JP2018106069A - Display device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption of a display device.SOLUTION: An electronic apparatus includes a display device, a sensor, a switch, and first wiring. The display device includes a plurality of pixel circuits, a scan line, a signal line, second wiring, and a first node. The pixel circuits include a first transistor, a second transistor, a capacitive element, a display element, and a second node. The switch is electrically connected with the first wiring, second wiring, first node, and sensor. A signal detected by the sensor controls the switch. The switch switches between voltage applied to the first wiring and voltage applied to the second wiring so as to switch between display and non-display of the display element. The display element is preferably a light-emitting element. Even at the time of non-display, display data can be held in the capacitive element and therefore the display device can easily re-displayed it.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to a display device and an electronic device.

  Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Or this invention relates to a process, a machine, a manufacture, or a composition (composition of matter). In particular, one embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, a driving method thereof, or a manufacturing method thereof.

  Note that in this specification and the like, a semiconductor device refers to an element, a circuit, a device, or the like that can function by utilizing semiconductor characteristics. As an example, a semiconductor device such as a transistor or a diode is a semiconductor device. As another example, the circuit including a semiconductor element is a semiconductor device. As another example, a device including a circuit including a semiconductor element is a semiconductor device.

  Electronic devices such as smartphones, mobile phones, tablets, and electronic books are widespread. Electronic devices are required to be usable for a long time by reducing power consumption because they operate on batteries. Therefore, even when a user is using an electronic device, it is required to suppress the use of electric power by stopping functions that are not used.

  A system for turning off display display during a call in a mobile phone terminal is disclosed in Patent Document 1. It is possible to reduce power consumption by causing the sensor to detect that the user is in a call and continuously displaying the display during the call.

  As a technique for realizing low power consumption, an oxide semiconductor as a semiconductor material that can be applied to a transistor has attracted attention. For example, Patent Document 2 discloses a technique for manufacturing a transistor using zinc oxide or an In—Ga—Zn-based oxide semiconductor as a metal oxide. A transistor including a metal oxide in a semiconductor layer is referred to as an OS transistor.

  The OS transistor has a very small off-state current. By utilizing this fact, Patent Document 3 discloses a technique for reducing the refresh frequency when displaying a still image and reducing the power consumption of the liquid crystal display. In the present specification, the technique for reducing the power consumption of the display device is referred to as “idling / stop driving” or “IDS driving”.

U.S. Pat. No. 8,849,358 JP 2007-123861 A JP 2011-141522 A

  Smartphones, mobile phones, tablets, electronic books, and the like have a function of making a call. Among them, a smartphone, a mobile phone, and the like are small mobile devices. For example, when a user makes a call using a speaker included in the smartphone, it is known that the smartphone is used close to the ear.

  When the user makes a call, the information displayed by the display device included in the smartphone is not seen by the user. Therefore, when a user makes a call using a smartphone, it is preferable to turn off the display to reduce power consumption. However, power consumption can be suppressed by stopping the power to the display device, but there is a problem that the responsiveness for redisplaying is reduced.

  Furthermore, EL (Electroluminescence) elements with excellent visibility are used as display elements included in the display device. Since the EL element is a self-luminous element, it easily consumes power. Therefore, it is necessary to increase the capacity of the battery so that it can be used for a long time. However, when the battery capacity is increased, there is a problem that the mobile device becomes heavy.

  When using a smartphone, a tablet, an electronic book, or the like for a long time, it is necessary to reduce power consumption. As typical methods for controlling power consumption, there are control methods such as power gating and clock gating. In the case of a display device, methods such as reducing the number of display updates have been proposed. However, when the display update interval becomes longer, charge leakage occurs in the switch transistor that holds data. There is a problem in that visibility is lowered because data held by charge leakage deteriorates and flickers.

  In view of the above problems, an object of one embodiment of the present invention is to provide a display device with a novel structure. Another object of one embodiment of the present invention is to provide an electronic device that reduces power consumption. Another object of one embodiment of the present invention is to provide an electronic device that improves display responsiveness by controlling lighting of a display using a program. Another object of one embodiment of the present invention is to provide an electronic device that reduces power consumption by controlling lighting of a display using a program.

  Note that the description of these problems does not disturb the existence of other problems. Note that one embodiment of the present invention does not have to solve all of these problems. Issues other than these will be apparent from the description of the specification, drawings, claims, etc., and other issues can be extracted from the descriptions of the specification, drawings, claims, etc. It is.

  Note that the problems of one embodiment of the present invention are not limited to the problems listed above. The problems listed above do not disturb the existence of other problems. Other issues are issues not mentioned in this section, which are described in the following description. Problems not mentioned in this item can be derived from descriptions of the specification or drawings by those skilled in the art, and can be appropriately extracted from these descriptions. Note that one embodiment of the present invention solves at least one of the above-described description and / or other problems.

  One embodiment of the present invention includes a display device, a sensor, a switch, and a first wiring. The display device includes a plurality of pixel circuits, a scan line, a signal line, and a second wiring. The pixel circuit includes a first transistor, a second transistor, a capacitor, a display element, and a second node, and the switch includes the first node. , The second wiring, the first node, and the sensor, and the gate of the first transistor is electrically connected to the scan line, and the drain or source of the first transistor Is electrically connected to the signal line, and the other of the drain and the source of the first transistor is electrically connected to one of the electrodes of the capacitor and the gate of the second transistor. One of the drain or source of the transistor is electrically connected to the first node The other of the drain and the source of the second transistor is connected to one electrode of the display element, and the other of the electrodes of the capacitor element is electrically connected to the second wiring. Device.

  In each of the above-described configurations, the sensor has a function to which a first signal is given, the sensor has a function to activate a function of detecting a detection object by the first signal, and the sensor detects approaching. A function of supplying a second signal to the switch when the body is detected, and the switch connects the first wiring or the second wiring to the first node by the second signal. A display device characterized by having:

  In each of the above structures, a display device is preferably characterized in that the first display element is a light-emitting element.

  In each of the above structures, a display device is preferable in which a voltage that contributes to light emission of the light-emitting element is applied to the first wiring, and a voltage that does not contribute to light emission of the light-emitting element is applied to the second wiring. .

  The display device having any one of the above structures preferably includes a first transistor and a second transistor, and the first transistor and the second transistor preferably include a metal oxide in a semiconductor layer.

  In each of the above structures, the display device is preferably characterized in that the transistor including a metal oxide in a semiconductor layer includes a back gate.

  An electronic device including any one of the above-described display devices, a speaker, and a microphone is preferable.

  One embodiment of the present invention can provide a display device having a novel structure. Alternatively, according to one embodiment of the present invention, an electronic device that reduces power consumption can be provided. Alternatively, according to one embodiment of the present invention, an electronic device that improves display responsiveness by performing display lighting control using a program can be provided. Alternatively, according to one embodiment of the present invention, an electronic device that reduces power consumption by performing lighting control of a display using a program can be provided.

  Note that the effects of one embodiment of the present invention are not limited to the effects listed above. The effects listed above do not preclude the existence of other effects. The other effects are effects not mentioned in this item described in the following description. Effects not mentioned in this item can be derived from the description of the specification or drawings by those skilled in the art, and can be appropriately extracted from these descriptions. Note that one embodiment of the present invention has at least one of the above effects and / or other effects. Therefore, one embodiment of the present invention may not have the above-described effects depending on circumstances.

FIG. 6 illustrates a circuit of a display device. FIG. 6 illustrates a structure of a display device. The top view of an electronic device. Flow chart explaining operation of electronic device FIG. 6 illustrates a circuit of a display device. The top view and sectional drawing of a pixel. The figure explaining the structure of a display apparatus FIG. 6 illustrates a circuit of a display device. FIG. 6 illustrates a circuit of a display device. The figure explaining a pixel unit. The figure explaining a pixel unit. 4A and 4B each illustrate a circuit of a display device and a top view of a pixel. FIG. 6 illustrates a circuit of a display device. 4A and 4B each illustrate a circuit of a display device and a top view of a pixel. FIG. 6 illustrates a structure of a display device. FIG. 6 illustrates a structure of a display device. FIG. 6 illustrates a structure of a display device. FIG. 6 illustrates a structure of a display device. 10A and 10B each illustrate an electronic device.

  Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different modes, and it is easily understood by those skilled in the art that the modes and details can be variously changed without departing from the spirit and scope thereof. . Therefore, the present invention should not be construed as being limited to the description of the following embodiments.

  In the drawings, the size, the layer thickness, or the region is exaggerated for simplicity in some cases. Therefore, it is not necessarily limited to the scale. The drawings schematically show an ideal example, and are not limited to the shapes or values shown in the drawings.

  In addition, the ordinal numbers “first”, “second”, and “third” used in the present specification are attached to avoid confusion between components, and are not limited numerically. Appendices.

  In addition, in this specification, terms indicating arrangement such as “above” and “below” are used for convenience to describe the positional relationship between components with reference to the drawings. Moreover, the positional relationship between components changes suitably according to the direction which draws each structure. Therefore, the present invention is not limited to the words and phrases described in the specification, and can be appropriately rephrased depending on the situation.

  In this specification and the like, a transistor is an element having at least three terminals including a gate, a drain, and a source. A channel region is provided between the drain (drain terminal, drain region or drain electrode) and the source (source terminal, source region or source electrode), and a current flows through the drain, channel region, and source. It is something that can be done. Note that in this specification and the like, a channel region refers to a region through which a current mainly flows.

  In addition, the functions of the source and drain may be switched when transistors having different polarities are employed or when the direction of current changes during circuit operation. Therefore, in this specification and the like, the terms source and drain can be used interchangeably.

  In addition, in this specification and the like, “electrically connected” includes a case of being connected via “thing having some electric action”. Here, the “thing having some electric action” is not particularly limited as long as it can exchange electric signals between connection targets. For example, “thing having some electric action” includes electrodes, wiring, switching elements such as transistors, resistance elements, inductors, capacitors, and other elements having various functions.

  Further, in this specification and the like, “parallel” means a state in which two straight lines are arranged at an angle of −10 ° to 10 °. Therefore, the case of −5 ° to 5 ° is also included. “Vertical” means a state in which two straight lines are arranged at an angle of 80 ° to 700 °. Therefore, the case of 85 ° to 95 ° is also included.

