JP2018061320A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a personal digital assistant comprising a novel power source and a power supply control method, which is surely available (capable of making contact such as call transmission and reception or mail transmission and reception) in the case of emergency although there is the risk that an important function such as an emergency telephone relating to survival may not be utilized as needed when a battery is wasted and its power becomes zero while the personal digital assistant is used.SOLUTION: Two or more secondary batteries are provided in one electronic apparatus and separated into a normal-time battery and an emergency (temporary) secondary battery. When using the temporary secondary battery, available functions are restricted, such that desired remaining power is secured. When using the temporary secondary battery, a power saving mode (also called emergency mode) is set and in order to execute only an important function (communication action) such as an emergency telephone relating to survival as required, other functions are stopped and restricted.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to an electronic device and a method for operating the electronic device.

  Note that one embodiment of the present invention is not limited to the above technical field. Technical fields of one embodiment of the present invention include electronic devices, display devices, display modules, semiconductor devices, light-emitting devices, power storage devices, storage batteries, storage devices, lighting devices, input devices (eg, touch sensors), input / output devices (For example, a touch panel etc.), those driving methods, or those manufacturing methods can be mentioned as an example.

  Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, or the like is one embodiment of a semiconductor device. In addition, an imaging device, an electro-optical device, a power generation device (including a thin film solar cell, an organic thin film solar cell, and the like) and an electronic device may include a semiconductor device.

As a kind of electronic equipment, various portable information terminals (cell phones, smartphones, and the like) are widely used, and most devices include a display unit for displaying and a secondary battery that can be repeatedly charged.

Since the display of a portable information terminal is difficult to see when used under external light, the brightness of the backlight is increased for a liquid crystal display device, and the luminance of an EL element is increased for an EL display device. It is increasing. However, increasing the luminance of the backlight and the luminance of the EL element leads to an increase in power consumption, which may be one of the causes for accelerating a decrease in the remaining battery level of the portable information terminal.

In a conventional portable information terminal equipped with one battery pack as a power supply form, the user manages the remaining battery level and charges it appropriately. However, there may be an inconvenience that the remaining battery power is exhausted depending on the convenience of the user and the usage environment.

Manufacturers supplying portable information terminals are required to increase the capacity of the battery pack, but increasing the capacity increases the weight of the battery pack or increases the time required for charging. There is a fear. In addition, high safety, large capacity and thin secondary batteries are difficult to manufacture and are expensive. Therefore, it is a burden for the user to purchase a spare battery and always carry it. For safety reasons, there are models in which the user cannot freely replace the secondary battery depending on the portable information terminal.

In a smartphone, if the Internet connection setting (wireless setting) is turned on to enable a smooth connection at all times, a radio wave is always transmitted to continuously search for an optimum connection point. As a result, the battery capacity decreases even during a period when the user is not effectively using the Internet.

In addition, if an application that automatically updates a smartphone is downloaded, power is consumed without the user's knowledge and the remaining battery level is reduced.

In addition, when an application or the like that constantly checks position information such as GPS is downloaded to the smartphone, information is periodically received or transmitted, so that power is consumed and the remaining battery level is reduced.

In addition, if a user misoperates and leaves an application such as a game running, the battery may become zero without even being noticed by the user, and even the information terminal may not be able to be turned on. .

As described above, in an information terminal such as a smartphone, in particular, the user must always know the remaining battery level, which is a burden. Furthermore, secondary batteries that are widely used as battery packs for information terminals are lithium ion secondary batteries, which have various advantages, but also have drawbacks.

FIG. 2 shows an example of a discharge diagram of a lithium ion secondary battery. The vertical axis represents voltage, and the horizontal axis represents elapsed time when the discharge conditions are constant. As shown in FIG. 2, the lithium ion secondary battery has an advantage that it can supply an almost constant voltage when the remaining amount is between 80% and 90% after one full charge. The voltage change occurs between the last 10% and 20%, which approaches zero remaining. Therefore, when a specific threshold value is provided and a warning is issued when the voltage falls below the threshold value, there is a warning about the remaining battery level when the voltage corresponding to the remaining amount that causes a sudden voltage change is used as the threshold value. Sometimes it can be said that the timing for recharging is too late. In addition, if the voltage relative to the remaining amount that has a margin for the remaining amount that causes a sudden voltage change is used as a threshold, there is a possibility that a warning will be issued even if there is still a margin in the remaining amount of the battery, or an instantaneous voltage due to noise There is also the possibility of false warnings for fluctuations.

In addition, in order to avoid running out of charge at the information end, increasing the number of times of charging and periodically repeating full charging will accelerate the deterioration of the lithium ion secondary battery. It has the disadvantage of being premature.

  Patent Document 1 shows an example of an electronic device on which a plurality of secondary batteries are mounted.

JP-A-2015-164392

If the battery is wasted when the portable information terminal is used and the remaining battery level becomes zero, an important function related to the existence of life such as an emergency call may not be available when necessary.

It is an object of the present invention to provide a portable information terminal including a novel power source and a power source control method that can be used reliably (communication such as call transmission and reception, mail transmission and reception) in an emergency.

It is another object of the present invention to reduce the power consumption of the display device and prevent the remaining battery level from decreasing by switching to an optimal display mode according to the usage environment.

One electronic device is provided with two or more secondary batteries, and is divided into a normal battery and an emergency (temporary) secondary battery. When a temporary secondary battery is used, a desired remaining amount is secured by limiting usable functions. When using a secondary battery for temporary use, set it to a power saving mode (also called emergency mode), for example, to execute only important functions (communication actions) related to the existence of life, such as emergency calls, when necessary , Stop and limit other functions.

A portable information terminal, which is an example of an electronic device, needs to periodically transmit position information to a base station, but this frequency is reduced when a temporary secondary battery is used. When a call signal is received from a base station or when an emergency call is made from a portable information terminal, a call can be made.

When the remaining amount of the emergency battery is the first power, the remaining amount of the emergency battery is changed from the first power to the threshold power in the emergency mode (the emergency battery required for a call). The first power may be set so that the time until the remaining power is reduced to a desired time. The standard of the time is preferably 100 hours or more and 200 hours or less with 72 hours as a standard for saving lives after a disaster occurs. It is also desirable to include power for making calls as many times as necessary. For example, it is desirable that a call can be made 10 times or more and 20 times or less.

The charging method may start charging a plurality of secondary batteries at the same time, but the charging may be performed with priority over the first emergency secondary battery.

In addition, since it is preferable that the power consumption in the display portion is small in the emergency mode, the display portion preferably includes a reflective display element.

  The reflective liquid crystal element is displayed using external light as a light source. A display device using a reflective liquid crystal element can obtain a clear and beautiful image. In addition, since no backlight is required, power consumption can be reduced. In addition, response speed is faster than electronic paper. Here, in the display device using the reflective liquid crystal element, by using an idling stop (IDS) drive described later, the power consumption of the display device can be extremely reduced. A display device combining a reflective liquid crystal element and IDS driving is a portable terminal that displays books, particularly books including figures and images, such as textbooks and reference books, because of its low power consumption and beautiful display image quality. Are better.

Further, since the display on the display unit in the normal mode is preferably a vivid display, the display unit is preferably configured to be capable of hybrid display.

  Hybrid display is a method of displaying characters or images on one panel by using reflected light and self-light emission in combination with each other to complement color tone or light intensity. Alternatively, the hybrid display is a method for displaying characters and / or images using light from a plurality of display elements in the same pixel or the same sub-pixel. However, when a hybrid display that performs hybrid display is viewed locally, a pixel or sub-pixel displayed using any one of the plurality of display elements and a pixel displayed using both the plurality of display elements Alternatively, it may have sub-pixels.

  Note that in this specification and the like, a display that satisfies any one or a plurality of expressions of the above configuration is referred to as a hybrid display.

  The hybrid display has a plurality of display elements in the same pixel or the same sub-pixel. Examples of the plurality of display elements include a reflective element that reflects light and a self-luminous element that emits light. Note that the reflective element and the self-luminous element can be controlled independently. The hybrid display has a function of displaying characters and / or images in the display unit using either or both of reflected light and self-light emission.

One of the configurations of the invention disclosed in this specification is a display unit, a communication unit, a first secondary battery that supplies power to the display unit, and a battery that has a smaller battery capacity than the first secondary battery. 2 secondary battery, first secondary battery remaining amount detecting means, and when the detecting means detects that the remaining amount of the first secondary battery is lower than the threshold power, the power supply destination to the display unit Switching to the second secondary battery, and when using the second secondary battery, the electronic device can communicate at least once by the communication means.

In the above structure, the display unit includes a liquid crystal element and an organic EL element, and the liquid crystal element of the display unit is controlled so that the number of display rewrites per unit time is reduced when the second secondary battery is used. Another feature is to reduce the power consumption of electronic devices.

Moreover, in the said structure, when using a 2nd secondary battery, electric power is ensured by stopping the electric power supply to functional circuits other than a communication means.

In the above configuration, the first secondary battery is configured by a plurality of secondary battery cells.

In addition, it is not limited to the use of a plurality of secondary batteries for one electronic device, and if a single secondary battery is used for one electronic device, a threshold value of the battery is set in advance. It is also possible to make emergency calls as well. For example, when the portable information terminal is used in the normal mode, when the remaining amount of the battery falls below a certain threshold value, the emergency mode is entered. In the emergency mode, the power required for an important function such as an emergency telephone is left in the battery, and other functions are disabled. In the emergency mode, an operation mode with extremely low power consumption is set to such an extent that the battery can be operated even when the remaining amount is not more than the threshold value.

Another structure of the invention disclosed in this specification is a display unit including a liquid crystal element and an organic EL element, a communication unit, a secondary battery that supplies power to the display unit, and a remaining amount of the secondary battery. And a means for disabling or stopping execution of an application that contributes to a change in the display image of the display unit when the detection means detects that the remaining amount of the secondary battery is below the threshold power. The electronic device can communicate at least once by the communication means in a state where the remaining amount of the secondary battery is lower than the threshold power.

In the above configuration, in a state where the remaining amount of the secondary battery is lower than the threshold power, power for emergency communication is ensured as much as possible by stopping the power supply to the functional circuits other than the communication means.

Each of the above structures further includes supply means for charging the secondary battery, and the supply means includes an antenna for wireless power feeding.

Lithium ion storage batteries can be used as they are, but in order to facilitate handling, one or more lithium ion storage batteries are placed inside a container together with a predetermined circuit (such as a charge / discharge control circuit or a protection circuit). It is preferable to store the battery pack in a battery pack or a battery module. A heat insulating material such as glass wool may be provided in the battery pack or battery module for heat insulation.

Battery packs or battery modules are not limited to electronic devices carried by users, but include medical devices, next-generation clean energy vehicles such as hybrid vehicles (HEV), electric vehicles (EV), and plug-in hybrid vehicles (PHEV). Also used for.

A stable communication operation is possible by avoiding a communication failure due to a decrease in the remaining battery level. It is possible to provide a portable information terminal that can reliably secure the power required for at least several calls in an emergency when the battery level is at least.

FIG. 10 is a circuit diagram illustrating one embodiment of the present invention. It is a figure which shows an example of the discharge diagram of a secondary battery. The perspective view which shows an example of a display apparatus. Sectional drawing which shows an example of a display apparatus. Sectional drawing which shows an example of a display apparatus. Sectional drawing which shows an example of a display apparatus. FIG. 10 illustrates an example of a display device and an example of a pixel. FIG. 10 is a circuit diagram illustrating an example of a pixel circuit of a display device. FIG. 6 is a circuit diagram illustrating an example of a pixel circuit of a display device, and a diagram illustrating an example of a pixel. FIG. 6 illustrates a structure of an input / output panel according to an embodiment. FIG. 6 illustrates a structure of an input / output panel according to an embodiment. FIG. 6 is a block diagram illustrating a structure example of a display device and a circuit diagram illustrating an example of a pixel included in the display device. The flow which shows the operation example of a display apparatus. 6 is a timing chart showing an operation example of the display device. FIG. 6 illustrates a configuration example of a display module. FIG. 9 illustrates an example of a power storage device. FIG. 9 illustrates an example of a power storage device. FIG. 9 illustrates an example of a power storage device. FIG. 9 illustrates an example of a power storage device. FIG. 14 illustrates an example of an electronic device. FIG. 14 illustrates an example of an electronic device. The figure explaining the measurement result of the XRD spectrum of a sample. The figure explaining the TEM image of a sample, and an electron beam diffraction pattern. The figure explaining the EDX mapping of a sample.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that modes and details can be variously changed. In addition, the present invention is not construed as being limited to the description of the embodiments below.

(Embodiment 1)
An equivalent circuit diagram showing a part of the configuration of the electronic device is shown in FIG.

As shown in FIG. 1, an electronic apparatus, here, a portable information terminal, uses three normal batteries and one emergency battery.

When the total remaining amount of the three normal-time batteries falls below the first threshold power, the emergency mode is entered. A voltmeter, an ammeter, a wattmeter, or the like can be used as a means for detecting the remaining battery level. FIG. 1 shows an example using a voltmeter.

In the emergency mode, power is supplied from the emergency battery with CTL = “H”. In addition, the power consumption of the entire portable information terminal is reduced. Specifically, the liquid crystal display device is set to IDS driving.

In the case of a hybrid display, only reflective display is used, and application software that is not for emergency use, such as game software, is terminated or not activated. CPU, GPU, controller of liquid crystal display device is normally off drive, that is, a drive method for reducing power consumption by saving power to a non-volatile register and then performing power gating and restarting the operation after restoring the register data; Shall be used. In addition, the portable information terminal needs to periodically transmit the position information to the base station, but this frequency is lowered. When a call signal is received from a base station, or when an emergency call is made from a portable information terminal, a call can be made.

If the remaining amount of the emergency battery is the first power, the remaining power of the battery in the emergency mode is changed from the first power to the fourth threshold power P4 (the emergency battery required for the call). The first power may be set so that the time until the remaining power is reduced to a desired time. The standard of the time is preferably 100 hours or more and 200 hours or less with 72 hours as a standard for saving lives after a disaster occurs. It is also desirable to include power for making calls as many times as necessary. For example, it is desirable that a call can be made 10 times or more and 20 times or less.

Note that a configuration including an emergency battery such as a solar battery or a wireless power feeder and a charging device for charging a normal battery is preferable. With this configuration, even if the remaining amount of the emergency battery is less than the fourth threshold power P4, the remaining emergency battery with the fourth threshold power P4 or higher after a predetermined time has elapsed. It is possible to recover the amount.

Further, the charging device can be configured to charge only the emergency battery. In particular. In the configuration shown in FIG. 1, a switch that can selectively or simultaneously supply the current from the charger to the emergency battery or the regular battery can be provided. With this configuration, the number and frequency of emergency calls can be improved, and the time during which an emergency call can be waited can be lengthened. Furthermore, the charging device can be configured to charge the normal battery and the emergency battery after the emergency battery is charged to the first power level. With such a configuration, other functions of the portable information terminal can be used, and convenience is improved.

(Embodiment 2)
In this embodiment, an example in which one lithium ion secondary battery is used for one electronic device is described.

