.

  In step S116, the CPU 10 determines whether the time counted by the timer 106 is 10 minutes or less. If it is determined that the time is 10 minutes or less, step S117 is executed. If it is not determined that the time is 10 minutes or less, step S115 is executed.

  In step S117, the CPU 10 generates an end command to end the timer 106 count.

  In step S <b> 118, the CPU 10 sends to the battery 16 that generates a disconnection command for disconnecting the connection between the battery 16 and the image display device 1. Based on the disconnection command, the connection between the battery 16 and the image display device 1 is disconnected. Therefore, since the RAM 15 is not supplied with power, no information is stored. In step S118, the third mode of the present invention is set. Step S118 of the embodiment is an example of a mode switching unit of the present invention, and is an example of a mode switching step. The supply of the first clock PCK is stopped, and the supply of power to all the peripheral devices including the RAM 15 is stopped. The mode in which the first clock PCK is stopped and the supply of power to all peripheral devices is stopped is the third mode of the present invention.

(Page rewrite processing operation)
In step S <b> 201, it is determined whether display information is stored in the display information temporary storage area 152. If stored, step S204 is executed. If not stored, step S202 is executed.

  In step S202, it is determined whether the display information file is stored in the display file information storage area 141. If stored, step S203 is executed. If not stored, step S206 is executed. When the display file is not stored in the display file information storage area 141, “Null” is stored.

  In step S <b> 203, display information is stored in display information temporary storage area 152. The display information stored in step S203 is display information stored at a predetermined position in the display information storage area 121. The predetermined position is determined based on the display file information stored in the EEPROM 14 and the displayed page information. FIG. 9 is a conceptual diagram showing a storage state in which display information is stored in the display information storage area 121. The display information is stored in the display information storage area 121 as a file. The file may be composed of a plurality of pages. The display information storage area 121 stores files according to the hierarchical structure of folders. A folder 91-a illustrated in FIG. 9 includes three folders 91-b, 91-c, and 91-d at lower hierarchical positions. The folder 91-b includes two files 92-a and 92-b at lower hierarchical positions. FIG. 10 shows an example of a storage state in which the display file information and the displayed page information are stored in the EEPROM 14. As shown in FIG. 10, the display file information is “experiment / experiment overview / experimental instrument”. The displayed page information is “3”. "Experiment \ Experiment Outline \ Experimental Instrument" indicates a file 92-a located in a lower hierarchy of the folder 91-a and the folder 91-b. “3” in the displayed page information indicates “third page”. Therefore, the display information currently displayed by the electrophoretic display unit 4 is determined to be “page 3” of the display file information “experimental instrument”. The file indicated by the determined display file information is read from the display information storage area 121 and temporarily stored in the display information temporary storage area 152. Display information related to at least the pages before and after the page indicated by the displayed page information among the plurality of pages constituting the above-described file may be temporarily stored in the display information temporary storage area 152.

  In step S <b> 204, an image is displayed on the electrophoretic display unit 4 according to the display information stored in the display information temporary storage area 152. Specifically, the voltage application control unit 182 performs control to apply the drive voltage generated by the drive voltage generation unit 181 in accordance with the pixel information constituting the display information. The drive application control unit 182 determines the upper electrode 62 and the lower electrode 52 to which a predetermined voltage is applied in accordance with the pixel information constituting the display information. For the determined electrode, the voltage application control unit 182 determines whether to apply the drive voltage generated by the drive voltage generation unit 181 and determines the polarity of the voltage to be applied. The determined voltage is applied to the upper electrode 62 and the lower electrode 52. For example, when the operation key 5 is operated in a state where the “third page” of the display file information “experimental instrument” is displayed, the “second page” of the display file information “experimental instrument” is displayed. When the operation key 6 is operated, “page 4” of the display file information “experimental instrument” is displayed.

  In step S205, the display file information and the displayed page information are stored in the display file information storage area 141 and the displayed page information storage area 142, respectively. The display file information and the displayed page information are file information and page information regarding the file name and the number of pages of the display information representing the image displayed in step S204. For example, when the operation key 5 is operated in step S <b> 204, file information “experiment / experiment overview / experimental instrument” is stored in the display file information storage area 141. Further, the page information “2” is stored in the displayed page information storage area 142.

  In step S <b> 206, display information displayed in response to an instruction from operation key 5 or operation key 6 is temporarily stored in display information temporary storage area 152. Display information displayed as an image on the electrophoretic display unit 4 is temporarily stored in the display information temporary storage area 152.