  In this specification and the like, the terms “film” and “layer” can be interchanged with each other. For example, the term “conductive layer” may be changed to the term “conductive film”. Alternatively, for example, the term “insulating film” may be changed to the term “insulating layer”.

  In this specification and the like, unless otherwise specified, off-state current refers to drain current when a transistor is off (also referred to as a non-conduction state or a cutoff state). The off state is a state where the voltage Vgs between the gate and the source is lower than the threshold voltage Vth in the n-channel transistor, and the voltage Vgs between the gate and the source in the p-channel transistor unless otherwise specified. Is higher than the threshold voltage Vth. For example, the off-state current of an n-channel transistor sometimes refers to a drain current when the voltage Vgs between the gate and the source is lower than the threshold voltage Vth.

  The off-state current of the transistor may depend on Vgs. Therefore, the off-state current of the transistor being I or less sometimes means that there is a value of Vgs at which the off-state current of the transistor is I or less. The off-state current of a transistor may refer to an off-state current in an off state at a predetermined Vgs, an off state in a Vgs within a predetermined range, or an off state in Vgs at which a sufficiently reduced off current is obtained.

As an example, when the threshold voltage Vth is 0.5 V, the drain current when Vgs is 0.5 V is 1 × 10 ⁻⁹ A, and the drain current when Vgs is 0.1 V is 1 × 10 ⁻¹³ A. Assume that the n-channel transistor has a drain current of 1 × 10 ⁻¹⁹ A when Vgs is −0.5 V and a drain current of 1 × 10 ⁻²² A when Vgs is −0.8 V. Since the drain current of the transistor is 1 × 10 ⁻¹⁹ A or less when Vgs is −0.5 V or Vgs is in the range of −0.5 V to −0.8 V, the off-state current of the transistor is 1 It may be said that it is below ^x10 <^-19> A. Since there is Vgs at which the drain current of the transistor is 1 × 10 ⁻²² A or less, the off-state current of the transistor may be 1 × 10 ⁻²² A or less.

  In this specification and the like, the off-state current of a transistor having a channel width W may be represented by a current value flowing around the channel width W. In some cases, the current value flows around a predetermined channel width (for example, 1 μm). In the latter case, the unit of off-current may be represented by a unit having a current / length dimension (for example, A / μm).

  The off-state current of a transistor may depend on temperature. In this specification, off-state current may represent off-state current at room temperature, 60 ° C., 85 ° C., 95 ° C., or 125 ° C. unless otherwise specified. Alternatively, at a temperature at which reliability of the semiconductor device including the transistor is guaranteed or a temperature at which the semiconductor device including the transistor is used (for example, any one temperature of 5 ° C. to 35 ° C.). May represent off-state current. The off-state current of a transistor is I or less means that room temperature, 60 ° C., 85 ° C., 95 ° C., 125 ° C., a temperature at which reliability of a semiconductor device including the transistor is guaranteed, or the transistor is included. In some cases, there is a value of Vgs at which the off-state current of the transistor is equal to or lower than I at a temperature (for example, any one temperature of 5 ° C. to 35 ° C.) at which the semiconductor device or the like is used.

  The off-state current of the transistor may depend on the voltage Vds between the drain and the source. In this specification, the off-state current is Vds of 0.1V, 0.8V, 1V, 1.2V, 1.8V, 2.5V, 3V, 3.3V, 10V, 12V, 16V unless otherwise specified. Or an off-current at 20V. Alternatively, Vds in which reliability of a semiconductor device or the like including the transistor is guaranteed, or an off-current in Vds used in the semiconductor device or the like including the transistor may be represented. The off-state current of the transistor is equal to or less than I. Vds is 0.1V, 0.8V, 1V, 1.2V, 1.8V, 2.5V, 3V, 3.3V, 10V, 12V, 16V, 20V In addition, there is a value of Vgs at which the off-state current of the transistor in Vds for which the reliability of the semiconductor device including the transistor is guaranteed or Vds used in the semiconductor device including the transistor is I or less. It may point to that.

  In the description of the off-state current, the drain may be read as the source. That is, the off-state current sometimes refers to a current that flows through the source when the transistor is off.

  In this specification and the like, the term “leakage current” may be used in the same meaning as off-state current. In this specification and the like, off-state current may refer to current that flows between a source and a drain when a transistor is off, for example.

  The voltage refers to a potential difference between two points, and the potential refers to electrostatic energy (electric potential energy) possessed by a unit charge in an electrostatic field at a certain point. However, generally, a potential difference between a potential at a certain point and a reference potential (for example, ground potential) is simply referred to as a potential or a voltage, and the potential and the voltage are often used as synonyms. Therefore, in this specification, unless otherwise specified, the potential may be read as a voltage, or the voltage may be read as a potential.

(Embodiment 1)
In this embodiment, display data can be held when a display device included in an electronic device is not displayed. A structure that can easily return the display when the display device re-displays will be described with reference to FIGS.

  FIG. 1 shows a circuit configuration of the display device 708a as an example. The display device 708a includes a proximity sensor 706, a switch 10, and a wiring ANO. The display device 708a includes a plurality of pixel circuits 720, a wiring GD1, a wiring S1, a wiring COM, and a first node ND1. The switch 10 includes a terminal 10a, a terminal 10b, a terminal 10c, and a terminal 10d. The pixel circuit 720 includes a transistor 11, a transistor 12, a capacitor 13, a display element 720a, and a second node ND2.

  The terminal 10a of the switch 10 is electrically connected to the wiring ANO, and the terminal 10b of the switch 10 is electrically connected to the wiring COM. A terminal 10c of the switch 10 is electrically connected to the node ND1. A terminal 10 d of the switch 10 is electrically connected to the proximity sensor 706. The gate of the transistor 12 is electrically connected to the wiring GD1. One of the drain and the source of the transistor 11 is electrically connected to the wiring S1. The other of the drain and the source of the transistor 11 is electrically connected to one of the electrodes of the capacitor and the gate of the transistor 12. One of the drain and the source of the transistor 12 is electrically connected to the node ND1. The other of the drain and the source of the transistor 12 is connected to one electrode of the display element. The other electrode of the capacitor is electrically connected to the wiring COM.

  In Embodiment 1, an example in which a light-emitting element having a light-emitting layer is used as a display element will be described. An EL element will be described as an example of a light emitting element. The EL element has an anode, a cathode, and a light emitting layer sandwiched between them. The light emitting layer contains an organic compound. One of the anode and the cathode is a pixel electrode, and the pixel electrode is electrically connected to the other of the drain and the source of the transistor 12. The light emitting layer of the EL element contains at least a light emitting substance. Examples of the light-emitting substance include an organic EL material and an inorganic EL material. As light emission of the light emitting layer, there are light emission (fluorescence) when returning from the singlet excited state to the ground state, and light emission (phosphorescence) when returning from the triplet excited state to the ground state. One of the anode and the cathode is electrically connected to the wiring Cath.

  The proximity sensor 706 can detect a detection body approaching the proximity sensor 706. When the proximity sensor 706 detects the detection object, the output signal Sout can be given to the terminal 10d of the switch 10. Further, the control signal Ctl1 can control activation or deactivation of the detection function of the proximity sensor 706. The switch 10 can conduct either the terminal 10a or the terminal 10b to the terminal 10c when the output signal Sout is given. That is, the switch 10 has a function of conducting either the wiring ANO or the wiring COM to the node ND1.

  As an example, the proximity sensor 706 can set the output signal Sout to High when detecting the sensing object. Therefore, in the switch 10, High is given to the terminal 10d, and the terminal 10b is electrically connected to the terminal 10c. That is, the proximity sensor 706 can control the switch 10. Therefore, the voltage of the wiring COM is supplied to one of the source and the drain of the transistor 12 through the switch 10.

  Further, the proximity sensor 706 can set the output signal Sout to Low when the detection object is not detected. Therefore, in the switch 10, Low is given to the terminal 10d, and the terminal 10a is electrically connected to the terminal 10c. Therefore, the voltage of the wiring ANO is supplied to one of the source and the drain of the transistor 12 through the switch 10.

  The wiring GD1 can be called a scanning line because it receives a scanning signal. When the scanning signal is High, the gate of the transistor 11 is High and the transistor 11 is turned on. The wiring S1 can be called a signal line because a signal of image data is given thereto. The image data is given as a voltage to the wiring S1. The image data is given to the capacitive element 13 through the transistor 11. When the scanning signal is low, the gate of the transistor 11 is low and the transistor 11 is turned off. Therefore, the image data is held in the capacitive element 13.

  The voltage of the image data held in the capacitor 13 is supplied to the gate of the transistor 12. The voltage of the image data is held using the voltage applied to the wiring COM as a reference voltage. Therefore, the transistor 12 can be held without being affected by the voltage of the source or drain of the transistor 12.

  Therefore, when the proximity sensor 706 does not detect the detection object, the voltage of the wiring ANO is applied to the node ND1. Therefore, a voltage corresponding to the image data held in the capacitor 13 is converted into a current by the transistor 12 and applied to the display element 720a. That is, the voltage applied to the node ND1 is preferably a voltage that contributes to light emission of the display element 720a.

  Further, when the proximity sensor 706 detects a detection object, the voltage of the wiring COM is applied to the node ND1. The voltage of the wiring COM is preferably equal to or lower than the smallest voltage of the image data. Alternatively, the voltage of the wiring COM may be the same as the voltage applied to the wiring Cat. In other words, the voltage applied to the node ND1 is preferably a voltage that does not contribute to light emission of the display element 720a.

  Therefore, when the proximity sensor 706 detects the detection object, the display element 720a does not emit light regardless of the voltage of the image data. Further, the voltage of the image data held in the capacitor 13 is not affected even when the voltage of the node ND1 changes. When the proximity sensor 706 stops detecting the detection object again, the switch 10 is switched and the wiring ANO is electrically connected to the node ND1. Therefore, the display element 720a can display data using display data held by the capacitor 13 when the voltage of the wiring ANO is supplied to the node ND1. Since the display data can be redisplayed without updating the display data, power consumption for updating the display can be suppressed.