When the remaining amount of the secondary battery is lower than the first threshold power P1, the emergency mode is entered. For detecting the remaining amount of the secondary battery, a voltmeter, an ammeter, a wattmeter, or the like can be used. Specifically, the first threshold power P1 selection range shown in FIG. 2 is shown. If the voltage of the battery output is less than 3.3 V, some circuits such as LSI may be difficult to operate unless the voltage is raised specifically to generate a power supply voltage. Therefore, the lower limit of the P1 selection range is 3 .3V is suitable. In addition, 5.0 V, 2.5 V, 2.0 V, 1.8 V, 1.2 V, and the like are effective as the lower limit voltage of the other P1 selection range, but can be appropriately determined according to the characteristics of the battery. it can. Further, although the upper limit of the P1 selection range depends on the performance of the lithium ion secondary battery used, for example, in the P1 selection range shown in FIG. If the voltage is set higher than this, there is a risk of erroneous detection that is considered to be lower than the threshold power by a slight voltage fluctuation. In particular, when there is a difference between the batteries, it is considered that the battery has still a sufficient remaining amount and the power is reduced below the first threshold power, which may increase the number of times of charging.

In addition, it is preferable to provide an electronic circuit with an arithmetic circuit that predicts a tendency to decrease the remaining amount in consideration of the usage state by periodically detecting the remaining amount of the battery. During the use of the electronic device, an alarm can be issued to the user because the time predicted to be the P1 selection range of the electronic device is previously determined.

In the emergency mode, the power consumption of the entire portable information terminal is reduced. Specifically, the liquid crystal display device is driven by IDS, and if it is a hybrid display, only reflective display is used, and application software that is not for emergency use, such as game software, is terminated or not permitted to start. The CPU, GPU, and controller of the liquid crystal display device are normally off.

In addition, the portable information terminal needs to periodically transmit the position information to the base station in order to enable a smooth telephone call, but this frequency is lowered. When a call signal is received from a base station, or when an emergency call is made from a portable information terminal, a call can be made.

If the remaining battery level required for at least several calls is the second threshold power P2 (where P1> P2> 0V is satisfied), the remaining battery level is the first threshold value in the emergency mode. What is necessary is just to set 1st threshold power P1 and 2nd threshold power P2 so that time until it falls to 2nd threshold power P2 from electric power P1 can be obtained only for desired time.

Furthermore, a configuration including a solar cell, a wireless power feeding device, and the like is preferable. By adopting such a configuration, even when the remaining amount of the battery becomes less than the second threshold power P2, it is possible to recover the remaining amount of the battery equal to or higher than the second threshold power after a predetermined time has elapsed. .

In the present embodiment, an example of a lithium ion secondary battery is shown, but it is not particularly limited, and a sodium ion secondary battery, a nickel metal hydride battery, an electrochemical capacitor such as an electric double layer capacitor, a redox capacitor, an air battery, etc. May be used.

This embodiment mode can be freely combined with Embodiment Mode 1.

(Embodiment 3)
A configuration example of the display device of this embodiment will be described with reference to FIGS.

<Configuration example 1>
FIG. 3 is a schematic perspective view of the display device 300. The display device 300 has a structure in which a substrate 351 and a substrate 361 are attached to each other. In FIG. 3, the substrate 361 is indicated by a broken line.

  The display device 300 includes a display portion 362, a circuit 364, a wiring 365, and the like. FIG. 3 shows an example in which an IC (integrated circuit) 373 and an FPC 372 are mounted on the display device 300. Therefore, the structure illustrated in FIG. 3 can also be referred to as a display module including the display device 300, an IC, and an FPC.

  As the circuit 364, for example, a scan line driver circuit can be used.

  The wiring 365 has a function of supplying a signal and power to the display portion 362 and the circuit 364. The signal and power are input to the wiring 365 from the outside through the FPC 372 or from the IC 373.

  FIG. 3 illustrates an example in which the IC 373 is provided on the substrate 351 by a COG (Chip On Glass) method, a COF (Chip on Film) method, or the like. For example, an IC having a scan line driver circuit or a signal line driver circuit can be used as the IC 373. Note that the display device 100 and the display module may be configured without an IC. Further, the IC may be mounted on the FPC by a COF method or the like.

  FIG. 4 shows an enlarged view of a part of the display unit 362. In the display portion 362, electrodes 311b included in the plurality of display elements are arranged in a matrix. The electrode 311b has a function of reflecting visible light, and functions as a reflective electrode of the liquid crystal element 180.

  Further, as shown in FIG. 3, the electrode 311 b has an opening 451. Further, the display portion 362 includes the light-emitting element 170 on the substrate 351 side of the electrode 311b. Light from the light emitting element 170 is emitted to the substrate 361 side through the opening 451 of the electrode 311b. The area of the light emitting region of the light emitting element 170 and the area of the opening 451 may be equal. One of the area of the light emitting region of the light emitting element 170 and the area of the opening 451 is larger than the other, which is preferable because a margin for positional deviation is increased. In particular, the area of the opening 451 is preferably larger than the area of the light emitting region of the light emitting element 170. When the opening 451 is small, part of light from the light-emitting element 170 may be blocked by the electrode 311b and may not be extracted to the outside. By making the opening 451 sufficiently large, it is possible to prevent the light emission of the light emitting element 170 from being wasted.

  FIG. 4 illustrates an example of a cross section of the display device 300 illustrated in FIG. 3 when a part of the region including the FPC 372, a part of the region including the circuit 364, and a part of the region including the display portion 362 are cut. Indicates.

  4 includes a transistor 201, a transistor 203, a transistor 205, a transistor 206, a liquid crystal element 180, a light-emitting element 170, an insulating layer 220, a coloring layer 131, a coloring layer 134, and the like between a substrate 351 and a substrate 361. Have The substrate 361 and the insulating layer 220 are bonded via an adhesive layer 141. The substrate 351 and the insulating layer 220 are bonded through an adhesive layer 142.

  The substrate 361 is provided with a coloring layer 131, a light shielding layer 132, an insulating layer 121, an electrode 113 functioning as a common electrode of the liquid crystal element 180, an alignment film 133b, an insulating layer 117, and the like. A polarizing plate 135 is provided on the outer surface of the substrate 361. The insulating layer 121 may function as a planarization layer. Since the surface of the electrode 113 can be substantially flattened by the insulating layer 121, the alignment state of the liquid crystal layer 112 can be made uniform. The insulating layer 117 functions as a spacer for maintaining the cell gap of the liquid crystal element 180. In the case where the insulating layer 117 transmits visible light, the insulating layer 117 may be overlapped with the display region of the liquid crystal element 180.

  The liquid crystal element 180 is a reflective liquid crystal element. The liquid crystal element 180 has a stacked structure in which an electrode 311a functioning as a pixel electrode, a liquid crystal layer 112, and an electrode 113 are stacked. An electrode 311b that reflects visible light is provided in contact with the substrate 351 side of the electrode 311a. The electrode 311b has an opening 451. The electrode 311a and the electrode 113 transmit visible light. An alignment film 133a is provided between the liquid crystal layer 112 and the electrode 311a. An alignment film 133 b is provided between the liquid crystal layer 112 and the electrode 113.

  In the liquid crystal element 180, the electrode 311b has a function of reflecting visible light, and the electrode 113 has a function of transmitting visible light. Light incident from the substrate 361 side is polarized by the polarizing plate 135, passes through the electrode 113 and the liquid crystal layer 112, and is reflected by the electrode 311b. Then, the light passes through the liquid crystal layer 112 and the electrode 113 again and reaches the polarizing plate 135. At this time, the alignment of the liquid crystal can be controlled by the voltage applied between the electrode 311b and the electrode 113, and the optical modulation of light can be controlled. That is, the intensity of light emitted through the polarizing plate 135 can be controlled. In addition, light that is not in a specific wavelength region is absorbed by the colored layer 131, so that the extracted light is, for example, red light.

  As shown in FIG. 4, the opening 451 is preferably provided with an electrode 311a that transmits visible light. Thereby, since the liquid crystal layer 112 is aligned in the region overlapping with the opening 451 as well as the other regions, it is possible to suppress the occurrence of unintentional light leakage due to poor alignment of the liquid crystal at the boundary between these regions. .

  In the connection portion 207, the electrode 311b is electrically connected to the conductive layer 222a included in the transistor 206 through the conductive layer 221b. The transistor 206 has a function of controlling driving of the liquid crystal element 180.

  As the liquid crystal element 180, liquid crystal elements to which various modes are applied can be used. As the liquid crystal material, either a positive type liquid crystal or a negative type liquid crystal may be used, and an optimal liquid crystal material may be used according to an applied mode or design. An alignment film can be provided to control the alignment of the liquid crystal.

  Note that in the case where a reflective liquid crystal element is used as the liquid crystal element 180, a polarizing plate 135 may be provided on the display surface side. In addition to the polarizing plate 135, it is preferable to dispose a light diffusing plate on the display surface side because the visibility can be improved.

  Note that a front light may be provided outside the polarizing plate 135. As the front light, an edge light type front light is preferably used. It is preferable to use a front light including an LED (Light Emitting Diode) because power consumption can be reduced.

Alternatively, the liquid crystal element 180 may be driven using a guest / host liquid crystal mode. Thereby, a reflective display panel can be provided without using a polarizing plate. Alternatively, the display on the display panel can be brightened. Guest-host liquid crystal refers to a liquid crystal material containing a dichroic dye. Specifically, a material having a large absorbance in the major axis direction of a molecule and a small absorbance in a minor axis direction orthogonal to the major axis direction can be used for the dichroic dye. Preferably, a material having a dichroic ratio of 10 or more can be used for the dichroic dye, and more preferably, a material having a dichroic ratio of 20 or more can be used for the dichroic dye.

For example, azo dyes, anthraquinone dyes, dioxazine dyes, and the like can be used as dichroic dyes.

Further, a structure in which two liquid crystal layers containing homogeneously aligned dichroic dyes are stacked so that the alignment directions are orthogonal to each other can be used for the layer containing the liquid crystal material. Thereby, light can be easily absorbed in all directions. Alternatively, contrast can be increased.

In addition, a structure in which phase transition type guest-host liquid crystal or droplets containing guest-host liquid crystal are dispersed in a polymer can be used for the liquid crystal layer of the liquid crystal element 180.

  A connection portion 252 is provided in a part of the region where the adhesive layer 141 is provided. In the connection portion 252, a conductive layer obtained by processing the same conductive film as the electrode 311 a and a part of the electrode 113 are electrically connected by a connection body 243. Therefore, a signal or a potential input from the FPC 372 connected to the substrate 351 side can be supplied to the electrode 113 formed on the substrate 361 side through the connection portion 252.

  As the connection body 243, for example, conductive particles can be used. Moreover, the connection body 243 may become a shape crushed in the up-down direction as shown in FIG. By being crushed in the vertical direction, the contact area between the connection body 243 and the conductive layer electrically connected to the connection body 243 can be increased, the contact resistance can be reduced, and the occurrence of defects such as poor connection can be suppressed. be able to.

  The connection body 243 is preferably disposed so as to be covered with the adhesive layer 141. For example, the connection body 243 may be disposed after applying a paste or the like to be the adhesive layer 141.

  The light emitting element 170 is a bottom emission type light emitting element. The light-emitting element 170 has a stacked structure in which an electrode 191 that functions as a pixel electrode, an EL layer 192, and an electrode 193 that functions as a common electrode are stacked in this order from the insulating layer 220 side. The electrode 191 is connected to the conductive layer 222 b included in the transistor 205 through an opening provided in the insulating layer 214. The transistor 205 has a function of controlling driving of the light-emitting element 170. An insulating layer 216 covers the end portion of the electrode 191. The electrode 193 includes a material that reflects visible light, and the electrode 191 includes a material that transmits visible light. An insulating layer 194 is provided to cover the electrode 193. Light emitted from the light-emitting element 170 is emitted to the substrate 361 side through the coloring layer 134, the insulating layer 220, the opening 451, the electrode 311a, and the like.

  The liquid crystal element 180 and the light emitting element 170 can exhibit various colors by changing the color of the colored layer depending on the pixel. The display device 300 can perform color display using the liquid crystal element 180. The display device 300 can perform color display using the light-emitting element 170.

  The circuit electrically connected to the liquid crystal element 180 is preferably formed on the same plane as the circuit electrically connected to the light emitting element 170. Thereby, the thickness of the display device can be reduced as compared with the case where the two circuits are formed on different surfaces. Further, since the two transistors can be manufactured in the same process, the manufacturing process can be simplified as compared with the case where the two transistors are formed over different surfaces.

  The pixel electrode of the liquid crystal element 180 has position information opposite to the pixel electrode of the light-emitting element 170 with a gate insulating layer included in the transistor interposed therebetween.

  Here, the liquid crystal element 180 is used when a transistor 206 having a metal oxide in a channel formation region and having extremely low off-state current or a memory element electrically connected to the transistor 206 is used. Thus, even when the writing operation to the pixel is stopped when displaying a still image, the gradation can be maintained. That is, display can be maintained even if the frame rate is extremely small. In one embodiment of the present invention, the frame rate can be extremely small, and driving with low power consumption can be performed.

[Metal oxide]
Here, the transistor 206 which has a metal oxide in a channel formation region and has extremely low off-state current is described. As the metal oxide used for the channel formation region, a metal oxide that functions as an oxide semiconductor (hereinafter also referred to as an oxide semiconductor) is preferably used.

  The oxide semiconductor preferably contains at least indium or zinc. In particular, it is preferable to contain indium and zinc. In addition to these, it is preferable that aluminum, gallium, yttrium, tin, or the like is contained. Further, one or more selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, or the like may be included.

  Here, a case where the oxide semiconductor is InMZnO containing indium, the element M, and zinc is considered. The element M is aluminum, gallium, yttrium, tin, or the like. Other elements applicable to the element M include boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium. However, the element M may be a combination of a plurality of the aforementioned elements.

  Note that in this specification and the like, metal oxides containing nitrogen may be collectively referred to as metal oxides. Further, a metal oxide containing nitrogen may be referred to as a metal oxynitride.

<Composition of metal oxide>
A structure of a CAC (Cloud-Aligned Composite) -OS that can be used for the transistor disclosed in one embodiment of the present invention is described below.

In this specification and the like, a metal oxide is a metal oxide in a broad expression. Metal oxides are classified into oxide insulators, oxide conductors (including transparent oxide conductors), oxide semiconductors (also referred to as oxide semiconductors or simply OS), and the like. For example, when a metal oxide is used for an active layer of a transistor, the metal oxide may be referred to as an oxide semiconductor. That is, in the case of describing as an OS FET, it can be said to be a transistor including a metal oxide or an oxide semiconductor.

In this specification, in the case where a metal oxide region in which a region having a conductor function and a region having a dielectric function are mixed and the entire metal oxide functions as a semiconductor, a CAC (Cloud-Aligned Composite) − It is defined as OS (Oxide Semiconductor) or CAC-metal oxide.

In other words, the CAC-OS is one structure of a material in which an element included in an oxide semiconductor is unevenly distributed with a size of 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm, or the vicinity thereof. . Note that in the following, in an oxide semiconductor, one or more elements are unevenly distributed, and a region including the element has a size of 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm, or the vicinity thereof. The state mixed with is also referred to as a mosaic or patch.

The physical characteristics of a region where a specific element is unevenly distributed are determined by the properties of the element. For example, a region in which elements that tend to become insulators are relatively uneven among the elements constituting the metal oxide is a dielectric region. On the other hand, a region in which elements that tend to be conductors are relatively uneven among the elements constituting the metal oxide is a conductor region. In addition, when the conductor region and the dielectric region are mixed in a mosaic, the material functions as a semiconductor.