(Modification 1)
Modification 1 of this embodiment will be described. In this embodiment, a portable image display device is described. Modification 1 may be other than a portable image display device. For example, an image display device that can be installed at a predetermined location may be used. In that case, electric power may be supplied from an external power source such as a commercial power source via an outlet instead of the battery provided in the display device.

(Modification 2)
A second modification of the present embodiment will be described. In the present embodiment, the RAM 15 is used as a temporary storage unit. In the second modification, a temporary storage unit other than the RAM may be used. A volatile memory that can write or read information and control commands at high speed may be used.

(Modification 3)
A third modification of the present embodiment will be described. In the present embodiment, a NAND flash memory 13 is used as a program storage unit. In the third modification, a storage unit other than the flash memory may be used. A non-volatile memory that can store the control program may be used.

(Modification 4)
Modification 4 of the present embodiment will be described. In the present embodiment, the electrophoretic display unit 4 is used as the nonvolatile display unit. In the fourth modification, the display device is not particularly limited as long as the display device has a memory effect that maintains the displayed display information when the drive voltage is not supplied. A display device composed of electronic powder particles may also be used. A cholesteric liquid crystal may also be used.

(Modification 5)
Modification 5 of this embodiment will be described. In the present embodiment, the voltage conversion unit 191 is directly connected to the flash memory 13, the EEPROM 14, the RAM 15, and the operation keys 5 and 6. In Modification 5, at least the voltage conversion unit may be directly connected to the RAM, and the voltage conversion unit may be connected to at least one of the flash memory, the EEPROM, and the operation keys 5 and 6 via the FET switch. In the modified example 5, when the voltage conversion unit is connected to the flash memory 13, the EEPROM 14, the operation key 5, and the operation key 6 through the FET switch, the FET switch is the same as the FET switches 26 to 28 of the present embodiment. On / off control is performed by operation processing.

(Modification 6)
A sixth modification of the present embodiment will be described. In the present embodiment, in the second mode, the operating voltage is supplied from the voltage conversion unit 191 to the RAM 15, the flash memory 13, the EEPROM 14, the operation keys 5, and the operation keys 6. In Modification 6, at least the voltage conversion unit 191 and the RAM may be connected, and the operating voltage may be supplied to the RAM.

(Modification 7)
Modification 7 of the present embodiment will be described. In the present embodiment, the execution or stop of the control program is controlled by the first clock PCK. In the modified example 7, in addition to the control by the first clock PCK, the execution or stop of the control program may be controlled by supplying or stopping power to the RAM.

(Modification 8)
Modification 8 of the present embodiment will be described. In the present embodiment, display information is acquired from the memory card 12. In Modification 8, display information may be obtained from an HDD built in the image display device.

(Modification 9)
Modification 9 of the present embodiment will be described. In the present embodiment, an SDRAM is used as the RAM 15. In the modification 9, a DRAM (Dynamic Random Access Memory) that is not synchronized with a clock other than the SDRAM may be used. An SRAM may be used instead of the DRAM. When the SRAM is used, a refresh operation for holding information in the SRAM (Static Random Access Memory) becomes unnecessary. When an SRAM is used, information reading or writing operation may be performed without synchronizing with the clock.

(Modification 10)
A modification 10 of the present embodiment will be described. As shown in FIG. 5, in the present embodiment, the second clock generation unit 103 generates the second clock MCK by dividing the first clock PCK. Then, the clock conversion unit 105 converts the second clock MCK into a clock CCK that is a frequency suitable for the operation of each device. In the modified example 10, a frequency suitable for each device may be generated by the clock generator without using the frequency divider. Specifically, the first clock generation unit of this embodiment is provided to generate the frequency of each device.

(Modification 11)
A modification 11 of the present embodiment will be described. In the present embodiment, in this embodiment, the frequency of the first clock PCK is 200 MHz. The frequency of the second clock MCK is 100 MHz. The frequency of the clock CCK supplied to the memory card I / F 11, the flash memory 13, the EEPROM 14, and the display control unit 18 is 25 MHz. The clock CCK supplied to the wireless communication unit 17 is 4MH. In the modification 11, the frequency of the first clock PCK may be lower than that of the second clock MCK. Further, the frequency of the first clock PCK may be lower than the frequency of the clock CCK. In this case, the second clock MCK may be generated by dividing the frequency of the reference clock, and the first clock PCK may be generated by dividing the second clock MCK. Further, the second clock MCK may be generated by multiplying the first clock PCK.