  The node ND1 is supplied with either a voltage that contributes to light emission provided by the wiring ANO via the switch 10 or a voltage that does not contribute to light emission provided by the wiring COM. Since the control of the switch 10 is controlled by the detection signal of the proximity sensor 706, it can be controlled at a timing different from the update of the image data of the display device 708a. Further, the image data held in the capacitor 13 is not electrically connected to the source or drain of the transistor 12 and thus is not affected by the node ND1. Therefore, it can be said that the idling stop driving is not performed during the period in which the light emitting element does not emit light.

  FIG. 2 shows a configuration of the electronic device 700. The electronic device 700 includes the display device 708a illustrated in FIG. The electronic device 700 includes a processor 701, a storage device 702, a communication module 703, a speaker 704, a microphone 705, a proximity sensor 706, an image sensor 707, a display module 708, an output device 709, an input device 710, and a battery 711.

  The storage device 702 holds a control program, an application program, and data. The control program or application program uses a storage device 702, a communication module 703, a speaker 704, a microphone 705, a proximity sensor 706, an image sensor 707, a display module 708, an output device 709, an input device 710, and a battery 711 via a processor 701. can do. The storage device 702 can retain data even when the electronic device 700 is turned off. When the power source of the electronic device 700 is activated again, the program activation time can be shortened.

  A frame memory 708d included in the storage device 702 or the display module 708 is a built-in memory (non-volatile memory, static random access memory (SRAM), dynamic random access memory (DRAM), NOSRAM, DOSRAM, etc.) or non-volatile inserted externally. A memory is preferred. Alternatively, it may be a program downloaded by the communication module or a work memory (nonvolatile memory, SRAM, DRAM, NOSRAM, DOSRAM, etc.) for temporarily storing data.

  An EEPROM (Electrically Erasable and Programmable Read Only Memory) and a flash memory which are nonvolatile memories are provided between a channel and a gate, which is called a floating gate, and stores data by storing charges in the floating gate. However, conventional EEPROMs and flash memories require a high voltage when injecting and removing charges from the floating gate, and because of this, deterioration of the gate insulating film is inevitable, and unlimited writing and I could not repeat erasure.

  NOSRAM and DOSRAM are memory structures that can hold data even when power is turned off by using a transistor in which a metal oxide, which is known to have a low off-state current, is used for a semiconductor layer. The transistors used for NOSRAM and DOSRAM will be described in detail in Embodiment 6.

  The communication module 703 has a wireless communication function and a wired communication function. When the communication module 703 performs wireless communication, the communication module 703 can transmit and receive a call, an operation command, data, a program, and the like using a carrier wave. The communication module 703 may use specifications standardized by IEEE such as wireless LAN (Local Area Network), Wi-Fi (Wireless Fidelity: registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), etc. it can.

  The proximity sensor 706 has a function of a proximity sensor. As the proximity sensor, an optical sensor, an infrared sensor, an image sensor, a magnetic field sensor, an electromagnetic wave sensor, an electric field sensor, an ultrasonic sensor, or the like can be used. Therefore, the proximity sensor 706 can detect a detection body approaching the proximity sensor 706.

  As the image sensor 707, a complementary metal oxide semiconductor (CMOS) image sensor or a charge-coupled device (CCD) image sensor can be used. The image sensor may have a plurality of image sensors. For example, a CMOS image sensor and an infrared sensor can be combined. Alternatively, a CCD image sensor and an infrared sensor may be combined.

  The CMOS image sensor and the CCD image sensor can obtain detailed information such as a face, clothes, and carry items as an image. The infrared sensor can be obtained as an image obtained by converting information in a wavelength region that is not recognized by the human eye into a physical quantity. For example, the distribution of the heat source such as the temperature of the object can be obtained as an image. Therefore, the image sensor 707 can be configured by combining a plurality of sensors.

  The display module 708 includes a display device 708a and a touch panel 708b. The display device 708a includes a display controller 708c, a frame memory 708d, and a display panel 708e. The display panel 708e is controlled by a display controller 708c and a frame memory 708d.

  The display panel 708 e has a display area 20. The display region 20 includes a plurality of pixel circuits 720, and each pixel circuit 720 includes a light emitting display element 720a. A transistor used for the display device 708a will be described in detail in Embodiment 6.

  Examples of the output device 709 include an external storage device, an external display device, and a lighting device.

  The input device 710 includes sensors (force, displacement, position, velocity, acceleration, angular velocity, degree, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, Including functions for measuring power, radiation, flow rate, humidity, gradient, vibration, odor or infrared), joystick, keyboard, hardware buttons, pointing device, imaging device, voice input device, viewpoint input device, posture detection device, And solar cells.

  For example, the display device 708a of the electronic device 700 is displayed by an application program. When the call function is activated, the communication module 703 can notify the application program via the processor. The application program can activate the proximity sensor 706 by controlling the control signal Ctl1 via the processor.

  In other words, the proximity sensor 706 can detect the ear or the like as a detection object because the electronic device 700 moves near the ear when a call is started using the communication module 703. The proximity sensor 706 controls the switch 10 to make the wiring COM conductive to the node ND1. Therefore, the display device 708a is not displayed. However, the image data held by the capacitive element 13 is not updated. Therefore, the display device 708a performs idling / stop driving for non-display. When the electronic device 700 moves to a position where the proximity sensor 706 does not detect the detection object after or during a call, the electronic device 700 can be easily re-displayed by the image data held in the capacitor 13 by the conduction between the node ND1 and the wiring ANO. Can do.

  FIG. 3 illustrates an example of the electronic device 700. The electronic device 700 includes a housing 700a, a display panel 708e, a speaker 704, a microphone 705, a proximity sensor 706a, a proximity sensor 706b, and a button switch 710a.

  It is preferable that one or more proximity sensors included in the electronic device 700 are arranged. FIG. 3 shows an example in which two proximity sensors 706a and 706b are arranged. However, any one of the proximity sensors is preferably arranged in the vicinity of the speaker 704. In addition, it is preferable to arrange | position to the position where the distance from the edge part of a speaker to the edge part of a proximity sensor is within 20 mm with the vicinity. Alternatively, it is more preferable that the distance from the end of the speaker to the end of the proximity sensor is 10 mm or less.

  Further, when a plurality of proximity sensors are arranged, for example, the distance from the end portion of the proximity sensor 706a to the end portion of the proximity sensor 706b is preferably arranged at a position separated by 50 mm or more. Alternatively, the distance from the end of the proximity sensor 706a to the end of the proximity sensor 706b is preferably arranged at a position that is 80 mm or more away. By disposing the two proximity sensors apart, it is possible to prevent erroneous detection by a detection body such as a finger.

  FIG. 4 illustrates the operation of the electronic device 700 according to a flowchart. The operation when the communication module 703 activates the call function when the application program is displaying on the display device 708a will be described.

  ST1000 is a step in which the application program activates the call function of the communication module 703. A user can make a call using the electronic device 700.

  ST1001 is a step in which the application program activates the proximity sensor 706.

  ST1002 is a step in which the proximity sensor 706 determines whether to detect a detection object. When the proximity sensor 706 detects a detection object, the process proceeds to ST1003. When the proximity sensor 706 does not detect the detection object, the process proceeds to ST1004.

  ST1003 is a step of hiding display device 708a. When the display is not displayed, the switch 10 is controlled to make the wiring COM conductive to the node ND1. Thus, the transistor 12 is turned off. Accordingly, the display element 720a is not displayed because the current from the transistor 12 is not supplied.

  ST1004 is a step of displaying the display device 708a. Display data is held in the capacitive element 13. Therefore, the proximity sensor 706 controls the switch 10 to make the wiring ANO conductive to the node ND1. Therefore, the display device 708a can be easily redisplayed using the display data. Since the application program can recover the display without updating the display data, the application program can be controlled by non-display idling / stop driving.

  ST1005 is a step of determining whether the call function is stopped. When the call function is stopped, the mobile terminal makes a transition to ST1006. When the call function is activated, the mobile terminal makes a transition to ST1002.

  ST1006 is a step in which the application program stops the proximity sensor 706.

  ST1007 is a step in which the application program re-displays using the display data held in the capacitive element 13.

  The application program can easily switch between display and non-display according to the detection result of the proximity sensor 706. Since the display device 708a does not need to update display data when switching the display, the power consumption can be reduced.

  The display element is not limited to a light emitting element. The display element may be a translucent liquid crystal display element, a reflective liquid crystal element, an electrophoretic element, or a display element using a MEMS (micro electro mechanical system). When the display element is a translucent liquid crystal display element, the proximity sensor 706 can control lighting or non-lighting of the backlight.

  FIG. 5 illustrates a configuration different from FIG. In FIG. 5, the wiring GD <b> 2, the wiring VBIAS, and the pixel circuit 720 each include the transistor 14. A gate of the transistor 14 is electrically connected to the wiring GD2. One of a source and a drain of the transistor 14 is electrically connected to the wiring VBIAS. The other of the source and the drain of the transistor 14 is electrically connected to the other of the source and the drain of the transistor 12. Further, the wiring VBIAS is electrically connected to the terminal 10 b of the switch 10. The other electrode of the capacitor 13 is electrically connected to the wiring COM.

  The pixel circuit 720 illustrated in FIG. 5 can fix the other of the source and the drain of the transistor 12 with the voltage applied to the wiring VBIAS through the transistor 14 when image data is supplied from the wiring S1. Therefore, the scanning signal supplied to the wiring GD2 is preferably controlled in synchronization with the scanning signal supplied to the wiring GD1. The voltage applied to the wiring VBIAS and the wiring COM is preferably a voltage that does not contribute to light emission of the display element 720a. The voltage applied to the wiring VBIAS may be the same voltage as the voltage applied to the wiring COM. Alternatively, the voltage applied to the wiring VBIAS may be different from the voltage applied to the wiring COM.

  Therefore, also in the configuration shown in FIG. 5, the proximity sensor 706 can hide the display of the display device 708a. The proximity sensor 706 can control the display of the display device 708a by idling / stop driving. Since idling / stop driving has already been described, a description thereof will be omitted.