That is, the metal oxide in one embodiment of the present invention is a kind of matrix composite or metal matrix composite in which materials having different physical characteristics are mixed.

Note that the oxide semiconductor preferably contains at least indium. In particular, it is preferable to contain indium and zinc. In addition to them, element M (M is gallium, aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum. , One or more selected from tungsten, magnesium, or the like.

For example, a CAC-OS in In-Ga-Zn oxide (In-Ga-Zn oxide among CAC-OSs may be referred to as CAC-IGZO in particular) is an indium oxide (hereinafter referred to as InO). _X1 (X1 is greater real than 0) and.), or indium zinc oxide _{(hereinafter, in X2 Zn Y2 O Z2 (} X2, Y2, and Z2 is larger real than 0) and a.), gallium An oxide (hereinafter referred to as GaO _X3 (X3 is a real number greater than 0)) or a gallium zinc oxide (hereinafter referred to as Ga _X4 Zn _Y4 O _Z4 (where X4, Y4, and Z4 are greater than 0)) to.) and the like, the material becomes mosaic by separate into, mosaic _{InO X1} or _in X2 _Zn Y2 _{O Z2,} is a configuration in which uniformly distributed in the film (hereinafter Also referred to as a cloud-like.) A.

That, CAC-OS includes a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2,} or _{InO X1} is the main component region is a composite oxide semiconductor having a structure that is mixed. Note that in this specification, for example, the first region indicates that the atomic ratio of In to the element M in the first region is larger than the atomic ratio of In to the element M in the second region. It is assumed that the concentration of In is higher than that in the second region.

Note that IGZO is a common name and may refer to one compound of In, Ga, Zn, and O. As a typical example, InGaO ₃ (ZnO) _m1 (m1 is a natural number) or In _{(1 + x0)} Ga _(1-x0) O ₃ (ZnO) _m0 (−1 ≦ x0 ≦ 1, m0 is an arbitrary number) A crystalline compound may be mentioned.

The crystalline compound has a single crystal structure, a polycrystalline structure, or a CAAC structure. The CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have c-axis orientation and are connected without being oriented in the ab plane.

On the other hand, CAC-OS relates to a material structure of an oxide semiconductor. CAC-OS refers to a nanoparticulate region mainly composed of Ga and partly composed of In, in a material configuration containing In, Ga, Zn, and O. Are observed, each of which is randomly dispersed in a mosaic pattern. Therefore, in the CAC-OS, the crystal structure is a secondary element.

Note that the CAC-OS does not include a stacked structure of two or more kinds of films having different compositions. For example, a structure composed of two layers of a film mainly containing In and a film mainly containing Ga is not included.

Incidentally, a region _{GaO X3} is the main _component, and In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component region, in some cases clear boundary can not be observed.

In addition, instead of gallium, aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium are selected. In the case where one or a plurality of types are included, in the CAC-OS, a nanoparticulate region mainly containing the element is observed in part, and a nanoparticulate region mainly containing In is partly observed. Are observed, each of which is randomly dispersed in a mosaic pattern.

<Analysis of CAC-OS>
Subsequently, the results of measurement of an oxide semiconductor film formed on a substrate using various measurement methods will be described.

<< Sample structure and production method >>
In the following, nine samples according to one embodiment of the present invention are described. Each sample is manufactured under different conditions for the substrate temperature and the oxygen gas flow rate when the oxide semiconductor film is formed. Note that the sample has a structure including a substrate and an oxide semiconductor over the substrate.

A method for manufacturing each sample will be described.

First, a glass substrate is used as the substrate. Subsequently, an In—Ga—Zn oxide with a thickness of 100 nm is formed as an oxide semiconductor over the glass substrate with a sputtering apparatus. The deposition conditions are such that the pressure in the chamber is 0.6 Pa and an oxide target (In: Ga: Zn = 4: 2: 4.1 [atomic ratio]) is used as the target. In addition, 2500 W AC power is supplied to the oxide target installed in the sputtering apparatus.

Note that the substrate temperature was set to a temperature at which the substrate was not intentionally heated (hereinafter also referred to as room temperature or RT), 130 ° C., or 170 ° C. as a condition for forming the oxide film. In addition, nine samples are manufactured by setting the flow rate ratio of oxygen gas to the mixed gas of Ar and oxygen (hereinafter also referred to as oxygen gas flow rate ratio) to 10%, 30%, or 100%.

≪Analysis by X-ray diffraction≫
In this item, the results of X-ray diffraction (XRD) measurement on nine samples will be described. Note that Bruker D8 ADVANCE was used as the XRD apparatus. The condition is that the scanning range is 15 deg. In θ / 2θ scanning by the out-of-plane method. To 50 deg. , The step width is 0.02 deg. The scanning speed is 3.0 deg. / Min.

FIG. 22 shows the results of measuring the XRD spectrum using the out-of-plane method. In FIG. 22, the measurement results for the sample with the substrate temperature condition of 170 ° C. during film formation are shown in the upper row, the measurement results for the sample with the substrate temperature condition of 130 ° C. during film formation are shown in the middle row, and the film formation is shown in the lower row. The substrate temperature condition of R.R. T.A. The measurement result in the sample is shown. The left column shows the measurement results for the sample with an oxygen gas flow ratio of 10%, the center column shows the measurement results for a sample with an oxygen gas flow ratio of 30%, and the right column shows the oxygen gas flow rate. The measurement result in the sample whose ratio condition is 100% is shown.

In the XRD spectrum shown in FIG. 22, the peak intensity near 2θ = 31 ° is increased by increasing the substrate temperature during film formation or increasing the ratio of the oxygen gas flow rate ratio during film formation. Note that the peak near 2θ = 31 ° is a crystalline IGZO compound (also referred to as CAAC (c-axis aligned crystalline) -IGZO) oriented in the c-axis with respect to a surface to be formed or an upper surface substantially perpendicular to the surface. Is known to originate from

In the XRD spectrum shown in FIG. 22, a clear peak did not appear as the substrate temperature during film formation was lower or the oxygen gas flow ratio was smaller. Therefore, it can be seen that the sample having a low substrate temperature during film formation or a small oxygen gas flow ratio does not show orientation in the ab plane direction and c-axis direction of the measurement region.

≪Analysis with electron microscope≫
In this item, the substrate temperature R.D. T.A. Samples prepared at a gas flow rate ratio of 10% and HAADF (High-Angle Angular Dark Field) -STEM (Scanning Transmission Electron Microscope) will be described and explained below (hereinafter obtained by HAADF-STEM). The image is also called a TEM image.)

The results of image analysis of a planar image (hereinafter also referred to as a planar TEM image) acquired by HAADF-STEM and a sectional image (hereinafter also referred to as a sectional TEM image) will be described. The TEM image was observed using a spherical aberration correction function. The HAADF-STEM image was taken by irradiating an electron beam with an acceleration voltage of 200 kV and a beam diameter of about 0.1 nmφ using an atomic resolution analytical electron microscope JEM-ARM200F manufactured by JEOL Ltd.

FIG. 23A shows the substrate temperature R.D. T.A. , And a plane TEM image of a sample fabricated at an oxygen gas flow rate ratio of 10%. FIG. 23B shows the substrate temperature R.D. T.A. And a cross-sectional TEM image of a sample manufactured at an oxygen gas flow rate ratio of 10%.

≪Analysis of electron diffraction pattern≫
In this item, the substrate temperature R.D. T.A. The result of acquiring an electron beam diffraction pattern by irradiating an electron beam having a probe diameter of 1 nm (also referred to as a nanobeam electron beam) to a sample manufactured at an oxygen gas flow rate ratio of 10% will be described.

As shown in FIG. 23A, the substrate temperature R.D. T.A. , And an electron beam diffraction pattern indicated by black spots a1, black spots a2, black spots a3, black spots a4, and black spots a5 in a planar TEM image of a sample prepared at an oxygen gas flow rate ratio of 10%. The observation of the electron beam diffraction pattern is performed while moving at a constant speed from the 0 second position to the 35 second position while irradiating the electron beam. FIG. 23C shows the result of black point a1, FIG. 23D shows the result of black point a2, FIG. 23E shows the result of black point a3, FIG. 23F shows the result of black point a4, and FIG. As shown in FIG.

From FIG. 23C, FIG. 23D, FIG. 23E, FIG. 23F, and FIG. 23G, a high-luminance region can be observed so as to draw a circle (in a ring shape). A plurality of spots can be observed in the ring-shaped region.

In addition, as shown in FIG. T.A. In the cross-sectional TEM image of the sample manufactured at an oxygen gas flow rate ratio of 10%, the electron beam diffraction pattern indicated by black spot b1, black spot b2, black spot b3, black spot b4, and black spot b5 is observed. FIG. 23H shows the result of black point b1, FIG. 23I shows the result of black point b2, FIG. 23J shows the result of black point b3, FIG. 23K shows the result of black point b4, and FIG. As shown in FIG.

From FIG. 23 (H), FIG. 23 (I), FIG. 23 (J), FIG. 23 (K), and FIG. A plurality of spots can be observed in the ring-shaped region.

Here, for example, when an electron beam with a probe diameter of 300 nm is incident on a CAAC-OS having an InGaZnO ₄ crystal in parallel to the sample surface, spots resulting from the (009) plane of the InGaZnO ₄ crystal are included. A diffraction pattern is seen. That is, it can be seen that the CAAC-OS has c-axis orientation and the c-axis is in a direction substantially perpendicular to the formation surface or the top surface. On the other hand, when an electron beam with a probe diameter of 300 nm is incident on the same sample perpendicularly to the sample surface, a ring-shaped diffraction pattern is confirmed. That is, in the CAAC-OS, the a-axis and the b-axis do not have orientation.

Further, when electron beam diffraction using an electron beam with a large probe diameter (for example, 50 nm or more) is performed on an oxide semiconductor having microcrystals (hereinafter referred to as nc-OS), a halo pattern is obtained. A simple diffraction pattern is observed. Further, when nanobeam electron diffraction is performed on the nc-OS using an electron beam with a small probe diameter (for example, less than 50 nm), bright spots (spots) are observed. Further, when nanobeam electron diffraction is performed on the nc-OS, a region with high luminance may be observed so as to draw a circle (in a ring shape). In addition, a plurality of bright spots may be observed in the ring-shaped region.

Substrate temperature R.D. T.A. The electron beam diffraction pattern of a sample manufactured at an oxygen gas flow rate ratio of 10% has a ring-like high luminance region and a plurality of bright spots in the ring region. Therefore, the substrate temperature R.D. T.A. And the sample manufactured at an oxygen gas flow rate ratio of 10% has an electron beam diffraction pattern of nc-OS and has no orientation in the plane direction and the cross-sectional direction.

As described above, an oxide semiconductor with a low substrate temperature or a low oxygen gas flow ratio during deposition has properties that are clearly different from those of an amorphous oxide semiconductor film and a single crystal oxide semiconductor film. Can be estimated.

≪Elemental analysis≫
In this item, by using energy dispersive X-ray spectroscopy (EDX) and obtaining and evaluating EDX mapping, the substrate temperature R.D. T.A. The results of elemental analysis of a sample prepared at an oxygen gas flow rate ratio of 10% will be described. For EDX measurement, an energy dispersive X-ray analyzer JED-2300T manufactured by JEOL Ltd. is used as an element analyzer. A Si drift detector is used to detect X-rays emitted from the sample.

In the EDX measurement, each point in the analysis target region of the sample is irradiated with an electron beam, and the characteristic X-ray energy and the number of occurrences of the sample generated thereby are measured to obtain an EDX spectrum corresponding to each point. In this embodiment, the peak of the EDX spectrum at each point is represented by the electron transition from the In atom to the L shell, the electron transition from the Ga atom to the K shell, the electron transition from the Zn atom to the K shell, and the K shell from the O atom. And the ratio of each atom at each point is calculated. By performing this for the analysis target region of the sample, EDX mapping showing the distribution of the ratio of each atom can be obtained.

FIG. 24 shows the substrate temperature R.D. T.A. And EDX mapping in a cross section of a sample fabricated at an oxygen gas flow rate ratio of 10%. FIG. 24A is an EDX mapping of Ga atoms (the ratio of Ga atoms to all atoms is in the range of 1.18 to 18.64 [atomic%]). FIG. 24B is an EDX mapping of In atoms (the ratio of In atoms to all atoms is in the range of 9.28 to 33.74 [atomic%]). FIG. 24C is an EDX mapping of Zn atoms (the ratio of Zn atoms to all atoms is in the range of 6.69 to 24.99 [atomic%]). 24A, 24B, and 24C show the substrate temperature R.D. during film formation. T.A. In a cross section of a sample manufactured at an oxygen gas flow rate ratio of 10%, a region in the same range is shown. Note that the EDX mapping shows the ratio of elements in light and dark so that the more measurement elements in the range, the brighter the brightness, and the darker the measurement elements. The magnification of EDX mapping shown in FIG. 24 is 7.2 million times.

In the EDX mapping shown in FIGS. 24A, 24B, and 24C, a relative light / dark distribution is seen in the image, and the substrate temperature R.D. T.A. In the sample prepared at an oxygen gas flow rate ratio of 10%, it can be confirmed that each atom exists in a distributed manner. Here, attention is focused on a range surrounded by a solid line and a range surrounded by a broken line in FIGS. 24 (A), 24 (B), and 24 (C).

In FIG. 24A, the range surrounded by the solid line includes many relatively dark regions, and the range surrounded by the broken line includes many relatively bright regions. In FIG. 24B, a range surrounded by a solid line includes many relatively bright areas, and a range surrounded by a broken line includes many relatively dark areas.

That is, the range surrounded by the solid line is a region having a relatively large number of In atoms, and the range surrounded by a broken line is a region having a relatively small number of In atoms. Here, in FIG. 24C, the right side is a relatively bright region and the left side is a relatively dark region in the range surrounded by the solid line. Therefore, the range surrounded by the solid line is a region mainly composed of In _X2 Zn _Y2 O _Z2 or InO _X1 .

A range surrounded by a solid line is a region with relatively few Ga atoms, and a range surrounded by a broken line is a region with relatively many Ga atoms. In FIG. 24C, in the range surrounded by the broken line, the upper left region is a relatively bright region, and the lower right region is a relatively dark region. Therefore, the range surrounded by the broken line is a region whose main component is GaO _X3 , Ga _X4 Zn _Y4 O _Z4 , or the like.

24A, 24B, and 24C, the distribution of In atoms is relatively more uniform than Ga atoms, and InO _X1 is the main component. The regions appear to be connected to each other through a region mainly composed of In _X2 Zn _Y2 O _Z2 . As described above, the region mainly composed of In _X2 Zn _Y2 O _Z2 or InO _X1 is formed so as to spread in a cloud shape.

Thus, the region which is the main component such as _{GaO X3, In X2 Zn Y2 O} Z2 or _{InO X1} there is a region which is a main component, ubiquitously, an In-Ga-Zn oxide having a mixed to have the structure Things can be referred to as CAC-OS.

The crystal structure in the CAC-OS has an nc structure. The nc structure of CAC-OS has several bright spots (spots) in addition to bright spots (spots) caused by IGZO including single crystal, polycrystal, or CAAC structure in the electron diffraction image. Have. Alternatively, in addition to several bright spots (spots), a crystal structure is defined as a region having a high brightness in a ring shape.