(Modification 12)
A modification 12 of the present embodiment will be described. Following step S108, which is the page rewriting process of the main operation of the present embodiment, step S109 is executed. Execution of step S109 causes the first clock control unit 108 to stop supplying the first clock PCK to the arithmetic processing unit 104. In Modification 12, after the rewriting process is completed by the electrophoretic display unit in step S108, the electrophoretic display unit may issue a rewrite completion command. In this case, step S109 is executed based on the generation of the rewrite completion command.

(Modification 13)
Modification 13 of the present embodiment will be described. In step S116 of the main operation of the present embodiment, it is determined whether or not the count time is 10 minutes or less. When the count time is 10 minutes or less, the connection between the battery 16 and the image display device 1 is disconnected based on the disconnection command. In the modified example 13, instead of determining whether the count time is 10 minutes or less in step S116, it may be determined whether the power of the image display device 1 is turned off by the power button 2. When the power of the image display device 1 is turned off by the power switch 2, the power supply from the battery 16 to the CPU 10 is stopped by the switching circuit.

(Modification 14)
A modification 14 of the present embodiment will be described. In the present embodiment, as the second mode, the first clock is stopped, and power is supplied to all peripheral devices including the drive voltage generation unit 181 and the voltage application control unit 182 that constitute the display control unit 18. In the modified example 14, in the second mode, the first clock may be stopped, and power may be supplied to at least the drive voltage generation unit and the voltage application control unit.

(Modification 15)
A modification 15 of the present embodiment will be described. In the present embodiment, the drive voltage is generated by the drive voltage generator 181 as the second mode of the present invention. In the modified example 15, as the second mode, the drive voltage generation unit may generate a preparation voltage for generating a voltage for rewriting the display of the electrophoretic display unit 4.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 Power switch 4 Electrophoresis display part 5, 6 Operation key 10 CPU
11 Memory Card Interface 12 Memory Card 13 Flash Memory 14 EEPROM
15 RAM
DESCRIPTION OF SYMBOLS 16 Battery 17 Wireless communication part 18 Display control part 19 Power control part 21 Pixel space 26-28 FET switch 33a, 33b Charged particle 34 Dispersion medium 35 Pixel space 40 Mask part 50 Lower board | substrate 51 Lower electrode protective film 52 Lower electrode 53 Case Support part 60 Upper substrate 61 Upper electrode protective film 62 Upper electrode 63 Display layer 70 Display part 71 Bulkhead 91-a Folder 91-b Folder 91-c Folder 91-d Folder 92-a File 92-b File 92-c File 92 -D file 101 vibrator 102 first clock generation unit 103 second clock generation unit 104 arithmetic processing unit 105 clock conversion unit 106 timer 107 clock supply unit 108 clock control unit 121 display information storage area 131 control program information storage area 132 Processing program information storage area 141 displays file information 142 displayed in the page information 151 control program information temporary storage area 152 displays information temporary storing area 181 a driving voltage generator 182 voltage application control unit 191 voltage converting unit 192 switches the switching section

Claims (7)