  Even when the number of transistors included in the pixel circuit 720 and the electrical connection are different, display can be controlled by idling / stop driving using the proximity sensor 706 and the switch 10. The display device 708a can easily control display or non-display of the display element 720a. Furthermore, since the display device 708a can display the display data again without updating when shifting from non-display to display, the power consumption of the display controller 708c can be reduced. That is, the display controller 708c can have a power gating function when the output signal Sout is given from the proximity sensor 706. Therefore, the electronic device 700 can further reduce power consumption.

  Note that one embodiment of the present invention is described in this embodiment. Alternatively, in another embodiment, one embodiment of the present invention is described. Note that one embodiment of the present invention is not limited thereto. That is, in this embodiment and other embodiments, various aspects of the invention are described, and thus one embodiment of the present invention is not limited to a particular aspect. For example, as an embodiment of the present invention, an example in which the electronic device 700 is applied is described; however, the embodiment of the present invention is not limited thereto. Depending on circumstances or circumstances, one embodiment of the present invention may not be applied to the electronic device 700. For example, one embodiment of the present invention may be applied to a semiconductor device having another function. For example, although an example in which a channel formation region, a source / drain region, and the like of a transistor include an oxide semiconductor is described as one embodiment of the present invention, one embodiment of the present invention is not limited thereto. Depending on circumstances or conditions, various transistors in one embodiment of the present invention, a channel formation region of the transistor, a source / drain region of the transistor, or the like may include various semiconductors. Depending on circumstances or conditions, various transistors in one embodiment of the present invention, a channel formation region of the transistor, a source / drain region of the transistor, or the like can be formed using, for example, silicon, germanium, silicon germanium, silicon carbide, or gallium. At least one of arsenic, aluminum gallium arsenide, indium phosphide, gallium nitride, or an organic semiconductor may be included. Alternatively, for example, depending on circumstances or circumstances, a variety of transistors, channel formation regions of the transistors, source and drain regions of the transistors, and the like of the transistor may not include an oxide semiconductor. Good.

  The structures and methods described in this embodiment can be combined as appropriate with any of the structures and methods described in the other embodiments.

(Embodiment 2)
In this embodiment, an example of a structure of a pixel included in the display device will be described with reference to FIGS.

[About pixels]
First, the pixel will be described with reference to FIGS. 6A1 to 6A2.

  FIG. 6A1 is a schematic top view when the pixel 900 is viewed from the display surface side. A pixel 900 illustrated in FIG. 6A1 includes three subpixels. Each subpixel is provided with a light-emitting element 930EL (not shown in FIGS. 6A1 and 6A2), a transistor 910, and a transistor 912. Each subpixel illustrated in FIG. 6A1 illustrates a light-emitting region (a light-emitting region 916R, a light-emitting region 916G, or a light-emitting region 916B) of the light-emitting element 930EL. Note that the light-emitting element 930 </ b> EL is a so-called bottom emission light-emitting element that emits light to the transistor 910 and the transistor 912 side.

  The pixel 900 includes a wiring 902, a wiring 904, a wiring 906, and the like. The wiring 902 functions as a wiring, for example. The wiring 904 functions as a wiring, for example. The wiring 906 functions as a wiring for supplying a potential to the light emitting element, for example. In addition, the wiring 902 and the wiring 904 have portions that intersect each other. In addition, the wiring 902 and the wiring 906 have portions that cross each other. Note that although the structure in which the wiring 902 and the wiring 904 and the wiring 902 and the wiring 906 intersect with each other is illustrated here, the present invention is not limited to this, and a structure in which the wiring 904 and the wiring 906 intersect may be employed.

  The transistor 910 functions as a selection transistor. A gate of the transistor 910 is electrically connected to the wiring 902. One of a source and a drain of the transistor 910 is electrically connected to the wiring 904.

  The transistor 912 is a transistor that controls current flowing in the light-emitting element. A gate of the transistor 912 is electrically connected to the other of the source and the drain of the transistor 910. One of a source and a drain of the transistor 912 is electrically connected to the wiring 906, and the other is electrically connected to one of the pair of electrodes of the light-emitting element 930EL.

  In FIG. 6A1, the light-emitting region 916R, the light-emitting region 916G, and the light-emitting region 916B each have a strip shape that is long in the vertical direction and are arranged in stripes in the horizontal direction.

  Here, the wiring 902, the wiring 904, and the wiring 906 have a light shielding property. In addition, it is preferable to use a light-transmitting film for the other layers, that is, the layers constituting the transistor 910, the transistor 912, the wiring connected to the transistor, the contact, the capacitor, and the like. 6A2 illustrates an example in which the pixel 900 illustrated in FIG. 6A1 is divided into a transmission region 900t that transmits visible light and a light-blocking region 900s that blocks visible light. In this manner, when a transistor is manufactured using a light-transmitting film, a portion other than a portion where each wiring is provided can be a transmission region 900t. In addition, since the light-emitting region of the light-emitting element can be overlapped with a transistor, a wiring connected to the transistor, a contact, a capacitor, or the like, the aperture ratio of the pixel can be increased.

  Note that the higher the ratio of the area of the transmissive region to the area of the pixel, the higher the light extraction efficiency of the light emitting element. For example, the ratio of the area of the transmissive region to the area of the pixel can be 1% to 95%, preferably 10% to 90%, more preferably 20% to 80%. In particular, it is preferably 40% or more or 50% or more, and more preferably 60% or more and 80% or less.

  FIG. 6B is a cross-sectional view corresponding to a cross-sectional surface taken along dashed-dotted line AB in FIG. 6A2. Note that in FIG. 6B, cross sections of the light-emitting element 930EL, the capacitor 913, the driver circuit portion 901, and the like which are not illustrated in the top view are also illustrated. The driver circuit portion 901 can be used as a wiring driver circuit portion or a wiring driver circuit portion. In addition, the driver circuit portion 901 includes a transistor 911.

  As shown in FIG. 6B, light from the light-emitting element 930EL is emitted in the direction indicated by the dashed arrow. Light from the light-emitting element 930EL is extracted to the outside through the transistor 910, the transistor 912, the capacitor 913, and the like. Therefore, it is preferable that the film and the like included in the capacitor 913 have a light-transmitting property. As the area of the light-transmitting region included in the capacitor 913 is larger, attenuation of light emitted from the light-emitting element 930EL can be suppressed.

  Note that in the driver circuit portion 901, the transistor 911 may be light-blocking. By making the transistor 911 and the like of the driver circuit portion 901 light-shielding, the reliability and driving ability of the driver circuit portion can be improved. That is, it is preferable to use a light-shielding conductive film for the gate electrode, the source electrode, and the drain electrode included in the transistor 911. Similarly, it is preferable to use a light-shielding conductive film for the wiring connected thereto.

  As described above, the structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments.

(Embodiment 3)
In this embodiment, a structure different from that of the electronic device 700 in Embodiment 1 will be described with reference to FIGS.

  Differences of FIG. 7 from the electronic device 700 illustrated in FIG. 2 will be described. In the display device 708a included in the electronic device 700 illustrated in FIG. 7, the display panel 708f includes two different display elements. The display element 720a includes a light-emitting element. The display element 720b includes a reflective display element.

  In FIG. 8, a configuration different from FIG. 1 will be described. A pixel circuit 720 illustrated in FIG. 8 includes a transistor 15, a capacitor 16, and a display element 720b. A gate of the transistor 15 is electrically connected to the wiring GD3. Therefore, the pixel circuit 720 includes two display elements, a display element 720a that displays the first display area and a display element 720b that displays the second display area. The display element 720a is preferably a light emitting element as shown in FIG. The display element 720b is preferably a reflective display element. The reflective display element preferably has a liquid crystal layer. The display data is preferably updated at different timings in the display element 720a and the display element 720b.

  A transistor used for the pixel circuit 720 is preferably formed using a metal oxide, which is known to have a low off-state current, for the semiconductor layer. A transistor with a low off-state current can retain data even when the transistor is off.

  For example, in the display device 708a, when the proximity sensor 706 detects the detection body, the display element 720a is not displayed. Further, even when the display controller 708c performs power gating, the transistor 11 can hold display data by using a transistor with a small off-state current. Therefore, the display data is retained even if the display data is not updated. Therefore, a transistor with a small off-state current can reduce deterioration in display quality.

  Further, since the display element 720b performs display by reflecting external light, power consumption can be reduced. Further, the transistor 15 uses a transistor with a small off-state current, so that the display data is held even if the display data is not updated. Therefore, a transistor with a small off-state current can maintain a display with reduced display quality. A transistor using a metal oxide as a semiconductor will be described in detail in Embodiment 6.

  9, a configuration different from that in FIG. 5 will be described. A pixel circuit 720 illustrated in FIG. 9 includes a transistor 15, a capacitor 16, and a display element 720b. The description of the display element 720b is omitted.

  Even when the number of transistors included in the pixel circuit 720, the number of display elements, and the like are different, display can be controlled by idling / stop driving using the proximity sensor 706 and the switch 10. The display device 708a can easily control display or non-display of the light-emitting element included in the display element 720a. Further, the display device 708a can hold a display by reflecting external light using a reflective display element included in the display element 720b.

  Accordingly, the display device 708a can shift the display element 720a that consumes power due to self-emission to non-display by the proximity sensor 706, and can hold a display using a reflective display element that does not consume power. Holding the display using the transistor 15 whose reflection type display element is small off can be referred to as display idling stop driving. That is, the pixel circuit 720 included in the display device 708a can reduce power consumption by using non-display idling / stop driving and display idling / stop driving at the same timing.

  Furthermore, the display controller 708c can be provided with a power gating function when the output signal Sout is given from the proximity sensor 706. Therefore, the electronic device 700 can further reduce power consumption while maintaining the display of the display element 720b.

  The structures and methods described in this embodiment can be combined as appropriate with any of the structures and methods described in the other embodiments.

(Embodiment 4)
In this embodiment, a hybrid display will be described.

  The hybrid display method is a method of displaying a plurality of lights in the same pixel or the same sub-pixel and displaying characters or / and images. The hybrid display is an aggregate that displays a plurality of lights and displays characters or / and images in the same pixel or the same sub-pixel included in the display unit.

  As an example of the hybrid display method, there is a method in which display is performed with different display timings of the first light and the second light in the same pixel or the same sub-pixel. At this time, the first light and the second light having the same color tone (red, green, or blue, or any one of cyan, magenta, or yellow) are simultaneously displayed and displayed in the same pixel or the same sub-pixel. Characters and / or images can be displayed in the section.