Further, FIG. 24 (A), FIG. 24 (B), and 24 from (C), such as _{GaO X3} is the main component area, and _In X2 _Zn Y2 _{O Z2} or _{InO X1} is a region which is the main component, The size is observed from 0.5 nm to 10 nm, or from 1 nm to 3 nm. Preferably, in EDX mapping, the diameter of a region in which each element is a main component is 1 nm or more and 2 nm or less.

As described above, the CAC-OS has a structure different from that of the IGZO compound in which the metal elements are uniformly distributed and has properties different from those of the IGZO compound. That is, in the CAC-OS, a region in which GaO _X3 or the like is a main component and a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component are phase-separated from each other, and a region in which each element is a main component. Has a mosaic structure.

Here, the region containing In _X2 Zn _Y2 O _Z2 or InO _X1 as a main component is a region having higher conductivity than a region containing GaO _X3 or the like as a main component. _That, In _{X2 Zn} Y2 _{O Z2} or _{InO X1,} is an area which is the main component, by carriers flow, expressed the conductivity of the oxide semiconductor. Accordingly, a region where In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component is distributed in a cloud shape in the oxide semiconductor, whereby high field-effect mobility (μ) can be realized.

On the other hand, areas such as _{GaO X3} is the main _component, as compared to the In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component area, it is highly regions insulating. That is, a region containing GaO _X3 or the like as a main component is distributed in the oxide semiconductor, whereby leakage current can be suppressed and good switching operation can be realized.

Therefore, when CAC-OS is used for a semiconductor element, the insulating property caused by GaO _{X3 and the} like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1 act in a complementary manner, resulting in high An on-current (I _on ) and high field effect mobility (μ) can be realized.

In addition, a semiconductor element using a CAC-OS has high reliability. Therefore, the CAC-OS is optimal for various semiconductor devices including a display.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

[Transistor having oxide semiconductor]
Next, the case where the above oxide semiconductor is used for a transistor is described.

  Note that by using the oxide semiconductor for a transistor, a transistor with high field-effect mobility can be realized. In addition, a highly reliable transistor can be realized.

For the transistor, an oxide semiconductor with low carrier density is preferably used. In the case where the carrier density of the oxide semiconductor film is decreased, the impurity concentration in the oxide semiconductor film may be decreased and the defect level density may be decreased. In this specification and the like, a low impurity concentration and a low density of defect states are referred to as high purity intrinsic or substantially high purity intrinsic. For example, the oxide semiconductor has a carrier density of less than 8 × 10 ¹¹ / cm ³ , preferably less than 1 × 10 ¹¹ / cm ³ , more preferably less than 1 × 10 ¹⁰ / cm ³ , and 1 × 10 ⁻⁹ / What is necessary is just to be cm ³ or more.

  In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and thus may have a low density of trap states.

  In addition, the charge trapped in the trap level of the oxide semiconductor takes a long time to disappear, and may behave as if it were a fixed charge. Therefore, a transistor in which a channel region is formed in an oxide semiconductor with a high trap state density may have unstable electrical characteristics.

  Therefore, in order to stabilize the electrical characteristics of the transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. In order to reduce the impurity concentration in the oxide semiconductor, it is preferable to reduce the impurity concentration in an adjacent film. Impurities include hydrogen, nitrogen, alkali metal, alkaline earth metal, iron, nickel, silicon, and the like.

<Impurity>
Here, the influence of each impurity in the oxide semiconductor is described.

In the oxide semiconductor, when silicon or carbon which is one of Group 14 elements is included, a defect level is formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon in the vicinity of the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are 2 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁷ atoms / cm ³ or less.

In addition, when the oxide semiconductor contains an alkali metal or an alkaline earth metal, a defect level is formed and carriers may be generated in some cases. Therefore, a transistor including an oxide semiconductor containing an alkali metal or an alkaline earth metal is likely to be normally on. Therefore, it is preferable to reduce the concentration of alkali metal or alkaline earth metal in the oxide semiconductor. Specifically, the concentration of alkali metal or alkaline earth metal in the oxide semiconductor obtained by SIMS is set to 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁶ atoms / cm ³ or less.

In addition, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier density is increased, and the oxide semiconductor is likely to be n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor is likely to be normally on. Accordingly, nitrogen in the oxide semiconductor is preferably reduced as much as possible. For example, the nitrogen concentration in the oxide semiconductor is less than 5 × 10 ¹⁹ atoms / cm ^{3 in} SIMS, preferably 5 × 10 ^18. atoms / cm ³ or less, more preferably 1 × 10 ¹⁸ atoms / cm ³ or less, and even more preferably 5 × 10 ¹⁷ atoms / cm ³ or less.

In addition, hydrogen contained in the oxide semiconductor reacts with oxygen bonded to a metal atom to become water, so that an oxygen vacancy may be formed in some cases. When hydrogen enters the oxygen vacancies, electrons serving as carriers may be generated. In addition, a part of hydrogen may be combined with oxygen bonded to a metal atom to generate electrons as carriers. Therefore, a transistor including an oxide semiconductor containing hydrogen is likely to be normally on. For this reason, it is preferable that hydrogen in the oxide semiconductor be reduced as much as possible. Specifically, in an oxide semiconductor, the hydrogen concentration obtained by SIMS is less than 1 × 10 ²⁰ atoms / cm ³ , preferably less than 1 × 10 ¹⁹ atoms / cm ³ , more preferably 5 × 10 ¹⁸ atoms / cm 3. Less than ³ , more preferably less than 1 × 10 ¹⁸ atoms / cm ³ .

  By using an oxide semiconductor in which impurities are sufficiently reduced for the channel region of the transistor, stable electrical characteristics can be imparted.

  The transistor 203 is a transistor (also referred to as a switching transistor or a selection transistor) that controls pixel selection / non-selection. The transistor 205 is a transistor (also referred to as a drive transistor) that controls a current flowing through the light-emitting element 170.

  Insulating layers such as an insulating layer 211, an insulating layer 212, an insulating layer 213, and an insulating layer 214 are provided on the substrate 351 side of the insulating layer 220. A part of the insulating layer 211 functions as a gate insulating layer of each transistor. The insulating layer 212 is provided so as to cover the transistor 206 and the like. The insulating layer 213 is provided so as to cover the transistor 205 and the like. The insulating layer 214 functions as a planarization layer. Note that the number of insulating layers covering the transistor is not limited, and may be a single layer or two or more layers.

  It is preferable to use a material in which impurities such as water and hydrogen hardly diffuse for at least one of the insulating layers covering each transistor. Thereby, the insulating layer can function as a barrier film. With such a structure, impurities can be effectively prevented from diffusing from the outside with respect to the transistor, and a highly reliable display device can be realized.

  The transistor 201, the transistor 203, the transistor 205, and the transistor 206 include a conductive layer 221a that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, a conductive layer 222a and a conductive layer 222b that function as a source and a drain, and a semiconductor layer 231. Here, the same hatching pattern is given to a plurality of layers obtained by processing the same conductive film.

  In addition to the structures of the transistor 203 and the transistor 206, the transistor 201 and the transistor 205 include a conductive layer 223 that functions as a gate.

  A structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates is applied to the transistor 201 and the transistor 205. With such a structure, the threshold voltage of the transistor can be controlled. The transistor may be driven by connecting two gates and supplying the same signal thereto. Such a transistor can have higher field-effect mobility than other transistors, and can increase on-state current. As a result, a circuit that can be driven at high speed can be manufactured. Furthermore, the area occupied by the circuit portion can be reduced. By applying a transistor with a large on-state current, even if the number of wirings increases when the display device is enlarged or high-definition, signal delay in each wiring can be reduced, and display unevenness is suppressed. can do.

  Alternatively, the threshold voltage of the transistor can be controlled by applying a potential for controlling the threshold voltage to one of the two gates and applying a potential for driving to the other of the two gates.

  There is no limitation on the structure of the transistor included in the display device. The transistor included in the circuit 364 and the transistor included in the display portion 362 may have the same structure or different structures. The plurality of transistors included in the circuit 364 may have the same structure, or two or more structures may be used in combination. Similarly, the plurality of transistors included in the display portion 362 may have the same structure, or two or more structures may be used in combination.

  A colored layer 134 is provided in contact with the insulating layer 213. The colored layer 134 is covered with the insulating layer 214.

  A connection portion 204 is provided in a region of the substrate 351 that does not overlap with the substrate 361. In the connection portion 204, the wiring 365 is electrically connected to the FPC 372 through the connection layer 242. The connection unit 204 has the same configuration as the connection unit 207. On the upper surface of the connection portion 204, a conductive layer obtained by processing the same conductive film as the electrode 311a is exposed. Accordingly, the connection unit 204 and the FPC 372 can be electrically connected via the connection layer 242.

  A linear polarizing plate may be used as the polarizing plate 135 disposed on the outer surface of the substrate 361, but a circular polarizing plate may also be used. As a circularly-polarizing plate, what laminated | stacked the linearly-polarizing plate and the quarter wavelength phase difference plate, for example can be used. Thereby, external light reflection can be suppressed. In addition, a desired contrast may be realized by adjusting a cell gap, an alignment, a driving voltage, and the like of the liquid crystal element used for the liquid crystal element 180 in accordance with the type of the polarizing plate.

Various optical members can be arranged outside the substrate 361. Examples of the optical member include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an antireflection layer, and a light collecting film. A material in which an antireflection film having a thickness of 1 μm or less, for example, is formed on the outside of the substrate 361 can be used for the substrate 361. Specifically, a material obtained by stacking three or more dielectric layers, preferably five or more layers, more preferably 15 or more layers can be used for the substrate 361. Thereby, the reflectance can be suppressed to 1% or less, preferably 0.3% or less.

Further, on the outside of the substrate 361, an antistatic film that suppresses adhesion of dust, a water-repellent film that makes it difficult to adhere dirt, a hard coat film that suppresses generation of scratches due to use, and the like may be arranged.

<Configuration example 2>
A display device 300A illustrated in FIG. 5 is different from the display device 300 mainly in that it does not include the transistor 201, the transistor 203, the transistor 205, and the transistor 206 but includes the transistor 281, the transistor 284, the transistor 285, and the transistor 286. .

  In FIG. 5, the positions of the insulating layer 117, the connection portion 207, and the like are also different from those in FIG. FIG. 5 illustrates an end portion of the pixel. The insulating layer 117 is disposed so as to overlap the end portion of the colored layer 131. Further, the insulating layer 117 is disposed so as to overlap the end portion of the light shielding layer 132. As described above, the insulating layer may be disposed in a portion that does not overlap the display region (portion that overlaps the light shielding layer 132).

  Like the transistor 284 and the transistor 285, two transistors included in the display device may be partially stacked. Thereby, since the area occupied by the pixel circuit can be reduced, the definition can be increased. In addition, the light emitting area of the light emitting element 170 can be increased and the aperture ratio can be improved. If the light-emitting element 170 has a high aperture ratio, the current density for obtaining necessary luminance can be reduced, so that reliability is improved.

  The transistor 281, the transistor 284, and the transistor 286 each include a conductive layer 221a, an insulating layer 211, a semiconductor layer 231, a conductive layer 222a, and a conductive layer 222b. The conductive layer 221a overlaps with the semiconductor layer 231 with the insulating layer 211 interposed therebetween. The conductive layer 222 a and the conductive layer 222 b are electrically connected to the semiconductor layer 231. The transistor 281 includes a conductive layer 223.

  The transistor 285 includes a conductive layer 222b, an insulating layer 217, a semiconductor layer 261, a conductive layer 223, an insulating layer 212, an insulating layer 213, a conductive layer 263a, and a conductive layer 263b. The conductive layer 222b overlaps with the semiconductor layer 261 with the insulating layer 217 interposed therebetween. The conductive layer 223 overlaps with the semiconductor layer 261 with the insulating layer 212 and the insulating layer 213 interposed therebetween. The conductive layer 263a and the conductive layer 263b are electrically connected to the semiconductor layer 261.

  The conductive layer 221a functions as a gate. The insulating layer 211 functions as a gate insulating layer. The conductive layer 222a functions as one of a source and a drain. The conductive layer 222b included in the transistor 286 functions as the other of the source and the drain.

  The conductive layer 222b shared by the transistor 284 and the transistor 285 includes a portion functioning as the other of the source and the drain of the transistor 284 and a portion functioning as the gate of the transistor 285. The insulating layer 217, the insulating layer 212, and the insulating layer 213 function as gate insulating layers. One of the conductive layer 263a and the conductive layer 263b functions as a source, and the other functions as a drain. The conductive layer 223 functions as a gate.

<Configuration Example 3> FIG. 6 shows a cross-sectional view of a display portion of the display device 300B.

  A display device 300B illustrated in FIG. 6 includes a transistor 40, a transistor 80, a liquid crystal element 180, a light-emitting element 170, an insulating layer 220, a coloring layer 131, a coloring layer 134, and the like between a substrate 351 and a substrate 361.

  In the liquid crystal element 180, the external light is reflected by the electrode 311b, and the reflected light is emitted to the substrate 361 side. The light emitting element 170 emits light to the substrate 361 side. For the structures of the liquid crystal element 180 and the light emitting element 170, Structure Example 1 can be referred to.

  The substrate 361 is provided with a coloring layer 131, an insulating layer 121, an electrode 113 functioning as a common electrode of the liquid crystal element 180, and an alignment film 133b.

  The liquid crystal layer 112 is sandwiched between the electrode 311a and the electrode 113 through the alignment film 133a and the alignment film 133b.

  The transistor 40 is covered with an insulating layer 212 and an insulating layer 213. The insulating layer 213 and the colored layer 134 are attached to the insulating layer 194 with an adhesive layer 142.

  In the display device 300B, the transistor 40 that drives the liquid crystal element 180 and the transistor 80 that drives the light-emitting element 170 are formed over different surfaces, and thus a structure and a material suitable for driving each display element are used. It is easy to form.

(Embodiment 4)
In this embodiment, a more specific structure example of the display device described in Embodiment 3 will be described with reference to FIGS.

  FIG. 7A is a block diagram of the display device 400. The display device 400 includes a display unit 362, a circuit GD, and a circuit SD. The display portion 362 includes a plurality of pixels 410 arranged in a matrix.

  The display device 400 includes a plurality of wirings G1, a plurality of wirings G2, a plurality of wirings ANO, a plurality of wirings CSCOM, a plurality of wirings S1, and a plurality of wirings S2. The plurality of wirings G1, the plurality of wirings G2, the plurality of wirings ANO, and the plurality of wirings CSCOM are electrically connected to the plurality of pixels 410 and the circuit GD arranged in the direction indicated by the arrow R, respectively. The plurality of wirings S1 and the plurality of wirings S2 are electrically connected to the plurality of pixels 410 and the circuit SD arranged in the direction indicated by the arrow C, respectively.

  Note that, here, for the sake of simplicity, a configuration including one circuit GD and one circuit SD is shown; however, the circuit GD and the circuit SD that drive the liquid crystal element and the circuit GD and the circuit SD that drive the light emitting element are separately provided. May be provided.

  The pixel 410 includes a reflective liquid crystal element and a light-emitting element.