A display device having a nonvolatile display unit that rewrites a display when a drive voltage is supplied according to display information and maintains a display when the supply of the drive voltage is stopped,
An operation unit operable to instruct various operations of the display device;
A non-volatile program storage unit for storing a control program for controlling the display device;
A program control unit that executes a control program stored in the program storage unit or performs control to stop the execution;
A drive voltage generator for generating the drive voltage;
A voltage control unit that supplies the driving voltage to the non-volatile display unit or executes a first control to stop the supply;
When the operation unit is operated to rewrite the display of the non-volatile display unit, the voltage control unit supplies the drive voltage to the non-volatile display unit by the first control, and the program control unit From the second mode in which the execution of the control program is stopped, the voltage control unit supplies the drive voltage to the nonvolatile display unit by the first control, and the program control unit executes the control program. A mode switching unit that switches from the first mode to the second mode when the display is rewritten according to the display information in the first mode;
A display device comprising: A volatile temporary storage unit that temporarily stores the control program stored in the program storage unit;
A first clock for the program control unit to execute a control program temporarily stored in the temporary storage unit; and a second clock for the voltage control unit to supply the drive voltage by the first control. A generated clock generator; and
A power control unit that executes at least a second control for supplying power to the temporary storage unit or stopping the supply;
With
The program control unit executes the control program based on the first clock,
The voltage control unit supplies a command to supply the driving voltage based on the second clock to the nonvolatile display unit,
When the mode switching unit switches from the second mode to the first mode, the power control unit supplies power to at least the temporary storage unit, and the clock generation unit includes the first clock and the first mode. And when the mode switching unit switches from the first mode to the second mode, the power control unit supplies power to at least the temporary storage unit, and the clock generation The display device according to claim 1, wherein the unit stops the first clock and generates the second clock.   The display device according to claim 2, wherein the clock generation unit generates the first clock having a higher frequency than the second clock. An information acquisition unit that acquires the display information from a nonvolatile information storage unit that stores the display information that causes the nonvolatile display unit to perform a predetermined display;
A volatile temporary storage unit that temporarily stores the control program stored in the program storage unit and the display information acquired by the information acquisition unit;
When the operation unit is operated, a display control unit that causes the nonvolatile display unit to perform a predetermined display according to display information stored in the temporary storage unit;
A non-volatile position storage unit that stores a storage position where display information relating to an image currently displayed on the non-volatile display unit is stored in the information storage unit;
With
The power control unit supplies at least power to the temporary storage unit or stops the supply of the second control, the nonvolatile display unit, the information acquisition unit, the program storage unit, and the temporary storage unit. Supplying power to the display control unit and the position storage unit, or executing third control to stop the supply of power;
The mode switching unit is configured such that the voltage control unit supplies the driving voltage to the nonvolatile display unit by the first control and supplies power by the second control, and the program control unit executes a control program. The first mode to be executed, the voltage control unit supplies the driving voltage to the nonvolatile display unit by the first control, supplies power by the second control, and the program control unit The second mode in which the execution of the control program is stopped, and the power control unit stops the supply of the driving voltage to the nonvolatile display unit by the first control, and the power supply is stopped by the third control. And the program control unit can switch between the third mode in which the execution of the control program is stopped,
The display control unit according to the display information acquired from the storage position by the information acquisition unit and stored in the temporary storage unit when the mode switching unit switches from the third mode to the first mode. The non-volatile display unit according to the display information stored in the temporary storage unit when a predetermined display is displayed on the non-volatile display unit and the mode switching unit switches from the second mode to the first mode. The display device according to claim 1, wherein a predetermined display is displayed.   The display device according to claim 4, wherein the mode switching unit switches to the third mode after a predetermined first time has elapsed since switching to the second mode. An operation step for instructing various operations of the display device having a nonvolatile display unit that rewrites the display when the drive voltage is supplied according to the display information and maintains the display when the supply of the drive voltage is stopped;
A voltage control step of performing a first control for causing the drive voltage generating unit for generating the drive voltage to supply the drive voltage to the nonvolatile display unit or stopping the supply;
Non-volatile for controlling the display device with the driving voltage supplied to the non-volatile display unit by the voltage control step when an instruction is given by the operation step to rewrite the display of the non-volatile display unit From the second mode in which execution of the control program stored in the program storage unit is stopped to the first mode in which the control program is executed in a state where the drive voltage is supplied to the nonvolatile display unit by the voltage control step. A mode switching step of switching from the first mode to the second mode when the display is rewritten according to the display information in the first mode;
According to the mode switched by the mode switching step, the control program is executed, or the program control step of stopping the execution,
A display method comprising: Detects whether or not an operation has been performed to instruct various operations of a display device having a nonvolatile display unit that rewrites the display when the drive voltage is supplied according to the display information and maintains the display when the supply of the drive voltage is stopped An operation detection step to perform,
A voltage control step for instructing a first control to cause the drive voltage generation unit for generating the drive voltage to supply the drive voltage to the nonvolatile display unit or to stop the supply;
When an operation for rewriting the display of the nonvolatile display unit is detected by the operation detection step, the display device is controlled in a state where the supply of the drive voltage to the nonvolatile display unit is commanded by the voltage control step. The control program in a state in which the supply of the drive voltage to the nonvolatile display unit is instructed by the voltage control step from the second mode in which execution of the control program stored in the nonvolatile program storage unit is stopped A mode switching step of switching from the first mode to the second mode when the display is rewritten according to the display information in the first mode.
A display program for causing a computer to execute the control program according to the mode switched by the mode switching step or to stop the execution of the control program.