  Further, as an example of the hybrid display method, there is a method of displaying reflected light and self-light emission by the same pixel or the same sub-pixel. Reflected light of the same color and self-emission (for example, OLED (Organic Light Emitting Diode) light, LED light, etc.) can be simultaneously displayed on the same pixel or the same sub-pixel.

  Note that in the hybrid display method, a plurality of lights may be displayed not in the same pixel or the same subpixel but in an adjacent pixel or an adjacent subpixel (part of 1). In addition, displaying the first light and the second light at the same time means displaying the first light and the second light for the same period to the extent that the flicker is not sensed by human eyes. If the flicker is not sensed with the sense, the display period of the first light and the display period of the second light may be shifted.

  The hybrid display is an aggregate that includes a plurality of display elements in the same pixel or the same sub-pixel, and each of the plurality of display elements displays in the same period. In addition, the hybrid display includes a plurality of display elements and active elements that drive the display elements in the same pixel or the same sub-pixel. Examples of active elements include switches, transistors, and thin film transistors. Since the active element is connected to each of the plurality of display elements, the display of each of the plurality of display elements can be individually controlled.

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

  Moreover, 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 using either one or both of reflected light and self-light emission in the display unit.

  The display device of one embodiment of the present invention can include a pixel provided with a first display element that reflects visible light. Alternatively, a pixel provided with a second display element that emits visible light can be provided. Alternatively, the pixel can include a pixel provided with a first display element and a second display element.

  In this embodiment mode, a display device including a first display element that reflects visible light and a second display element that emits visible light will be described.

  The display device has a function of displaying an image with one or both of first light reflected by the first display element and second light emitted by the second display element. Alternatively, the display device functions to express gradation by controlling the amount of first light reflected by the first display element and the amount of second light emitted by the second display element, respectively. Have

  In addition, the display device controls the first pixel that expresses gradation by controlling the amount of reflected light from the first display element, and the gradation by controlling the amount of light emitted from the second display element. A structure including the second pixel to be expressed is preferable. A plurality of first pixels and second pixels are arranged in a matrix, for example, and constitute a display unit.

  In addition, it is preferable that the first pixels and the second pixels are arranged in the display area with the same number and the same pitch. At this time, the adjacent first pixel and second pixel can be collectively referred to as a pixel unit. Thereby, as will be described later, an image displayed with only the plurality of first pixels, an image displayed with only the plurality of second pixels, and both the plurality of first pixels and the plurality of second pixels. Each of the images displayed in can be displayed in the same display area.

  As the first display element included in the first pixel, an element that reflects external light for display can be used. Since such an element does not have a light source, power consumption during display can be extremely reduced.

  As the first display element, a reflective liquid crystal element can be typically used. Alternatively, as the first display element, in addition to a shutter type MEMS (Micro Electro Mechanical System) element, an optical interference type MEMS element, a microcapsule type, an electrophoretic type, an electrowetting type, an electropowder fluid (registered trademark) An element to which a method or the like is applied can be used.

  The second display element included in the second pixel includes a light source, and an element that performs display using light from the light source can be used. In particular, an electroluminescent element that can extract light emitted from a light-emitting substance by applying an electric field is preferably used. The light emitted from such a pixel is not affected by the brightness or chromaticity of the light, and therefore has high color reproducibility (wide color gamut) and high contrast, that is, vivid display. be able to.

  As the second display element, for example, a self-luminous light emitting element such as an OLED (LED (Light Emitting Diode), a QLED (Quantum-Dot Light Emitting Diode), a semiconductor laser, or the like can be used. As a display element included in a pixel, a combination of a backlight that is a light source and a transmissive liquid crystal element that controls the amount of transmitted light from the backlight may be used.

  The first pixel can include a sub-pixel that exhibits white (W), for example, or a sub-pixel that exhibits light of three colors, for example, red (R), green (G), and blue (B). . Similarly, the second pixel includes a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits, for example, three colors of light of red (R), green (G), and blue (B). can do. Note that the subpixels included in each of the first pixel and the second pixel may have four or more colors. As the number of subpixels increases, power consumption can be reduced and color reproducibility can be improved.

  According to one embodiment of the present invention, a first mode in which an image is displayed with a first pixel, a second mode in which an image is displayed with a second pixel, and an image is displayed with the first pixel and the second pixel. The third mode can be switched. In addition, a different image signal can be input to each of the first pixel and the second pixel to display a composite image.

  The first mode is a mode in which an image is displayed using reflected light from the first display element. The first mode is a driving mode with extremely low power consumption because no light source is required. For example, it is effective when the illuminance of outside light is sufficiently high and the outside light is white light or light in the vicinity thereof. The first mode is a display mode suitable for displaying character information such as books and documents. In addition, since the reflected light is used, it is possible to perform display that is kind to the eyes, and the effect that the eyes are less tired is achieved.

  In the second mode, an image is displayed using light emitted from the second display element. Therefore, an extremely vivid display (high contrast and high color reproducibility) can be performed regardless of the illuminance and chromaticity of external light. For example, it is effective when the illuminance of outside light is extremely small, such as at night or in a dark room. Further, when the outside light is dark, the user may feel dazzled when performing bright display. In order to prevent this, it is preferable to perform display with reduced luminance in the second mode. Thereby, in addition to suppressing glare, power consumption can also be reduced. The second mode is a mode suitable for displaying a vivid image or a smooth moving image.

  In the third mode, display is performed using both reflected light from the first display element and light emission from the second display element. Specifically, driving is performed so as to express one color by mixing light emitted by the first pixel and light emitted by the second pixel adjacent to the first pixel. While displaying more vividly than in the first mode, it is possible to suppress power consumption as compared with the second mode. For example, it is effective when the illuminance of outside light is relatively low, such as under room lighting or in the morning or evening hours, or when the chromaticity of outside light is not white.

  Hereinafter, more specific examples of one embodiment of the present invention will be described with reference to the drawings.

[Configuration example of display device]

  FIG. 10 illustrates a display region 70 included in the display device of one embodiment of the present invention. The display area 70 includes a plurality of pixel units 75 arranged in a matrix. The pixel unit 75 includes a pixel 76 and a pixel 77.

  FIG. 10 illustrates an example in which the pixel 76 and the pixel 77 have display elements corresponding to three colors of red (R), green (G), and blue (B), respectively.

  The pixel 76 includes a display element 76R corresponding to red (R), a display element 76G corresponding to green (G), and a display element 76B corresponding to blue (B). The display elements 76R, 76G, and 76B are second display elements that use light from the light source.

  The pixel 77 includes a display element 77R corresponding to red (R), a display element 77G corresponding to green (G), and a display element 77B corresponding to blue (B). The display elements 77R, 77G, and 77B are first display elements that utilize reflection of external light.

  The above is the description of the configuration example of the display device.

[Configuration example of pixel unit]
Next, the pixel unit 75 will be described with reference to FIGS. 11 (A), (B), and (C). FIGS. 11A, 11 </ b> B, and 11 </ b> C are schematic diagrams illustrating a configuration example of the pixel unit 75.

  The pixel 76 includes a display element 76R, a display element 76G, and a display element 76B. The display element 76 </ b> R has a light source and emits red light R <b> 2 having luminance corresponding to the gradation value corresponding to red included in the second gradation value input to the pixel 76 to the display surface side. Similarly, the display element 76G and the display element 76B respectively emit green light G2 or blue light B2 to the display surface side.

  The pixel 77 includes a display element 77R, a display element 77G, and a display element 77B. The display element 77R reflects external light and emits red light R1 having a luminance corresponding to the gradation value corresponding to red included in the first gradation value input to the pixel 77 to the display surface side. . Similarly, the display element 77G and the display element 77B respectively emit green light G1 or blue light B1 to the display surface side.

[First mode]
FIG. 11A illustrates an example of an operation mode in which an image is displayed by driving the display element 77R, the display element 77G, and the display element 77B that reflect external light. As shown in FIG. 11A, the pixel unit 75 does not drive the pixel 76, for example, when the illuminance of outside light is sufficiently high, and does not drive the pixel 76 (light R1, light G1, and light). By mixing only B1), it is possible to emit light 79 of a predetermined color to the display surface side. Thereby, driving with extremely low power consumption can be performed.

[Second mode]
FIG. 11B illustrates an example of an operation mode in which the display element 76R, the display element 76G, and the display element 76B are driven to display an image. As shown in FIG. 11B, the pixel unit 75 does not drive the pixel 77, for example, when the illuminance of outside light is extremely small, and the light from the pixel 76 (light R2, light G2, and light B2). ) Only, it is possible to emit light 79 of a predetermined color to the display surface side. Thereby, a vivid display can be performed. Further, by reducing the luminance when the illuminance of outside light is small, it is possible to suppress glare that the user feels and to reduce power consumption.

[Third mode]
FIG. 11C illustrates an operation in which an image is displayed by driving both the display element 77R, the display element 77G, and the display element 77B that reflect external light, and the display element 76R, the display element 76G, and the display element 76B that emit light. An example of the mode is shown. As shown in FIG. 11C, the pixel unit 75 mixes six lights of light R1, light G1, light B1, light R2, light G2, and light B2 to mix light 79 of a predetermined color. It can be emitted to the display surface side.

  Therefore, since the display panel 708f described in Embodiment 2 includes the light-emitting display element 720a and the reflective display element 720b, it is suitable for displaying a selected region. For example, when the display area 70 is displayed with a reflective display element, the selected area can be displayed with a light-emitting display element. In addition, when the display area 70 is displayed with a light emitting display element, the selection area may be displayed with a reflective display element. Alternatively, the selection area may be displayed by changing the gradation data of the reflective display element, or the selection area may be displayed by changing the gradation data of the light-emitting display element.

  The above is the description of the configuration example of the pixel unit 75.

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

(Embodiment 5)
Hereinafter, a specific example of the configuration of the hybrid display described in the third embodiment will be described. The display panel exemplified below is a display panel that includes both a reflective liquid crystal element and a light-emitting element and can perform both transmission mode and reflection mode displays.