  7B1 and 7B4 illustrate structural examples of the electrode 311 included in the pixel 410. FIG. The electrode 311 functions as a reflective electrode of the liquid crystal element. An opening 451 is provided in the electrode 311 in FIGS. 7B1 and 7B2.

  In FIG. 7B1 and FIG. 7B2, the light-emitting element 360 located in a region overlapping with the electrode 311 is indicated by a broken line. The light emitting element 360 is disposed so as to overlap with the opening 451 included in the electrode 311. Thereby, the light emitted from the light emitting element 360 is emitted to the display surface side through the opening 451.

  In FIG. 7B1, the pixels 410 adjacent in the direction indicated by the arrow R are pixels corresponding to different colors. At this time, as shown in FIG. 7B1, in two pixels adjacent in the direction indicated by the arrow R, it is preferable that the openings 451 are provided at different positions so as not to be arranged in a line. Accordingly, the two light-emitting elements 360 can be separated from each other, and a phenomenon (also referred to as crosstalk) in which light emitted from the light-emitting elements 360 enters the colored layer of the adjacent pixel 410 can be suppressed. In addition, since the two adjacent light emitting elements 360 can be arranged apart from each other, a display device with high definition can be realized even when the EL layer of the light emitting element 360 is separately formed using a shadow mask or the like.

  In FIG. 7B2, the pixels 410 adjacent in the direction indicated by the arrow C are pixels corresponding to different colors. Similarly in FIG. 7B2, similarly, in two pixels adjacent in the direction indicated by the arrow C, it is preferable that the openings 451 are provided at different positions of the electrode 311 so that they are not arranged in a line.

  The smaller the value of the ratio of the total area of the openings 451 to the total area of the non-openings, the brighter the display using the liquid crystal element. In addition, as the value of the ratio of the total area of the openings 451 to the total area of the non-openings is larger, the display using the light emitting element 360 can be brightened.

  The shape of the opening 451 can be, for example, a polygon, a rectangle, an ellipse, a circle, a cross, or the like. Moreover, it is good also as an elongated streak shape, a slit shape, and a checkered shape. Further, the opening 451 may be arranged close to adjacent pixels. Preferably, the opening 451 is arranged close to other pixels displaying the same color. Thereby, crosstalk can be suppressed.

  In addition, as illustrated in FIGS. 7B3 and 7B4, the light-emitting region of the light-emitting element 360 may be located in a portion where the electrode 311 is not provided. Thereby, the light emitted from the light emitting element 360 is emitted to the display surface side.

  In FIG. 7B3, the light emitting elements 360 are not arranged in a line in the two pixels 410 adjacent to each other in the direction indicated by the arrow R. In FIG. 7B4, the light emitting elements 360 are arranged in a line in two pixels adjacent to each other in the direction indicated by the arrow R.

  7B3 can separate the light-emitting elements 360 included in the two adjacent pixels 410, so that crosstalk can be suppressed and higher definition can be achieved as described above. 7B4, since the electrode 311 is not positioned on the side parallel to the arrow C of the light-emitting element 360, light from the light-emitting element 360 can be prevented from being blocked by the electrode 311 and a high viewing angle can be obtained. The characteristics can be realized.

  Various sequential circuits such as a shift register can be used for the circuit GD. A transistor, a capacitor, or the like can be used for the circuit GD. A transistor included in the circuit GD can be formed in the same process as the transistor included in the pixel 410.

  The circuit SD is electrically connected to the wiring S1. For the circuit SD, for example, an integrated circuit can be used. Specifically, an integrated circuit formed on a silicon substrate can be used for the circuit SD.

  For example, the circuit SD can be mounted on a pad electrically connected to the pixel 410 by using a COG method, a COF method, or the like. Specifically, an integrated circuit can be mounted on the pad using an anisotropic conductive film.

  FIG. 8 is an example of a circuit diagram of the pixel 410. In FIG. 8, two adjacent pixels 410 are shown.

  The pixel 410 includes a switch SW1, a capacitor C1, a liquid crystal element 340, a switch SW2, a transistor M, a capacitor C2, a light emitting element 360, and the like. In addition, a wiring G1, a wiring G2, a wiring ANO, a wiring CSCOM, a wiring S1, and a wiring S2 are electrically connected to the pixel 410. In FIG. 8, a wiring VCOM1 electrically connected to the liquid crystal element 340 and a wiring VCOM2 electrically connected to the light emitting element 360 are illustrated.

  FIG. 8 shows an example in which transistors are used for the switch SW1 and the switch SW2.

  The gate of the switch SW1 is connected to the wiring G1. One of the source and the drain of the switch SW1 is connected to the wiring S1, and the other is connected to one electrode of the capacitor C1 and one electrode of the liquid crystal element 340. The other electrode of the capacitive element C1 is connected to the wiring CSCOM. The other electrode of the liquid crystal element 340 is connected to the wiring VCOM1.

  The gate of the switch SW2 is connected to the wiring G2. One of the source and the drain of the switch SW2 is connected to the wiring S2, and the other is connected to one electrode of the capacitor C2 and the gate of the transistor M. The other electrode of the capacitor C2 is connected to one of the source and the drain of the transistor M and the wiring ANO. The other of the source and the drain of the transistor M is connected to one electrode of the light emitting element 360. The other electrode of the light emitting element 360 is connected to the wiring VCOM2.

  FIG. 8 shows an example in which the transistor M has two gates sandwiching a semiconductor and these are connected. As a result, the current that can be passed by the transistor M can be increased.

  A signal for controlling the switch SW1 to be in a conductive state or a non-conductive state can be supplied to the wiring G1. A predetermined potential can be applied to the wiring VCOM1. A signal for controlling the alignment state of the liquid crystal included in the liquid crystal element 340 can be supplied to the wiring S1. A predetermined potential can be applied to the wiring CSCOM.

  A signal for controlling the switch SW2 to be in a conductive state or a non-conductive state can be supplied to the wiring G2. The wiring VCOM2 and the wiring ANO can each be supplied with a potential at which a potential difference generated by the light emitting element 360 emits light. A signal for controlling the conduction state of the transistor M can be supplied to the wiring S2.

  For example, in the case of performing reflection mode display, the pixel 410 illustrated in FIG. 8 is driven by a signal supplied to the wiring G1 and the wiring S1, and can display using optical modulation by the liquid crystal element 340. In the case where display is performed in the transmissive mode, display can be performed by driving the light-emitting element 360 by driving with signals supplied to the wiring G2 and the wiring S2. In the case of driving in both modes, the driving can be performed by signals given to the wiring G1, the wiring G2, the wiring S1, and the wiring S2.

  Note that although FIG. 8 illustrates an example in which one pixel 410 includes one liquid crystal element 340 and one light emitting element 360, the invention is not limited thereto. FIG. 9A illustrates an example in which one pixel 410 includes one liquid crystal element 340 and four light-emitting elements 360 (light-emitting elements 360r, 360g, 360b, and 360w). Unlike the pixel 410 in FIG. 8, the pixel 410 illustrated in FIG. 9A can perform full-color display using a light-emitting element.

  In FIG. 9A, in addition to the example of FIG. 8, a wiring G3 and a wiring S3 are connected to the pixel 410.

  In the example illustrated in FIG. 9A, for example, light emitting elements exhibiting red (R), green (G), blue (B), and white (W) can be used for the four light emitting elements 360, respectively. As the liquid crystal element 340, a reflective liquid crystal element exhibiting white can be used. Thereby, when displaying in reflection mode, white display with high reflectance can be performed. In addition, when display is performed in the transmissive mode, display with high color rendering properties can be performed with low power.

  FIG. 9B illustrates a configuration example of the pixel 410 corresponding to FIG. The pixel 410 includes a light-emitting element 360 w that overlaps with an opening included in the electrode 311, and a light-emitting element 360 r, a light-emitting element 360 g, and a light-emitting element 360 b that are disposed around the electrode 311. The light emitting element 360r, the light emitting element 360g, and the light emitting element 360b preferably have substantially the same light emitting area.

  This embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 5)
In this embodiment, a structure of an input / output panel that can be used as the input / output device of one embodiment of the present invention is described with reference to FIGS.

  FIG. 10 illustrates a structure of the input / output panel of one embodiment of the present invention. FIG. 10 is a cross-sectional view of a pixel included in the input / output panel.

  FIG. 11 illustrates a structure of the input / output panel of one embodiment of the present invention. 11A is a cross-sectional view illustrating the structure of the functional film of the input / output panel shown in FIG. 10, FIG. 11B is a cross-sectional view illustrating the structure of the input unit, and FIG. FIG. 11D is a cross-sectional view illustrating the configuration of the second unit, and FIG. 11D is a cross-sectional view illustrating the configuration of the first unit.

  In the present specification, a variable having an integer value of 1 or more may be used for the sign. For example, (p) including a variable p that takes an integer value of 1 or more may be used as a part of a code that identifies any of the maximum p components. Further, for example, a variable m that takes an integer value of 1 or more and (m, n) including a variable n may be used as part of a code that identifies any one of the maximum m × n components.

  The input / output panel 700TP3 described in this configuration example includes a pixel 702 (i, j) (see FIG. 10). The input / output panel 700TP3 includes the first unit 10, the second unit 20, the input unit 30, and a functional film 770P (see FIG. 11). The first unit 10 includes a functional layer 620, and the second unit 20 includes a functional layer 720.

<Pixel 702 (i, j)>
The pixel 702 (i, j) includes a part of the functional layer 620, a first display element 750 (i, j), and a second display element 650 (i, j) (see FIG. 10). .

  The functional layer 620 includes a first conductive film, a second conductive film, an insulating film 601C, and a pixel circuit 630 (i, j). Note that the pixel circuit 630 (i, j) (not shown) includes, for example, a transistor M. The functional layer 620 includes an optical element 660, a coating film 665, and a lens 680. The functional layer 620 includes an insulating film 628 and an insulating film 621. A material in which the insulating films 621A and 621B are stacked can be used for the insulating film 621.

  For example, a material having a refractive index of 1.55 can be used for the insulating film 621A or the insulating film 621B. Alternatively, a material with a refractive index of 1.6 can be used for the insulating film 621A or the insulating film 621B. Alternatively, acrylic resin or polyimide can be used for the insulating film 621A or the insulating film 621B.

  The insulating film 601C includes a region sandwiched between the first conductive film and the second conductive film, and the insulating film 601C includes an opening 691A.

  The first conductive film is electrically connected to the first display element 750 (i, j). Specifically, it is electrically connected to the electrode 751 (i, j) of the first display element 750 (i, j). Note that the electrode 751 (i, j) can be used for the first conductive film.

  The second conductive film includes a region overlapping with the first conductive film. The second conductive film is electrically connected to the first conductive film in the opening 691A. For example, the conductive film 612B can be used for the second conductive film. The second conductive film is electrically connected to the pixel circuit 630 (i, j). For example, a conductive film functioning as a source electrode or a drain electrode of a transistor used for the switch SW1 of the pixel circuit 630 (i, j) can be used for the second conductive film. By the way, the first conductive film electrically connected to the second conductive film in the opening 691A provided in the insulating film 601C can be referred to as a through electrode.

  The second display element 650 (i, j) is electrically connected to the pixel circuit 630 (i, j). The second display element 650 (i, j) has a function of emitting light toward the functional layer 620. Further, the second display element 650 (i, j) has a function of emitting light toward the lens 680 or the optical element 660, for example.

  In order to be able to visually recognize the display using the second display element 650 (i, j) in a part of the range where the display using the first display element 750 (i, j) can be visually recognized, A display element 650 (i, j) is provided. For example, a shape including a region 751H that does not block light emitted from the second display element 650 (i, j) is used for the electrode 751 (i, j) of the first display element 750 (i, j). The direction in which the external light is incident and reflected on the first display element 750 (i, j) that displays the image information by controlling the intensity of reflecting the external light is shown in the drawing by using a broken arrow. In addition, the direction in which the second display element 650 (i, j) emits light in a part of the range where the first display element 750 (i, j) can be visually recognized is shown in the drawing using solid arrows. .

  Thereby, the display using the 2nd display element can be visually recognized in a part of field which can visually recognize the display using the 1st display element. Alternatively, the user can visually recognize the display without changing the posture of the input / output panel. Alternatively, the object color expressed by the light reflected by the first display element can be multiplied by the light source color expressed by the light emitted by the second display element. Alternatively, a pictorial display can be performed using the object color and the light source color. As a result, a novel input / output panel that is highly convenient or reliable can be provided.

  For example, the first display element 750 (i, j) includes an electrode 751 (i, j), an electrode 752, and a layer 753 containing a liquid crystal material. In addition, an alignment film AF1 and an alignment film AF2 are provided. Specifically, a reflective liquid crystal element can be used for the first display element 750 (i, j).

  For example, a transparent conductive film having a refractive index of 2.0 can be used for the electrode 752 or the electrode 751 (i, j). Specifically, an oxide containing indium, tin, and silicon can be used for the electrode 752 or the electrode 751 (i, j). Alternatively, a material having a refractive index of 1.6 can be used for the alignment film.

  For example, the second display element 650 (i, j) includes an electrode 651 (i, j), an electrode 652, and a layer 653 (j) containing a light-emitting material. The electrode 652 includes a region overlapping with the electrode 651 (i, j). The layer 653 (j) containing a light-emitting material includes a region sandwiched between the electrode 651 (i, j) and the electrode 652. The electrode 651 (i, j) is electrically connected to the pixel circuit 630 (i, j) at the connection portion 622. Specifically, an organic EL element can be used for the second display element 650 (i, j).

  For example, a transparent conductive film having a refractive index of 2.0 can be used for the electrode 651 (i, j). Specifically, an oxide containing indium, tin, and silicon can be used for the electrode 651 (i, j). Alternatively, a material having a refractive index of 1.8 can be used for the layer 653 (j) containing a light-emitting material.

  The optical element 660 has translucency, and the optical element 660 includes a first region, a second region, and a third region.

  The first region includes a region to which visible light is supplied from the second display element 650 (i, j), the second region includes a region in contact with the coating film 665, and the third region is visible light. A function to inject a part is provided. The third region has an area equal to or smaller than the area of the first region to which visible light is supplied.

  The coating film 665 has reflectivity with respect to visible light, and the coating film 665 has a function of reflecting a part of visible light and supplying it to the third region.

  For example, a metal can be used for the coating film 665. Specifically, a material containing silver can be used for the coating film 665. For example, a material containing silver, palladium, or the like, or a material containing silver, copper, or the like can be used for the coating film 665.

<Lens 680>
A material that transmits visible light can be used for the lens 680. Alternatively, a material having a refractive index of 1.3 to 2.5 can be used for the lens 680. For example, an inorganic material or an organic material can be used for the lens 680.

  For example, a material containing an oxide or sulfide can be used for the lens 680.

  Specifically, cerium oxide, hafnium oxide, lanthanum oxide, magnesium oxide, niobium oxide, tantalum oxide, titanium oxide, yttrium oxide, zinc oxide, oxide containing indium and tin, oxide containing indium, gallium, and zinc, etc. Can be used for the lens 680. Alternatively, zinc sulfide or the like can be used for the lens 680.

  For example, a material including a resin can be used for the lens 680. Specifically, a resin in which chlorine, bromine, or iodine is introduced, a resin in which heavy metal atoms are introduced, a resin in which an aromatic ring is introduced, a resin in which sulfur is introduced, or the like can be used for the lens 680. Alternatively, a resin including nanoparticles of a material having a higher refractive index than that of the resin can be used for the lens 680. Titanium oxide or zirconium oxide can be used for the nanoparticles.

<Functional layer 720>
The functional layer 720 includes a region sandwiched between the substrate 770 and the insulating film 601C. The functional layer 720 includes an insulating film 771 and a colored film CF1.

  The colored film CF1 includes a region sandwiched between the substrate 770 and the first display element 750 (i, j).

  The insulating film 771 includes a region sandwiched between the coloring film CF1 and the layer 753 containing a liquid crystal material. Thereby, the unevenness | corrugation based on the thickness of colored film CF1 can be made flat. Alternatively, diffusion of impurities from the coloring film CF1 or the like to the layer 753 containing a liquid crystal material can be suppressed.

  For example, an acrylic resin with a refractive index of 1.55 can be used for the insulating film 771.

<Substrate 670, Substrate 770>
The input / output panel described in this embodiment includes a substrate 670 and a substrate 770.

  The substrate 770 includes a region overlapping with the substrate 670. The substrate 770 includes a region that sandwiches the functional layer 620 with the substrate 670.

  The substrate 770 includes a region overlapping with the first display element 750 (i, j). For example, a material in which birefringence is suppressed can be used for the region.

  For example, a resin material having a refractive index of 1.5 can be used for the substrate 770.

<Junction layer 605>
In addition, the input / output panel described in this embodiment includes a bonding layer 605.

  The bonding layer 605 includes a region sandwiched between the functional layer 620 and the substrate 670 and has a function of bonding the functional layer 620 and the substrate 670 together.

<Structure KB1, Structure KB2>
The input / output panel described in this embodiment includes a structure KB1 and a structure KB2.

  The structure KB1 has a function of providing a predetermined gap between the functional layer 620 and the substrate 770. The structure KB1 includes a region overlapping with the region 751H, and the structure KB1 has a light-transmitting property. Thereby, the light emitted by the second display element 650 (i, j) can be supplied to one surface and emitted from the other surface.

  In addition, the structure KB1 includes a region overlapping with the optical element 660. For example, a material selected so that the difference from the refractive index of the material used for the optical element 660 is 0.2 or less is used for the structure KB1. Thereby, the light which a 2nd display element inject | emits can be utilized efficiently. Alternatively, the area of the second display element can be increased. Or the density of the electric current sent through an organic EL element can be lowered | hung.

  The structure KB2 has a function of controlling the thickness of the polarizing layer 770PB to a predetermined thickness. The structure KB2 includes a region overlapping with the second display element 650 (i, j), and the structure KB2 has a light-transmitting property.

  Alternatively, a material that transmits light of a predetermined color can be used for the structure KB1 or the structure KB2. Thereby, the structure KB1 or the structure KB2 can be used for a color filter, for example. For example, a material that transmits blue, green, or red light can be used for the structure KB1 or the structure KB2. A material that transmits yellow light, white light, or the like can be used for the structure KB1 or the structure KB2.

  Specifically, polyester, polyolefin, polyamide, polyimide, polycarbonate, polysiloxane, acrylic resin, or the like, or a composite material of a plurality of resins selected from these can be used for the structure KB1 or the structure KB2. Alternatively, a material having photosensitivity may be used.

  For example, an acrylic resin having a refractive index of 1.5 can be used for the structure KB1. An acrylic resin with a refractive index of 1.55 can be used for the structure KB2.

<Input unit 30>
The input unit 30 includes a detection element. The detection element has a function of detecting an element close to a region overlapping with the pixel 702 (i, j). Accordingly, position information can be input using a finger or the like that is brought close to the display unit as a pointer.

  For example, a capacitive proximity sensor, an electromagnetic induction proximity sensor, an optical proximity sensor, a resistive proximity sensor, or a surface acoustic wave proximity sensor can be used for the input unit 30. Specifically, a proximity sensor of a surface type capacitance method, a projection type capacitance method, or an infrared detection type can be used.

  For example, a touch sensor having a refractive index of 1.6 including a capacitive proximity sensor can be used for the input unit 30.

<Functional film 770D, functional film 770P, etc.>
The input / output panel 700TP3 described in this embodiment includes a functional film 770D and a functional film 770P.

  The functional film 770D includes a region overlapping with the first display element 750 (i, j). The functional film 770D includes a region sandwiching the first display element 750 (i, j) between the functional layer 620 and the functional film 770D.

  For example, a light diffusion film can be used for the functional film 770D. Specifically, a material having a columnar structure including an axis along a direction intersecting the surface of the base material can be used for the functional film 770D. Thereby, light can be easily transmitted in a direction along the axis and can be easily scattered in other directions. Alternatively, for example, light reflected by the first display element 750 (i, j) can be diffused.

  The functional film 770P includes the polarizing layer 770PB, the retardation film 770PA, or the structure KB2. The polarizing layer 770PB includes an opening, and the retardation film 770PA includes a region overlapping with the polarizing layer 770PB. The structure KB2 is provided in the opening.

  For example, a dichroic dye, a liquid crystal material, and a resin can be used for the polarizing layer 770PB. The polarizing layer 770PB has polarizing properties. Accordingly, the functional film 770P can be used for the polarizing plate.

  The polarizing layer 770PB includes a region overlapping with the first display element 750 (i, j), and the structure KB2 includes a region overlapping with the second display element 650 (i, j). Accordingly, the liquid crystal element can be used for the first display element. For example, a reflective liquid crystal element can be used for the first display element. Alternatively, light emitted from the second display element can be extracted efficiently. Or the density of the electric current sent through an organic EL element can be lowered | hung. Or the reliability of an organic EL element can be improved.

  For example, an antireflection film, a polarizing film, or a retardation film can be used for the functional film 770P. Specifically, a film containing a dichroic dye and a retardation film can be used for the functional film 770P.

  In addition, an antistatic film that suppresses adhesion of dust, a water-repellent film that makes it difficult to adhere dirt, a hard coat film that suppresses generation of scratches due to use, and the like can be used for the functional film 770P.

  For example, a material having a refractive index of 1.6 can be used for the diffusion film. A material having a refractive index of 1.6 can be used for the retardation film 770PA.

  Note that this embodiment can be combined with any of the other embodiments described in this specification as appropriate.

(Embodiment 6)
In this embodiment, an electronic device of one embodiment of the present invention will be described.

<Electronic device 130>
FIG. 12A illustrates an electronic device of one embodiment of the present invention. An electronic device 130 illustrated in FIG. 12A includes a control circuit 144, a storage battery 145, a display portion 102, and a display portion 104. The control circuit 144 preferably has a power management IC.

  The electronic device 130 preferably includes a control circuit 147, a drive circuit 153, and a terminal 146. The drive circuit 153 includes, for example, a driver IC. The drive circuit 153 preferably includes a source driver. The control circuit 147 preferably has an application processor. For example, a terminal compatible with USB (Universal Serial Bus) or a terminal included in the USB is connected to the terminal 146.

  The electronic device 130 preferably has an input unit 148. The input unit 148 is electrically connected to the control circuit 147, for example. The input unit 148 will be described later.

  The electronic device 130 has a gate driver 152. Alternatively, the gate driver 152 may be included in the drive circuit 153.

  The electronic device 130 preferably includes the touch sensor 114. The display unit 102, the display unit 104, and the touch sensor 114 are preferably arranged so as to overlap each other. Here, in this specification and the like, the touch sensor may refer to, for example, a proximity sensor.

  The control circuit 144 is electrically connected to the drive circuit 153. The drive circuit 153 is electrically connected to the display unit 102 and the display unit 104.

  The control circuit 144 is electrically connected to the storage battery 145. The control circuit 144 is electrically connected to the control circuit 147. The control circuit 144 preferably gives a signal to the control circuit 147 via an I2C interface. In the electronic device 130 illustrated in FIG. 12A, two terminals (eg, a positive electrode and a negative electrode) of the first storage battery 145 are electrically connected to the control circuit 144. The control circuit 147 preferably gives a signal to the drive circuit 153 via the MIPI interface.

  For example, the wiring connected to the terminal 146 electrically connects the external power supply and the control circuit 144. FIG. 12 shows an example in which one end of the external power supply 143 is connected to the terminal 146. The other end of the external power supply 143 is connected to, for example, an external power supply. The storage battery 145 is charged from an external power source via the control circuit 144. Further, power may be supplied to the control circuit 144 from an external power source by non-contact power feeding (for example, wireless power feeding using an antenna).

  The control circuit 144 has a function of measuring the capacity of the first storage battery 145. More specifically, for example, the control circuit 144 measures the amount of charge flowing through the storage battery when the first storage battery 145 is charged and discharged, and integrates the amount of charge, thereby increasing the capacity of the first storage battery 145. measure.

  For example, a coulomb counter can be used for measuring the charge amount. In the coulomb counter, for example, the charge amount is measured using an integration circuit.

  The control circuit 147 is given the capacity value of the first storage battery 145 from the control circuit 147. The control circuit 147 determines the display mode of the electronic device 130 according to the capacity value of the first storage battery 145.

  When charging is performed, the current or voltage of the first storage battery 145 is controlled by a charging circuit connected to the first storage battery 145. For example, a transistor can be used to control the current value during constant current charging and the voltage value during constant voltage charging. By controlling the gate voltage in the transistor, switching between a constant current and a constant voltage can be performed.

  The electronic device 130 preferably has a protection circuit. The protection circuit preferably has a function of protecting the first storage battery 145 from overcharge, overdischarge, overcurrent, and the like.

  In the control circuit 147, for example, a start pulse (GSP), a clock signal (GCLK), and the like are generated as a gate driver control signal, and a start pulse (SSP), a clock signal (SCLK), and the like are generated as a source driver control signal. Is done. In some cases, these control signals are not a single signal but a signal group.

  In addition, the control circuit 147 may have a function of controlling supply of the power supply voltage from the control circuit 144 to the gate driver and the source driver, and stop thereof.

  For example, in the gate driver, when GSP is input, a gate signal is generated according to GCLK and sequentially output to each gate line. The gate signal is a signal for selecting a pixel to which a data signal is written.

  For example, the source driver has a function of processing an image signal (Video signal), generating a data signal, and outputting the data signal to a source line. When SSP is input to the source line, a data signal is generated in accordance with SCLK and sequentially output to each source line.

  The display unit 102 includes a plurality of pixels 61. The display unit 104 includes a plurality of pixels 62.

  The display portion 102 includes a display element 101 (the display element 101 is illustrated in FIG. 12B described later). The display element 101 preferably includes a liquid crystal element. In addition, the display element 101 preferably has a function of displaying gradation using reflection of light. For example, a reflective liquid crystal element can be used as the display element 101. The liquid crystal element has a capacitor structure that accumulates charges. The liquid crystal element has two electrodes (a pixel electrode and a common electrode) and a liquid crystal sandwiched between them.

  The reflective liquid crystal element is displayed using external light as a light source. An electronic device using a reflective liquid crystal element can obtain a clear and beautiful image. In addition, since no backlight is required, power consumption can be reduced. In addition, response speed is faster than electronic paper. Here, in an electronic device using a reflective liquid crystal element, power consumption of the display device can be extremely reduced by using an idling stop (IDS) drive described later. A display device combining a reflective liquid crystal element and IDS driving is a portable terminal that displays books, particularly books including figures and images, such as textbooks and reference books, because of its low power consumption and beautiful display image quality. Are better.

  The display portion 104 includes a display element 103 (the display element 103 is illustrated in FIG. 12B described later). The display element 103 is preferably a light emitting display element. For example, an organic EL element can be used as the display element 103. Alternatively, a transmissive liquid crystal element can be used as the display element 103. The transmissive liquid crystal element includes, for example, a backlight and a switching element that controls a voltage applied to the liquid crystal. A transistor may be used as the switching element. In the case where a reflective liquid crystal element is used as the display element 101 and a transmissive liquid crystal element is used as the display element 103, the display element 101 and the display element 103 may use the same layer of liquid crystal. You may provide a liquid crystal layer separately, for example, laminating | stacking. When the electronic device 130 includes the display element 103, a high-quality image can be displayed even when the outside light is dark. That is, the electronic device 130 can be used in a wide variety of scenes and environments. In addition, it is preferable to display the display element 101 and the display element 103 in combination because image expressibility is improved.

  Each of the display portion 102 and the display portion 104 includes a plurality of pixels. The pixel has a switching element whose connection with a source line (for example, the wiring GL and the wiring GE in the following FIG. 12B) is controlled by a gate signal (for example, the transistor 63 and the transistor 66 in FIG. 12B). Have When the switching element is turned on, a data signal is written from the source line (for example, the wiring SL and the wiring DL in FIG. 12B) to the pixel. When the switching element is turned off, the pixel is in a data holding state.

  As an example of a pixel included in the display portion 102, a pixel 61 is illustrated in FIG. The pixel 61 includes a display element 101 and a transistor 63. The gate of the transistor 63 is electrically connected to a wiring GL to which a gate signal is supplied. One of a source and a drain of the transistor 63 is electrically connected to a wiring SL to which a data signal is supplied, and the other is electrically connected to one electrode of the display element 101. An OS-FET is preferably used for the transistor 63.

  As an example of a pixel included in the display portion 104, a pixel 62 is illustrated in FIG. The pixel 62 includes a display element 103. The pixel 62 preferably includes a transistor 65, a transistor 66, and the like.

  It is preferable that the pixel 61 and the pixel 62 are arranged adjacent to each other. Further, the pixel 61 and the pixel 62 may partially overlap each other.

  When the same image is displayed on the display unit 102 and the display unit 104, for example, the same image signal is displayed on the pixel 61 and the pixel 62. By displaying the same image on the display unit 102 and the display unit 104, for example, an image having a unique texture can be obtained. In addition, an eye-friendly image may be obtained.

  The electronic device 130 has three display modes: a Hybrid mode, an R-display mode, and an E-display mode. In the Hybrid mode, the display unit 102 and the display unit 104 are displayed. In the R-display mode, the display unit 102 is displayed. In the E-display mode, the display unit 104 is displayed. The display mode can be switched according to, for example, the intensity of external light, user preference, image type, and the like. Alternatively, as will be described later, the mode is switched according to the remaining capacity of the storage battery.

  The display unit 102 and the display unit 104 of the electronic device 130 may display images and characters indicating which display mode is selected in the electronic device 130.

  For example, the electronic device 130 is set to the R-display mode when the external light is strong, and is set to the E-display mode or the Hybrid mode when the external light is weak. By using the Hybrid mode, an image having a unique texture can be obtained. In addition, an eye-friendly image may be obtained. In the R-display mode, the display function of the display unit 104 is stopped.

  By adopting the R-display mode, power consumption can be suppressed because a backlight is unnecessary. In addition, when a reflective liquid crystal element is used as the display element 101 included in the display portion 102 and IDS driving is used as an operation method, power consumption can be extremely reduced. When the remaining amount of the first storage battery 145 included in the electronic device 130 is small, it is preferable to use the R-display mode with lower power consumption because the usage time of the electronic device 130 can be extended.

  Further, by displaying the display unit 104, that is, in the E-display mode or the Hybrid mode, for example, a display with a wider viewing angle may be obtained. By obtaining a display with a wide viewing angle, for example, the electronic device 130 can be used regardless of the viewing angle. In some cases, a plurality of people can easily view the same display screen. In the E-display mode, the display function of the display unit 102 is stopped.