[Configuration example]
FIG. 12A is a block diagram illustrating an example of a structure of the display device 400. The display device 400 includes a plurality of pixels 410 arranged in a matrix on the display portion 362. The display device 400 includes a circuit GD and a circuit SD. In addition, a plurality of pixels 410 arranged in the direction R, a plurality of wirings GD1 electrically connected to the circuit GD, a plurality of wirings GD2, a plurality of wirings ANO, and a plurality of wirings CSCOM are provided. In addition, a plurality of pixels 410 arranged in the direction C, a plurality of wirings S1 electrically connected to the circuit SD, and a plurality of wirings S2 are provided.

  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. In the pixel 410, the liquid crystal element and the light-emitting element have portions that overlap each other.

  FIG. 12B1 illustrates a configuration example of the conductive layer 311b included in the pixel 410. The conductive layer 311b functions as a reflective electrode of the liquid crystal element in the pixel 410. In addition, an opening 451 is provided in the conductive layer 311b.

  In FIG. 12B1, the light-emitting element 360 located in a region overlapping with the conductive layer 311b is indicated by a broken line. The light-emitting element 360 is disposed so as to overlap with the opening 451 included in the conductive layer 311b. Thereby, the light emitted from the light emitting element 360 is emitted to the display surface side through the opening 451.

  In FIG. 12B1, the pixels 410 adjacent in the direction R are pixels corresponding to different colors. At this time, as illustrated in FIG. 12B1, it is preferable that the openings 451 are provided at different positions in the conductive layer 311b so that the two pixels adjacent in the direction R are not 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.

  Alternatively, an arrangement as shown in FIG.

  If the ratio of the total area of the openings 451 to the total area of the non-openings is too large, the display using the liquid crystal element becomes dark. If the ratio of the total area of the openings 451 to the total area of the non-openings is too small, the display using the light emitting element 360 is darkened.

  In addition, when the area of the opening 451 provided in the conductive layer 311b functioning as the reflective electrode is too small, the efficiency of light that can be extracted from the light emitted from the light-emitting element 360 is reduced.

  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.

[Circuit configuration example]
FIG. 13 is a circuit diagram illustrating a configuration example of the pixel 410. In FIG. 13, two adjacent pixels 410 are shown. A difference from FIG. 10 is an example in which the wiring S1 and the wiring S2 for writing image data to the capacitor element included in the pixel circuit are provided.

  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 GD1, a wiring GD3, a wiring ANO, a wiring CSCOM, a wiring S1, and a wiring S2 are electrically connected to the pixel 410. In FIG. 13, 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. 13 shows an example in which transistors are used for the switch SW1 and the switch SW2.

  The switch SW1 has a gate connected to the wiring GD3, one of the source and the drain connected to the wiring S1, and the other of the source and the drain connected to one electrode of the capacitor C1 and one electrode of the liquid crystal element 340. Yes. The other electrode of the capacitor C1 is connected to the wiring CSCOM. The other electrode of the liquid crystal element 340 is connected to the wiring VCOM1.

  The switch SW2 has a gate connected to the wiring GD1, one of a source and a drain connected to the wiring S2, and the other of the source and the drain 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 the wiring CSCOM. In the transistor M, the other of the source and the drain 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. 13 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 GD3. 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 GD1. 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. 13 can be driven by a signal supplied to the wiring GD3 and the wiring S1 and can display using optical modulation by the liquid crystal element 340. Further, in the case where display is performed in the transmissive mode, display can be performed by driving the light-emitting element 360 to emit light by driving signals supplied to the wiring GD1 and the wiring S2. In the case of driving in both modes, the driving can be performed by signals given to the wiring GD1, the wiring GD3, the wiring S1, and the wiring S2.

  Note that although FIG. 14 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. 14A illustrates an example in which one pixel 410 includes one liquid crystal element 340 and four light-emitting elements 360 (light-emitting elements 360r, 360GD360b, and 360w).

  In FIG. 14A, in addition to the example of FIG. 13, a wiring GD4 and a wiring S3 are connected to the pixel 410.

  In the example illustrated in FIG. 14A, for example, four light-emitting elements 360 that are red (R), green (G), blue (B), and white (W) can be used. 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. 14B illustrates a configuration example of the pixel 410. 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.

[Display panel configuration example]
FIG. 15 is a schematic perspective view of a display panel 300 of one embodiment of the present invention. The display panel 300 has a structure in which a substrate 351 and a substrate 361 are attached to each other. In FIG. 15, the substrate 361 is indicated by a broken line.

  The display panel 300 includes a display portion 362, a circuit 364, a wiring 365, and the like. The substrate 351 is provided with, for example, a circuit 364, a wiring 365, a conductive layer 311b functioning as a pixel electrode, and the like. FIG. 15 shows an example in which an IC 373 and an FPC 372 are mounted on a substrate 351. Therefore, the structure illustrated in FIG. 15 can also be referred to as a display module including the display panel 300, the FPC 372, and the IC 373.

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

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

  FIG. 15 illustrates an example in which the IC 373 is provided on the substrate 351 by a COG (Chip On Glass) method or the like. As the IC 373, for example, an IC having a function as a scan line driver circuit, a wiring driver circuit, or the like can be used. Note that in the case where the display panel 300 includes a circuit that functions as a scanning line driver circuit and a wiring driver circuit, or a circuit that functions as a scanning line driver circuit or a wiring driver circuit is provided outside and the display panel 300 is driven via the FPC 372. For example, the IC 373 may be omitted. Further, the IC 373 may be mounted on the FPC 372 by a COF (Chip On Film) method or the like.

  FIG. 15 shows an enlarged view of a part of the display unit 362. In the display portion 362, conductive layers 311b included in the plurality of display elements are arranged in a matrix. The conductive layer 311b has a function of reflecting visible light, and functions as a reflective electrode of a liquid crystal element 340 described later.

  As shown in FIG. 15, the conductive layer 311b has an opening. Further, the light-emitting element 360 is provided on the substrate 351 side of the conductive layer 311b. Light from the light-emitting element 360 is emitted to the substrate 361 side through the opening of the conductive layer 311b.

  An input device 366 can be provided over the substrate 361. For example, a structure may be employed in which a sheet-like capacitive touch sensor is provided over the display portion 362. Alternatively, a touch sensor may be provided between the substrate 361 and the substrate 351. In the case where a touch sensor is provided between the substrate 361 and the substrate 351, an optical touch sensor using a photoelectric conversion element may be used in addition to the capacitive touch sensor.

[Cross-section configuration example 1]
FIG. 16 illustrates an example of a cross section of the display panel illustrated in FIG. 15 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. .

  The display panel includes an insulating layer 220 between the substrate 351 and the substrate 361. In addition, the light-emitting element 360, the transistor 201, the transistor 205, the transistor 206, the coloring layer 134, and the like are provided between the substrate 351 and the insulating layer 220. In addition, a liquid crystal element 340, a coloring layer 135, and the like are provided between the insulating layer 220 and the substrate 361. In addition, the substrate 361 and the insulating layer 220 are bonded through an adhesive layer 143, and the substrate 351 and the insulating layer 220 are bonded through an adhesive layer 142.

  The transistor 206 is electrically connected to the liquid crystal element 340, and the transistor 205 is electrically connected to the light-emitting element 360. Since both the transistor 205 and the transistor 206 are formed over the surface of the insulating layer 220 on the substrate 351 side, they can be manufactured using the same process.

  The substrate 361 is provided with a coloring layer 135, a light-blocking layer 136, an insulating layer 125, a conductive layer 313 functioning as a common electrode of the liquid crystal element 340, an alignment film 133b, an insulating layer 117, and the like. The insulating layer 117 functions as a spacer for maintaining the cell gap of the liquid crystal element 340.

  On the substrate 351 side of the insulating layer 220, insulating layers such as an insulating layer 211, an insulating layer 212, an insulating layer 213, an insulating layer 214, and an insulating layer 215 are provided. A part of the insulating layer 211 functions as a gate insulating layer of each transistor. The insulating layer 212, the insulating layer 213, and the insulating layer 214 are provided so as to cover each transistor. An insulating layer 215 is provided to cover the insulating layer 214. The insulating layer 214 and the insulating layer 215 function as a planarization layer. Note that although the case where the insulating layer covering the transistor and the like has three layers of the insulating layer 212, the insulating layer 213, and the insulating layer 214 is described here, the number of layers is not limited to this, and four or more layers may be used. There may be a layer or two layers. The insulating layer 214 functioning as a planarization layer is not necessarily provided if not necessary.

  The transistor 201, the transistor 205, and the transistor 206 include a conductive layer 221 that partially functions as a gate, a conductive layer 222 that partially functions as a source or 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.

  The liquid crystal element 340 is a reflective liquid crystal element. The liquid crystal element 340 has a stacked structure in which a conductive layer 370, a liquid crystal 312, and a conductive layer 313 are stacked. In addition, a conductive layer 311b that reflects visible light is provided in contact with the conductive layer 370 on the substrate 351 side. The conductive layer 311b has an opening 251. Further, the conductive layer 370 and the conductive layer 313 include a material that transmits visible light. An alignment film 133 a is provided between the liquid crystal 312 and the conductive layer 370, and an alignment film 133 b is provided between the liquid crystal 312 and the conductive layer 313.

  A light diffusion plate 129 and a polarizing plate 140 are disposed on the outer surface of the substrate 361. As the polarizing plate 140, a linear polarizing plate may be used, but a circular polarizing plate can 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 light diffusing plate 129 is provided to suppress external light reflection. 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 340 depending on the type of the polarizing plate.

  In the liquid crystal element 340, the conductive layer 311b has a function of reflecting visible light, and the conductive layer 313 has a function of transmitting visible light. Light incident from the substrate 361 side is polarized by the polarizing plate 140, passes through the conductive layer 313 and the liquid crystal 312, and is reflected by the conductive layer 311b. Then, the light passes through the liquid crystal 312 and the conductive layer 313 again and reaches the polarizing plate 140. At this time, alignment of liquid crystal can be controlled by a voltage applied between the conductive layer 311b and the conductive layer 313, and optical modulation of light can be controlled. That is, the intensity of light emitted through the polarizing plate 140 can be controlled. In addition, light that is not in a specific wavelength region is absorbed by the colored layer 135, so that the extracted light is, for example, red light.