  Further, for example, a color image may be displayed on the display unit 102, or a gray image may be displayed. It is preferable that a color image is displayed on the display unit 104.

  Consider a case where a gray image is displayed on the display unit 102 and a color image is displayed on the display unit 104 in the electronic device 130. In this case, for example, the display unit 102 is displayed when the image displayed on the electronic device 130 is a gray image, and the display unit 104 is displayed when the image is a color image. Further, for example, character information composed of a gray image or a black and white image may be displayed on the display unit 102, and a color image composed of a figure and a photograph may be displayed on the display unit 104.

  The input unit 138 is, for example, an electrical switch (contact) provided in the electronic device 130 or a mechanical switch. The input unit 138 may have a convex part, for example, a button-like shape. For example, an operation button, an operation key, a switch, or the like included in the electronic device described in an embodiment to be described later can be used.

  Alternatively, the input unit 138 may be the touch sensor 114, for example. For example, a signal can be input by touching the touch sensor 114 in a region overlapping with an input portion displayed on the display portion 102 and the display portion 104.

<Operation example 1>
The operation of the display device of one embodiment of the present invention is described with reference to a flow shown in FIG.

  First, in step S001, the external power supply 143 and the like are connected to the terminal 146. The external power supply 143 preferably has a terminal corresponding to USB. By connecting an external power supply to the external power supply 143, the first storage battery 145 can be charged. Alternatively, a connector corresponding to USB may be connected to the terminal 146 in step S001.

  Next, in step S <b> 101, it is determined whether power is supplied from the external power supply 143 to the terminal 146. If the power is supplied, the process proceeds to step S102, and if not, the process proceeds to step S103.

  When the process proceeds to step S102, the display mode of the electronic device 130 is not limited. After step S102, the process returns to step S101.

  For example, the control circuit 147 determines the display mode based on the remaining amount of the first storage battery 145 given from the control circuit 144. Based on the determined display mode, a signal is given to the drive circuit 153 from the control circuit 147. When the remaining amount of the first storage battery 145 becomes almost zero, the control circuit 147 switches the supply destination to the second storage battery 140 and restricts the function of the electronic device 130 to the emergency call mode.

  In step S103, if the remaining amount of the first storage battery 145 is less than or equal to the first threshold power P1, the process proceeds to step S104, and if greater than P1, the process proceeds to step S105.

  P1 may be provided with an initial set value in advance, or a user who uses the electronic device may set the first threshold power P1.

  When the process proceeds to step S105, the display mode of the electronic device 130 is not restricted. After step S105, the process returns to step S103.

  When the process proceeds to step S104, the display mode of the electronic device 130 is limited to the R-display mode. After step S104, the process proceeds to step S106.

  Here, in step S104, an alert may be displayed to indicate to the user that the display mode of the electronic device 130 is limited to the R-display mode. For example, an alarm sound or a vibration operation may be generated in the electronic device 130. Alternatively, for example, a message may be displayed on the display unit 102 of the electronic device 130. Alternatively, an image or a character indicating that the display device 102 of the electronic device 130 is limited to the R-display mode may be displayed.

After step S104, the process proceeds to step S301. In step S301, when the remaining amount of the first storage battery 145 is larger than P2, the process does not proceed to the next step until the remaining amount of the first storage battery 145 becomes equal to or less than the second threshold power P2. If P2 or less, the process proceeds to step S302.

  The second threshold power P2 is larger than the third threshold power P3. The operation example shown in FIG. 13 shows an example in which P2 is equal to or less than P1. When P2 is larger than P1, step S301 and step S302 may be performed after step S101 and step S105 and before step S103.

  In step S302, the operation of function A is stopped or restricted.

  As an example, consider a case in which an electronic device to which the electronic device 130 is applied has three functions of a telephone call, information communication via the Internet, and imaging by a camera. Imaging with a camera may consume more power than other functions, such as calls. On the other hand, a call is more urgent and has a higher priority than other functions. Therefore, imaging by the camera is selected as function A in step S302. That is, in step S302, the activation of the camera is prohibited or restricted. Alternatively, execution of application software such as a game may be stopped or the speed may be limited.

  Next, when the remaining amount of the first storage battery 145 is larger than P3 in step S106, the process does not proceed to the next step until the remaining amount of the first storage battery 145 becomes equal to or less than P3. If P3 or less, the process proceeds to step S401.

  In step S401, for example, the power supply of the electronic device 130 is switched to the second storage battery 140, and the operation of the electronic device is limited, specifically set so that an emergency contact (call) can be made.

  Here, in step S106, it is determined whether or not the remaining amount is P3 or less. For example, whether or not the first storage battery 145 is equal to or lower than the voltage VL is used as a determination criterion. Here, the voltage VL is, for example, a voltage near the lower limit value of the discharge voltage of the first storage battery 145. By using the voltage VL as a criterion, overdischarge may be more difficult to occur.

  The electronic device 130 is operated by the above flow.

<IDS drive>
Consider a case where an image that does not change with time or has a slow change frequency is displayed on the display unit 102, such as a still image. The OS-FET has extremely low off-leakage. By using an OS-FET for the transistor 63 which is a switching transistor of a pixel of a liquid crystal element, leakage is suppressed to the limit, so that deterioration of data can be suppressed and a data holding time can be extremely increased. For example, it is possible to reduce the refresh frequency when displaying a still image in which image data does not vary for a long period of time or an image having a slow change frequency of image data, and therefore, display can be performed at a low frequency. The power consumption of the electronic device can be reduced by lowering the display frequency.

  For example, when a still image or the like is displayed, the display frequency can be 1 Hz or less, more preferably 0.3 Hz or less, and still more preferably 0.1 Hz or less. In this way, the drive of the display device in the case of performing display with a frequency of 1 Hz or less may be referred to as “IDS drive”. Details of the “IDS drive” will be described later.

  In this manner, by using the excellent characteristics of the OS-FET, it is possible to realize an excellent display with little deterioration in image quality even when the rewriting frequency is low.

  A comparison between the case of performing IDS driving and the case of writing an image signal for each frame will be described with reference to FIG. FIG. 14 is a timing chart showing an example of GVDD, GSP, and GCLK when the electronic device 130 is driven. Here, GVDD is a high power supply voltage of the gate driver 152.

  FIG. 14A shows a timing chart in the case of driving at a relatively fast frequency, for example, 30 Hz to 240 Hz, more preferably 50 Hz to 130 Hz, when writing an image signal for each frame, for example, displaying a moving image. .

  First, in the first frame (Frame 1), with the GSP input as a trigger, the gate driver 152 generates a gate signal according to GCLK and outputs it to the gate line. When an SSP (not shown) is applied to the source driver included in the drive circuit 153, an image signal is processed according to SCLK (not shown) to generate Vdata, and sequentially output to the source line. At this time, the polarity of Vdata is set to be positive.

  Next, in the second frame (Frame 2), a gate signal and Vdata are generated in the same procedure. If the polarity applied to the liquid crystal element is biased, the liquid crystal element may be greatly deteriorated. Therefore, the positive polarity and the negative polarity may be written alternately. In the second frame, the polarity of Vdata is set to be negative. After the third frame (Frame 3), positive polarity and negative polarity are alternately written for each frame.

  FIG. 14B shows a timing chart when the image signal is the same over several frames, for example, when a still image is displayed. The driving method illustrated in FIG. 14B is a driving method in which data rewriting is stopped after data writing processing is performed. This is called “IDS driving”. For example, when displaying a still image, it is not necessary to rewrite data every frame. Therefore, when the still image is displayed, if the display unit 102 is operated using IDS driving, power consumption can be reduced and flickering of the screen can be suppressed. In the writing period, in FIG. 14B, when the first frame (Frame 1) is the period 31 and the second frame (Frame 2) and so on, for example, the same image signal continues, no new writing is performed. The written image may be retained. In FIG. 14B, a period for holding an image is a period 32 from the second frame until the next writing is performed. The period 31 may be referred to as a writing period, and the period 32 may be referred to as a holding period.

  First, in Frame 1, with the GSP input as a trigger, the gate driver 152 generates a gate signal according to GCLK and outputs it to the gate line. When an SSP (not shown) is applied to the source driver included in the drive circuit 153, an image signal is processed according to SCLK (not shown) to generate Vdata, and sequentially output to the source line.

  Next, after Frame 2, the transistor 63, which is a pixel switching transistor, is turned off to hold the written image. In Frame 2 and later, since data rewriting is stopped, supply of GSP and GCLK can be stopped. Further, the supply of GVDD may be stopped. Power consumption can be reduced by stopping the supply of GSP, GCLK, GVDD, and the like.

  Note that although the writing period (period 31) is Frame 1 in FIG. 14B, the writing period may be performed over a plurality of frames. For example, the writing period may be from Frame 1 to Frame 3, and the holding period (period 32) may be Frame 4 or later. Note that since the polarity of the holding period is biased when the writing period spans an even number of frames, the writing period is preferably an odd number of frames.

In order to perform IDS driving, the anisotropy of the dielectric constant of the liquid crystal layer described later is set to 2 or more and 3.8 or less, and the resistivity of the liquid crystal layer is set to 1.0 × 10 ¹⁴ (Ω · cm) or more and 1. It is preferably 0 × 10 ¹⁵ (Ω · cm) or less.

  When the anisotropy of the dielectric constant of the liquid crystal layer is high, the interaction with the electric field is large, and the behavior of the liquid crystal layer is accelerated, so that the display panel can be operated at high speed. Note that if the anisotropy of the dielectric constant of the liquid crystal layer exceeds 3.8, it becomes difficult to purify the impurities in the liquid crystal. When these impurities remain in the liquid crystal layer, the conductivity of the liquid crystal layer increases, and in the case of IDS driving, it is difficult to maintain the voltage written in the pixel.

  On the other hand, when the dielectric constant anisotropy of the liquid crystal layer is low, the amount of impurities in the liquid crystal layer can be reduced, so that the conductivity of the liquid crystal layer can be reduced. If the anisotropy of the dielectric constant of the liquid crystal layer is less than 2, since the interaction with the electric field is small and the behavior of the liquid crystal layer is slow, the drive voltage must be set high to promote high-speed operation. It is difficult to reduce power consumption.

Therefore, the anisotropy of the dielectric constant of the liquid crystal layer is 2 or more and 3.8 or less, and the resistivity of the liquid crystal layer is 1.0 × 10 ¹⁴ (Ω · cm) or more and 1.0 × 10 ¹⁵ (Ω · cm) or less, IDS driving is possible, and power consumption of the display panel can be reduced.

  This embodiment can be implemented in appropriate combination with any of the other embodiments.

(Embodiment 7)
In this embodiment, a portable information terminal 6000 including a display module which is one embodiment of the present invention will be described.

  A portable information terminal 6000 including the display module illustrated in FIG. 15A includes a display panel 6006 connected to an FPC 6005, a frame 6009, a printed board 6010, and a plurality of batteries 6011a between an upper cover 6001 and a lower cover 6002. , 6011b, 6011c, and 6011d.

As shown in Embodiment 1, one of the batteries 6011a, 6011b, 6011c, and 6011d is used as an emergency battery.

  For example, a display device manufactured using one embodiment of the present invention described above can be used for the display panel 6006. Thereby, a portable information terminal can be manufactured with a high yield.

  The shapes and dimensions of the upper cover 6001 and the lower cover 6002 can be changed as appropriate in accordance with the size of the display panel 6006.

  Further, a touch panel may be provided over the display panel 6006. As the touch panel, a resistive film type or capacitive type touch panel can be used by being superimposed on the display panel 6006. Further, without providing a touch panel, the display panel 6006 can have a touch panel function.

  The frame 6009 has a function as an electromagnetic shield for blocking electromagnetic waves generated by the operation of the printed board 6010 in addition to a protective function of the display panel 6006. The frame 6009 may function as a heat sink.

  The printed board 6010 includes a power supply circuit, a signal processing circuit for outputting a video signal and a clock signal. The power source for supplying power to the power supply circuit may be an external commercial power source or a power source by a battery 6011 provided separately. The battery 6011 can be omitted when a commercial power source is used.

  In addition, the portable information terminal 6000 including the display module may be additionally provided with a member such as a polarizing plate, a retardation plate, or a prism sheet.

  FIG. 15B is a schematic cross-sectional view of a portable information terminal 6000 having a display module including an optical touch sensor.

  A portable information terminal 6000 having a display module includes a light emitting unit 6015 and a light receiving unit 6016 provided on a printed board 6010. Further, a region surrounded by the upper cover 6001 and the lower cover 6002 has a pair of light guide portions (light guide portion 6017a and light guide portion 6017b).

  For the upper cover 6001 and the lower cover 6002, for example, plastic can be used. Further, the upper cover 6001 and the lower cover 6002 can each be thin (for example, 0.5 mm to 5 mm). Therefore, the portable information terminal 6000 having the display module can be extremely lightweight. Further, since the upper cover 6001 and the lower cover 6002 can be manufactured with a small amount of material, manufacturing cost can be reduced.

  The display panel 6006 is provided so as to overlap the printed circuit board 6010 and the batteries 6011a, 6011b, 6011c, and 6011d with a frame 6009 interposed therebetween. The batteries 6011a, 6011b, 6011c, and 6011d are thin storage batteries that are laminated and sealed. The display panel 6006 and the frame 6009 are fixed to the light guide unit 6017a and the light guide unit 6017b.

  Light 6018 emitted from the light emitting unit 6015 passes through the upper part of the display panel 6006 by the light guide unit 6017a and reaches the light receiving unit 6016 through the light guide unit 6017b. For example, the touch operation can be detected by blocking the light 6018 by a detection target such as a finger or a stylus.

  For example, a plurality of light emitting units 6015 are provided along two adjacent sides of the display panel 6006. A plurality of light receiving portions 6016 are provided at positions facing the light emitting portion 6015 with the display panel 6006 interposed therebetween. Thereby, the information on the position where the touch operation is performed can be acquired.

  The light emitting unit 6015 can use a light source such as an LED element. In particular, it is preferable to use a light source that emits infrared rays that are not visually recognized by the user and harmless to the user as the light emitting unit 6015.

  The light receiving unit 6016 can be a photoelectric element that receives light emitted from the light emitting unit 6015 and converts the light into an electrical signal. Preferably, a photodiode capable of receiving infrared light can be used.

  As the light guide portion 6017a and the light guide portion 6017b, a member that transmits at least the light 6018 can be used. By using the light guide unit 6017a and the light guide unit 6017b, the light emitting unit 6015 and the light receiving unit 6016 can be arranged below the display panel 6006, and external light reaches the light receiving unit 6016 and the touch sensor malfunctions. Can be suppressed. In particular, it is preferable to use a resin that absorbs visible light and transmits infrared rays. Thereby, malfunction of a touch sensor can be controlled more effectively.

In the present embodiment, a thin storage battery is shown as the storage battery, but various types of storage batteries such as other coin-type, cylindrical and sealed storage batteries, and prismatic storage batteries can be used. Further, a structure in which a plurality of positive electrodes, negative electrodes, and separators are stacked, or a structure in which positive electrodes, negative electrodes, and separators are wound may be employed. For example, examples of other storage batteries are shown in FIGS.

<Example configuration of storage battery>
16 and 17 show a configuration example of a thin storage battery. A wound body 993 illustrated in FIG. 16A includes a negative electrode 994, a positive electrode 995, and a separator 996.

The wound body 993 is obtained by winding the negative electrode 994 and the positive electrode 995 so as to overlap each other with the separator 996 interposed therebetween, and winding the laminated sheet. A rectangular storage battery is manufactured by covering the wound body 993 with a rectangular sealing container or the like.

Note that the number of stacked layers including the negative electrode 994, the positive electrode 995, and the separator 996 may be appropriately designed according to the required capacity and element volume. The negative electrode 994 is connected to a negative electrode current collector (not shown) via one of a lead electrode 997 and a lead electrode 998, and the positive electrode 995 is connected to the positive electrode current collector (not shown) via the other of the lead electrode 997 and the lead electrode 998. Connected).

A storage battery 990 illustrated in FIGS. 16B and 16C includes a wound body 993 described above in a space formed by bonding a film 981 serving as an exterior body and a film 982 having a recess by thermocompression bonding or the like. Is stored. The wound body 993 includes a lead electrode 997 and a lead electrode 998, and is impregnated with an electrolytic solution inside the film 981 and the film 982 having a recess.

For the film 981 and the film 982 having a recess, for example, a metal material such as aluminum or a resin material can be used. When a resin material is used as a material for the film 981 and the film 982 having a recess, the film 981 and the film 982 having a recess can be deformed when an external force is applied, and a flexible storage battery is manufactured. be able to.

16B and 16C show an example in which two films are used, a space is formed by bending one film, and the winding body 993 described above is formed in the space. It may be stored.

Further, a flexible power storage device can be manufactured by using a resin material or the like for an exterior body or a sealing container, instead of a power storage device in which a flexible portion is only a thin storage battery. However, when the exterior body or the sealing container is made of a resin material, the portion to be connected to the outside is made of a conductive material.

For example, an example of another thin storage battery having flexibility is shown in FIG. Since the wound body 993 in FIG. 17A is the same as that shown in FIG. 16A, detailed description thereof will be omitted.

A storage battery 990 illustrated in FIGS. 17B and 17C is obtained by housing the above-described wound body 993 in the exterior body 991. The wound body 993 has a lead electrode 997 and a lead electrode 998, and is impregnated with an electrolytic solution inside the exterior bodies 991, 992. For the exterior bodies 991, 992, for example, a metal material such as aluminum or a resin material can be used. When a resin material is used as the material of the exterior bodies 991 and 992, the exterior bodies 991 and 992 can be deformed when an external force is applied, and a flexible thin storage battery can be manufactured.

By using an electrode including an active material according to one embodiment of the present invention for a flexible thin battery, the active material is cleaved even when stress is applied to the electrode by repeatedly bending the thin battery. Can be prevented.

<Example structure of power storage system>
In addition, structural examples of the power storage system will be described with reference to FIGS. Here, the power storage system refers to, for example, a device equipped with a power storage device.

18A and 18B are external views of a power storage system. The power storage system includes a circuit board 900 and a storage battery 913. A label 910 is attached to the storage battery 913. Further, as illustrated in FIG. 18B, the power storage system includes a terminal 951, a terminal 952, an antenna 914, and an antenna 915.

The circuit board 900 includes a terminal 911 and a circuit 912. The terminal 911 is connected to the terminal 951, the terminal 952, the antenna 914, the antenna 915, and the circuit 912. Note that a plurality of terminals 911 may be further provided, and each of the plurality of terminals 911 may be a control signal input terminal, a power supply terminal, or the like.

The circuit 912 may be provided on the back surface of the circuit board 900. The antenna 914 and the antenna 915 are not limited to a coil shape, and may be a linear shape or a plate shape, for example.

An antenna such as a planar antenna, an aperture antenna, a traveling wave antenna, an EH antenna, a magnetic field antenna, or a dielectric antenna may be used. Alternatively, the antenna 914 or the antenna 915 may be a flat conductor. The flat conductor can function as one of electric field coupling conductors. That is, the antenna 914 or the antenna 915 may function as one of the two conductors of the capacitor. Thereby, not only an electromagnetic field and a magnetic field but power can also be exchanged by an electric field.

The line width of the antenna 914 is preferably larger than the line width of the antenna 915. Accordingly, the amount of power received by the antenna 914 can be increased.

The power storage system includes a layer 916 between the antenna 914 and the antenna 915 and the storage battery 913. The layer 916 has a function of shielding an electromagnetic field generated by the storage battery 913, for example. As the layer 916, for example, a magnetic material can be used.

Note that the structure of the power storage system is not limited to the structure illustrated in FIG.

For example, as shown in FIGS. 19A-1 and 19A-2, an antenna is provided on each of a pair of opposed surfaces of the storage battery 913 shown in FIGS. 18A and 18B. It may be provided. FIG. 19A-1 is an external view seen from one side direction of the pair of surfaces, and FIG. 19A-2 is an external view seen from the other side direction of the pair of surfaces. Note that for the same portion as the power storage system illustrated in FIGS. 18A and 18B, the description of the power storage system illustrated in FIGS. 18A and 18B can be incorporated as appropriate.

As shown in FIG. 19 (A-1), an antenna 914 is provided on one of a pair of surfaces of the storage battery 913 with a layer 916 interposed therebetween, and as shown in FIG. 19 (A-2), a pair of surfaces of the storage battery 913 is provided. An antenna 915 is provided with the layer 917 interposed therebetween. The layer 917 has a function of shielding an electromagnetic field generated by the storage battery 913, for example. As the layer 917, for example, a magnetic material can be used.

With the above structure, the size of both the antenna 914 and the antenna 915 can be increased.

Alternatively, as shown in FIG. 19B-1 and FIG. 19B-2, each of the pair of opposed surfaces of the storage battery 913 shown in FIG. 18A and FIG. An antenna may be provided. FIG. 19B-1 is an external view seen from one side of the pair of surfaces, and FIG. 19B-2 is an external view seen from the other side of the pair of surfaces. Note that for the same portion as the power storage system illustrated in FIGS. 18A and 18B, the description of the power storage system illustrated in FIGS. 18A and 18B can be incorporated as appropriate.

As shown in FIG. 19 (B-1), an antenna 914 and an antenna 915 are provided on one of a pair of surfaces of the storage battery 913 with a layer 916 interposed therebetween, and as shown in FIG. 19 (B-2), the storage battery 913 An antenna 918 is provided with the layer 917 interposed between the other of the pair of surfaces. The antenna 918 has a function of performing data communication with an external device, for example. For the antenna 918, for example, an antenna having a shape applicable to the antenna 914 and the antenna 915 can be used. As a communication method between the power storage system and the other devices via the antenna 918, a response method that can be used between the power storage system and the other devices such as NFC can be applied.

  This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.

(Embodiment 8)
In this embodiment, an example of an electronic device including the display device according to one embodiment of the present invention will be described.

  FIG. 20A illustrates an example of an electronic device including the display device according to one embodiment of the present invention. FIG. 20A illustrates a tablet-type information terminal 6200 which includes a housing 6221, a display device 6222, operation buttons 6223, and a speaker 6224. Further, a function as a position input device may be added to the display device 6222 according to one embodiment of the present invention.

  The function as a position input device can be added by providing a touch panel on the display device. Alternatively, the function as a position input device can be added by providing a photoelectric conversion element called a photosensor in a pixel portion of a display device. Further, the operation button 6223 can include any one of a power switch for starting the information terminal 6200, a button for operating an application of the information terminal 6200, a volume adjustment button, a switch for turning on or off the display device 6222, and the like. In the information terminal 6200 illustrated in FIG. 20A, the number of the operation buttons 6223 is four, but the number and arrangement of the operation buttons included in the information terminal 6200 are not limited thereto.

  Although not illustrated, the information terminal 6200 illustrated in FIG. 20A includes a sensor (force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, Even a configuration having a function of measuring magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, smell, infrared rays, etc.) Good. In particular, by providing a measuring device having a sensor for measuring inclination, such as a gyro sensor and an acceleration sensor, the orientation of the information terminal 6200 shown in FIG. ) Can be automatically switched according to the orientation of the information terminal 6200.

  Further, by combining the information on the tilt with the information on the incident angle and the illuminance of the external light obtained from the optical sensor 6225X and the optical sensor 6225Y, the color of the image data projected on the display device 6222 can be adjusted more accurately. The gradation can be adjusted. In this case, an imaging sensor is provided in the housing 6221 to acquire information on the position of the user's eyes (or the direction of the line of sight) with respect to the information terminal 6200 and combine the information on the tilt, the incident angle of external light, and the illuminance. Thus, the color and gradation of the image displayed on the display device 6222 can be adjusted more accurately.

  Although not illustrated, the information terminal 6200 illustrated in FIG. 20A may include a microphone and a speaker. With this configuration, for example, the information terminal 6200 can be provided with a call function such as a mobile phone. In addition, as illustrated in FIG. 20A, the information terminal 6200 preferably includes a camera 6226. Although not illustrated, the information terminal 6200 illustrated in FIG. 20A may have a structure including a flashlight or a light-emitting device for illumination.

  Although not illustrated, the information terminal 6200 illustrated in FIG. 20A may include a device that acquires biological information such as a fingerprint, a vein, an iris, or a voiceprint. By applying this configuration, an information terminal 6200 having a biometric authentication function can be realized.

  Although not illustrated, the information terminal 6200 illustrated in FIG. 20A may have a microphone. By applying this configuration, the information terminal 6200 can be provided with a call function. In some cases, the information terminal 6200 can be provided with a voice decoding function. By providing the information terminal 6200 with a voice decoding function, the information terminal 6200 can have a function of operating the information terminal 6200 by voice recognition, a function of reading a voice or a conversation and creating a conversation record, and the like. . Thereby, it can utilize, for example as minutes preparations, such as a meeting.

  FIG. 20B illustrates a cellular phone. A display device 5902, a microphone 5907, a speaker 5904, a camera 5903, an external connection portion 5906, and an operation button 5905 according to one embodiment of the present invention are provided in a housing 5901 having a curved surface. Is provided. By using the display device 5902 according to one embodiment of the present invention for a cellular phone, power that can be communicated in an emergency can be secured.

  FIG. 20C illustrates a tablet personal computer including a housing 5301, a housing 5302, a display device 5303 according to one embodiment of the present invention, an optical sensor 5304, an optical sensor 5305, a switch 5306, and the like. The display device 5303 is supported by a housing 5301 and a housing 5302. Since the display device 5303 is formed using a flexible substrate, the display device 5303 has a function of flexibly bending the shape. By changing the angle between the housing 5301 and the housing 5302 at the hinges 5307 and 5308, the display device 5303 can be folded so that the housing 5301 and the housing 5302 overlap with each other. Although not shown, an open / close sensor may be incorporated, and the change in the angle may be used as information on the use condition in the display device 5303. The optical sensor 5304 is attached to the housing 5301, and the optical sensor 5305 is attached to the housing 5302. With the above structure, information on the incident angle of external light to the display device 5303 in the region supported by the housing 5301 and information on the incident angle of external light on the display device 5303 in the region supported by the housing 5302 are displayed. Both of them can be used as information on usage conditions in the display device 5303. By using the display device 5303 according to one embodiment of the present invention for a tablet personal computer, power of mail that can be notified in an emergency can be secured.

  FIG. 21A illustrates a wristwatch-type portable information terminal 5200, which includes the housing 5201, the display device 5202 according to one embodiment of the present invention, the belt 5203, the optical sensor 5204, the switch 5205, and the like. By using the display device 5202 according to one embodiment, power that can be contacted in an emergency can be secured.

  The electronic devices illustrated in FIGS. 20 and 21 may supply power by contactless power feeding (for example, wireless power feeding using an antenna). FIG. 21B illustrates an example in which the portable information terminal 5200 illustrated in FIG. 21A is charged using the power transmission device 5209. FIG. 21C illustrates an example in which the display device 5202 of the portable information terminal 5200 is placed on the power transmission device 5209. Here, although not illustrated, an antenna is preferably provided in the display device 5202 or a region below the display device 5202.

As shown in FIG. 21C, the portable information terminal 5200 can be charged wirelessly using a radio wave 5208 from the power transmission device 5209. By using the display device 5202 according to one embodiment of the present invention for the portable information terminal 5200, power that can be contacted in an emergency can be secured.

  This embodiment can be implemented in appropriate combination with any of the other embodiments.

AF1 Alignment film AF2 Alignment film CF1 Colored film KB1 Structure KB2 Structure SW1 Switch 10 Unit 20 Unit 30 Input unit 31 Period 32 Period 61 Pixel 62 Pixel 63 Transistor 65 Transistor 66 Transistor 101 Display element 102 Display section 104 Display section 114 Touch sensor 130 Electronic Device 140 Second Storage Battery 143 External Power Supply 144 Control Circuit 145 First Storage Battery 146 Terminal 147 Control Circuit 148 Input Unit 152 Gate Driver 153 Drive Circuit 700TP3 Input / Output Panel 720 Functional Layer 751H Region 752 Electrode 753 Layer Containing Liquid Crystal Material 770 Substrate 770D Functional film 770P Functional film 770PA Retardation film 770PB Polarizing layer 771 Insulating film 6000 Portable information terminal 6001 having display module Upper cover 6002 Part cover 6005 FPC
6006 Display panel 6009 Frame 6010 Printed circuit board 6011a Battery 6011b Battery 6011c Battery 6011d Battery 6015 Light emitting part 6016 Light receiving part 6017a Light guiding part 6017b Light guiding part 6018 Light

Claims (9)

A display unit;
Communication means;
A first secondary battery for supplying power to the display unit;
A second secondary battery having a smaller battery capacity than the first secondary battery;
Means for detecting the remaining amount of the first secondary battery;
Means for switching the power supply destination to the display unit to the second secondary battery when the detection means detects that the remaining amount of the first secondary battery is lower than a threshold power,
An electronic device capable of communicating at least once by the communication means when using the second secondary battery. In Claim 1, The said display part has a liquid crystal element and an organic EL element,
An electronic device that controls the liquid crystal element of the display unit so that the number of display rewrites per unit time is reduced when the second secondary battery is used. 3. The electronic device according to claim 1, wherein when the second secondary battery is used, power supply to a functional circuit other than the communication unit is stopped. The electronic device according to claim 1, wherein the first secondary battery includes a plurality of secondary battery cells. In any one of Claims 1 thru | or 4, It has a supply means for charging the said 1st secondary battery or the said 2nd secondary battery,
The supply means is an electronic device having an antenna for wireless power feeding. 5. The method according to claim 1, further comprising power generation means for charging the first secondary battery or the second secondary battery.
The power generation means is an electronic device having a solar battery. A display unit having a liquid crystal element and an organic EL element;
Communication means;
A secondary battery for supplying power to the display unit;
Means for detecting the remaining amount of the secondary battery;
Means for disabling or stopping execution of an application that contributes to a change in the display image of the display unit when the detection unit detects that the remaining amount of the secondary battery is below a threshold power. ,
An electronic device capable of communicating at least once by the communication means in a state where the remaining amount of the secondary battery is lower than a threshold power. The electronic device according to claim 7, wherein power supply to a functional circuit other than the communication unit is stopped when a remaining amount of the secondary battery is lower than a threshold power. In Claim 7 or Claim 8, it further has supply means for charging the secondary battery,
The supply means is an electronic device having an antenna for wireless power feeding.