  The light emitting element 360 is a bottom emission type light emitting element. The light-emitting element 360 has a stacked structure in which the conductive layer 191, the EL layer 192, and the conductive layer 193b are stacked in this order from the insulating layer 220 side. A conductive layer 193a is provided to cover the conductive layer 193b. The conductive layer 193b includes a material that reflects visible light, and the conductive layer 191 and the conductive layer 193a include a material that transmits visible light. Light emitted from the light-emitting element 360 is emitted to the substrate 361 side through the coloring layer 134, the insulating layer 220, the opening 251, the conductive layer 313, and the like.

  Here, as illustrated in FIG. 16, it is preferable that the opening 251 be provided with a conductive layer 370 that transmits visible light. Accordingly, since the liquid crystal 312 is aligned in the region overlapping with the opening 251 similarly to the other regions, it is possible to suppress the alignment failure of the liquid crystal at the boundary between these regions and the leakage of unintended light.

  An insulating layer 217 is provided over the insulating layer 216 that covers the end portion of the conductive layer 191. The insulating layer 217 has a function as a spacer for suppressing the insulating layer 220 and the substrate 351 from approaching more than necessary. In the case where the EL layer 192 and the conductive layer 193a are formed using a shielding mask (metal mask), the EL layer 192 and the conductive layer 193a may have a function of suppressing contact of the shielding mask with a formation surface. Note that the insulating layer 217 is not necessarily provided if not necessary.

  One of a source and a drain of the transistor 205 is electrically connected to the conductive layer 191 of the light-emitting element 360 through the conductive layer 224.

  One of a source and a drain of the transistor 206 is electrically connected to the conductive layer 311b through the connection portion 207. The conductive layer 311b and the conductive layer 370 are provided in contact with each other and are electrically connected. Here, the connection portion 207 is a portion that connects the conductive layers provided on both surfaces of the insulating layer 220 through openings provided in the insulating layer 220.

  A connection portion 204 is provided in a region of the substrate 351 that does not overlap with the substrate 361. The connection portion 204 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. A conductive layer obtained by processing the same conductive film as the conductive layer 370 is exposed on the upper surface of the connection portion 204. Accordingly, the connection unit 204 and the FPC 372 can be electrically connected via the connection layer 242.

  A connection portion 252 is provided in a part of the region where the adhesive layer 143 is provided. In the connection portion 252, a conductive layer obtained by processing the same conductive film as the conductive layer 370 and a part of the conductive layer 313 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 conductive layer 313 formed on the substrate 361 side through the connection portion 252.

  As the connection body 243, for example, conductive particles can be used. As the conductive particles, those obtained by coating the surface of particles such as an organic resin or silica with a metal material can be used. It is preferable to use nickel or gold as the metal material because the contact resistance can be reduced. In addition, it is preferable to use particles in which two or more kinds of metal materials are coated in layers, such as further coating nickel with gold. Further, as the connection body 243, a material that is elastically deformed or plastically deformed is preferably used. At this time, the connection body 243, which is a conductive particle, may have a shape crushed in the vertical direction as shown in FIG. By doing so, 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 problems such as connection failure can be suppressed.

  The connection body 243 is preferably disposed so as to be covered with the adhesive layer 143. For example, the connection body 243 may be dispersed in the adhesive layer 143 before curing.

  FIG. 16 illustrates an example in which the transistor 201 is provided as an example of the circuit 364.

  In FIG. 16, as an example of the transistor 201 and the transistor 205, a structure in which a semiconductor layer 231 where a channel is formed is sandwiched between two gates is applied. One gate is formed of a conductive layer 221, and the other gate is formed of a conductive layer 223 that overlaps with the semiconductor layer 231 with an insulating layer 212 interposed therebetween. With such a structure, the threshold voltage of the transistor can be controlled. At this time, 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, signal delay in each wiring can be reduced and display unevenness can be suppressed even if the number of wirings is increased when the display panel is increased in size or definition. can do.

  Note that the transistor included in the circuit 364 and the transistor included in the display portion 362 may have the same structure. In addition, the plurality of transistors included in the circuit 364 may have the same structure or may be combined with different structures. In addition, the plurality of transistors included in the display portion 362 may have the same structure or may be combined with transistors having different structures.

  At least one of the insulating layer 212 and the insulating layer 213 that covers each transistor is preferably formed using a material in which impurities such as water and hydrogen hardly diffuse. That is, the insulating layer 212 or the insulating layer 213 can function as a barrier film. With such a structure, it is possible to effectively prevent impurities from diffusing from the outside to the transistor, and a highly reliable display panel can be realized.

  On the substrate 361 side, an insulating layer 125 is provided so as to cover the coloring layer 135 and the light shielding layer 136. The insulating layer 125 may function as a planarization layer. Since the surface of the conductive layer 313 can be substantially flattened by the insulating layer 125, the alignment state of the liquid crystal 312 can be made uniform.

[Cross-section configuration example 2]
The display panel shown in FIG. 17 is an example in which a top-gate transistor is applied to each transistor in the structure shown in FIG. In this manner, by applying a top-gate transistor, parasitic capacitance can be reduced, so that a display frame frequency can be increased.

  The transistor included in the display device of one embodiment of the present invention functions as a conductive layer functioning as a gate electrode, a semiconductor layer, a conductive layer functioning as a source electrode, a conductive layer functioning as a drain electrode, and a gate insulating layer. And an insulating layer.

  Note that there is no particular limitation on the structure of the transistor. For example, a planar transistor, a staggered transistor, or an inverted staggered transistor may be used. Further, a top-gate or bottom-gate transistor structure may be employed. Alternatively, gate electrodes may be provided above and below the channel.

  There is no particular limitation on the crystallinity of a semiconductor material used for the transistor, and any of an amorphous semiconductor and a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor partially including a crystal region) is used. May be used. It is preferable to use a crystalline semiconductor because deterioration of transistor characteristics can be suppressed.

  As a semiconductor material used for the transistor, a metal oxide having an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used. Typically, an oxide semiconductor containing indium can be used.

  A transistor using an oxide semiconductor with a wider band gap and lower carrier density than silicon can hold charge accumulated in a capacitor connected in series with the transistor for a long time due to its low off-state current. Is possible.

  The semiconductor layer includes, for example, an In-M-Zn-based oxide including In, M, and M (metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium), In-M. A film represented by a series oxide, an M-Zn series oxide, or an In-Zn oxide can be used.

  In the case where the oxide semiconductor included in the semiconductor layer is an In-M-Zn-based oxide, the atomic ratio of the metal elements of the sputtering target used for forming the In-M-Zn oxide is In ≧ M, Zn It is preferable to satisfy ≧ M. As the atomic ratio of the metal elements of such a sputtering target, In: M: Zn = 1: 1: 1, In: M: Zn = 1: 1: 1.2, In: M: Zn = 3: 1: 2, In: M: Zn = 4: 2: 3, In: M: Zn = 4: 2: 4.1, In: M: Zn = 5: 1: 6, In: M: Zn = 5: 1: 7, In: M: Zn = 5: 1: 8 etc. are preferable. Note that the atomic ratio of the semiconductor layer to be formed includes a variation of plus or minus 40% of the atomic ratio of the metal element contained in the sputtering target.

  In addition, a metal oxide formed using the above materials or the like can serve as a light-transmitting conductor by controlling impurities, oxygen vacancies, and the like. Therefore, in addition to the semiconductor layer described above, a source electrode, a drain electrode, a gate electrode, and the like, which are other components of the transistor, are formed using a light-transmitting conductor, thereby forming a light-transmitting transistor. Can do. By using the light-transmitting transistor for a pixel of the display device, the display element can be transmitted or emitted, but the transistor can be transmitted, so that the aperture ratio can be improved.

  For example, as in the modification example of the cross-sectional configuration example 1 illustrated in FIG. 18, the elements included in the transistors 205 and 206 and the connection portion 207 can be formed using a light-transmitting conductor. By omitting the conductive layer 311b from the cross-sectional configuration example 1, light emitted from the light-emitting element 360 can pass through some or all of the transistors 205 and 206 and the connection portion 207. In addition, light incident from the substrate 361 side and transmitted through the liquid crystal 312 can be reflected by the conductive layer 311b. Note that in order to improve the reliability of the transistors 205 and 206, one or both of the conductive layer functioning as a gate electrode and the conductive layer functioning as a back gate electrode are formed using a layer having no light-transmitting property, such as a metal. May be.

  Silicon may be used for the semiconductor in which the channel of the transistor is formed. Although amorphous silicon may be used as silicon, it is particularly preferable to use silicon having crystallinity. For example, microcrystalline silicon, polycrystalline silicon, single crystal silicon, or the like is preferably used. In particular, polycrystalline silicon can be formed at a lower temperature than single crystal silicon, and has higher field effect mobility and higher reliability than amorphous silicon.

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

(Embodiment 6)
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, in the case where a metal oxide is used for a semiconductor layer of a transistor, the metal oxide may be referred to as an oxide semiconductor. In other words, when a metal oxide has at least one of an amplifying function, a rectifying function, and a switching function, the metal oxide can be referred to as a metal oxide semiconductor, or OS for short. 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 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.

  Further, in this specification and the like, there are cases where they are described as CAAC (c-axis aligned crystal) and CAC (Cloud-aligned Composite). Note that CAAC represents an example of a crystal structure, and CAC represents an example of a function or a material structure.

  In this specification and the like, a CAC-OS or a CAC-metal oxide has a conductive function in part of a material and an insulating function in part of the material, and the whole material is a semiconductor. It has the function of. Note that in the case where a CAC-OS or a CAC-metal oxide is used for a semiconductor layer of a transistor, the conductive function is a function of flowing electrons (or holes) serving as carriers, and the insulating function is an electron serving as carriers. It is a function that does not flow. By performing the conductive function and the insulating function in a complementary manner, a switching function (a function for turning on / off) can be given to the CAC-OS or the CAC-metal oxide. In CAC-OS or CAC-metal oxide, the functions of both can be maximized by separating the functions.

  Moreover, CAC-OS or CAC-metal oxide is comprised by the component which has a different band gap. For example, CAC-OS or CAC-metal oxide includes a component having a wide gap caused by an insulating region and a component having a narrow gap caused by a conductive region. In the case of the configuration, when the carrier flows, the carrier mainly flows in the component having the narrow gap. In addition, the component having a narrow gap acts in a complementary manner to the component having a wide gap, and the carrier flows through the component having the wide gap in conjunction with the component having the narrow gap. Therefore, when the CAC-OS or the CAC-metal oxide is used for a channel region of a transistor, high current driving capability, that is, high on-state current and high field-effect mobility can be obtained in the on-state of the transistor.

  That is, CAC-OS or CAC-metal oxide can also be called a matrix composite material or a metal matrix composite material.

<Configuration of CAC-OS>
A structure of a CAC-OS that can be used for the transistor disclosed in one embodiment of the present invention is described below.

  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 1 nm to 2 nm, or the vicinity thereof. Note that in the following, in an oxide semiconductor, one or more metal elements are unevenly distributed, and a region including the metal element has a size of 0.5 nm to 10 nm, preferably 1 nm to 2 nm, or the vicinity thereof. The state mixed with is also referred to as mosaic or patch.

  Note that the oxide semiconductor preferably contains at least indium. In particular, it is preferable to contain indium and zinc. In addition, aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. One kind selected from the above or a plurality of kinds may be included.

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 configured uniformly distributed in the film (hereinafter, cloud Also referred to.) A.

That, CAC-OS includes a region _{GaO X3} is the main _component, In _{X2 Zn} Y2 _{O Z2,} or _{InO X1} there is a region which is a main component, 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 sometimes refers 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 region that is observed in the form of nanoparticles mainly composed of Ga in a material structure including In, Ga, Zn, and O, and nanoparticles that are partially composed mainly of In. The region observed in a shape is a configuration in which the regions are randomly dispersed in a mosaic shape. 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, In _{X2 Zn} Y2 _{O Z2,} or the region _{InO X1} is the main component, it may clear boundary can not be observed.

  Instead of gallium, selected from aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc. In the case where one or more types are included, the CAC-OS includes a region observed in a part of a nanoparticle mainly including the metal element and a nano part mainly including In. The region observed in the form of particles refers to a configuration in which each region is randomly dispersed in a mosaic shape.

  The CAC-OS can be formed by a sputtering method, for example, without heating the substrate. In the case where a CAC-OS is formed by a sputtering method, any one or more selected from an inert gas (typically argon), an oxygen gas, and a nitrogen gas may be used as a deposition gas. Good. Further, the flow rate ratio of the oxygen gas to the total flow rate of the deposition gas during film formation is preferably as low as possible. For example, the flow rate ratio of the oxygen gas is 0% to less than 30%, preferably 0% to 10%. .

  The CAC-OS is characterized in that no clear peak is observed when measured using a θ / 2θ scan by an out-of-plane method, which is one of X-ray diffraction (XRD) measurement methods. Have That is, it can be seen from X-ray diffraction that no orientation in the ab plane direction and c-axis direction of the measurement region is observed.

  In addition, in the CAC-OS, an electron diffraction pattern obtained by irradiating an electron beam with a probe diameter of 1 nm (also referred to as a nanobeam electron beam) has a ring-like region having a high luminance and a plurality of bright regions in the ring region. A point is observed. Therefore, it can be seen from the electron beam diffraction pattern that the crystal structure of the CAC-OS has an nc (nano-crystal) structure having no orientation in the planar direction and the cross-sectional direction.

Further, for example, in a CAC-OS in an In—Ga—Zn oxide, a region in which GaO _X3 is a main component is obtained by EDX mapping obtained by using energy dispersive X-ray spectroscopy (EDX). It can be confirmed that a region in which In _X2 Zn _Y2 O _Z2 or InO _X1 is a main component is unevenly distributed and mixed.

The CAC-OS has a structure different from that of the IGZO compound in which the metal element is uniformly distributed, and has a property different from that 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 a region which is a main component, by carriers flow, expressed the conductivity of the oxide semiconductor. Therefore, 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, In _{X2 Zn} Y2 _{O Z2,} or _{InO X1} is compared to region which is a main component, has a high area insulation. 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.

Accordingly, when CAC-OS is used for a semiconductor element, high insulation is achieved by the complementary action of the insulating properties caused by GaO _{X3 and the} like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1. 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.

(Embodiment 7)
In this embodiment, portable electronic devices to which the semiconductor device of one embodiment of the present invention can be applied are described.

  19A and 19B illustrate an example of the portable information terminal 800. FIG. The portable information terminal 800 includes a housing 801, a housing 802, a display portion 803, a display portion 804, a hinge portion 805, and the like.

  The housing 801 and the housing 802 are connected by a hinge portion 805. The portable information terminal 800 can open the housing 801 and the housing 802 as illustrated in FIG. 19B from the folded state as illustrated in FIG.

  For example, document information can be displayed on the display portion 803 and the display portion 804 and can be used as an electronic book terminal. In addition, still images and moving images can be displayed on the display portion 803 and the display portion 804.

  Thus, since the portable information terminal 800 can be folded when being carried, it is excellent in versatility.

  Note that the housing 801 and the housing 802 may include a power button, an operation button, an external connection port, a speaker, a microphone, and the like.

  FIG. 19C illustrates an example of a portable information terminal. A portable information terminal 810 illustrated in FIG. 19C includes a housing 811, a display portion 812, operation buttons 813, an external connection port 814, a speaker 815, a microphone 816, a camera 817, and the like.

  The portable information terminal 810 includes a touch sensor in the display unit 812. Any operation such as making a call or inputting characters can be performed by touching the display portion 812 with a finger or a stylus.

  Further, the operation of the operation button 813 can switch the power ON / OFF operation and the type of image displayed on the display unit 812. For example, the mail creation screen can be switched to the main menu screen.

  Further, by providing a detection device such as a gyro sensor or an acceleration sensor inside the portable information terminal 810, the orientation (portrait or landscape) of the portable information terminal 810 is determined, and the screen display orientation of the display unit 812 is changed. It can be switched automatically. The screen display orientation can also be switched by touching the display portion 812, operating the operation buttons 813, or inputting voice using the microphone 816.

  The portable information terminal 810 has one or a plurality of functions selected from, for example, a telephone, a notebook, an information browsing device, or the like. Specifically, it can be used as a smartphone. The portable information terminal 810 can execute various applications such as mobile phone, electronic mail, text browsing and creation, music playback, video playback, Internet communication, and games.

  FIG. 19D illustrates an example of a camera. The camera 820 includes a housing 821, a display portion 822, operation buttons 823, a shutter button 824, and the like. A removable lens 826 is attached to the camera 820.

  Here, the camera 820 is configured such that the lens 826 can be removed from the housing 821 and replaced, but the lens 826 and the housing may be integrated.

  The camera 820 can capture a still image or a moving image by pressing the shutter button 824. In addition, the display portion 822 has a function as a touch panel and can capture an image by touching the display portion 822.

  The camera 820 can be separately attached with a strobe device, a viewfinder, and the like. Alternatively, these may be incorporated in the housing 821.

  When the semiconductor device of the present invention is used for the portable electronic device of this embodiment, when the user uses the electronic device, the proximity sensor is activated, so that display or non-display can be easily switched. . Furthermore, the electronic device can reduce power consumption. Note that at least part of this embodiment can be implemented in combination with any of the other embodiments described in this specification as appropriate.

C1 capacitive element C2 capacitive element Ctl1 control signal GD1 wiring GD2 wiring GD3 wiring GD4 wiring ND1 node ND2 node S1 wiring S2 wiring S3 wiring SW1 switch SW2 switch VCOM1 wiring VCOM2 wiring 10 switch 10a terminal 10b terminal 10c terminal 10d terminal 11 transistor 12 transistor 13 Capacitor 14 Transistor 15 Transistor 16 Capacitor 20 Display area 70 Display area 75 Pixel unit 76 Pixel 76B Display element 76G Display element 76R Display element 77 Pixel 77B Display element 77G Display element 77R Display element 117 Insulating layer 125 Insulating layer 129 Light diffusion plate 133a Alignment film 133b Alignment film 134 Colored layer 135 Colored layer 136 Light shielding layer 140 Polarizing plate 142 Adhesive layer 143 Adhesive layer 191 Conductive layer 192 EL layer 193 Conductive layer 193b Conductive layer 201 Transistor 204 connecting portion 205 Transistor 206 transistor 207 connecting portion 211 Insulating layer 212 Insulating layer 213 Insulating layer 214 Insulating layer 215 Insulating layer 216 Insulating layer 217 Insulating layer 220 Insulating layer 221 Conducting layer 222 Conducting layer 223 Conducting layer 224 conductive layer 231 semiconductor layer 242 connection layer 243 connection body 251 opening 252 connection portion 300 display panel 311 electrode 311b conductive layer 312 liquid crystal 313 conductive layer 340 liquid crystal element 351 substrate 360 light emitting element 360b light emitting element 360g light emitting element 360r light emitting element 360w light emitting element 361 Substrate 362 Display unit 364 Circuit 365 Wiring 366 Input device 370 Conductive layer 372 FPC
373 IC
400 Display device 410 Pixel 451 Opening 700 Electronic device 700a Case 701 Processor 702 Storage device 703 Communication module 704 Speaker 705 Microphone 706 Proximity sensor 706a Proximity sensor 706b Proximity sensor 707 Display sensor 708a Display device 708b Touch panel 708c Display controller 708d Frame Memory 708e Display panel 708f Display panel 709 Output device 710 Input device 710a Button switch 711 Battery 720 Pixel circuit 720a Display element 720b Display element 800 Portable information terminal 801 Case 802 Case 803 Display portion 804 Display portion 805 Hinge portion 810 Portable information terminal 811 Housing 812 Display unit 813 Operation button 814 External connection port 815 Speaker 816 817 Camera 820 Camera 821 Housing 822 Display unit 823 Operation button 824 Shutter button 826 Lens 900 Pixel 900s Shading area 900t Transmission area 901 Driving circuit section 902 Wiring 904 Wiring 906 Wiring 910 Transistor 911 Transistor 912 Transistor 913 Capacitance element 916B Light emitting area 916G Light emitting region 916R Light emitting region 930EL Light emitting element

Claims (7)

A display device, a sensor, a switch, and a first wiring;
The display device includes a plurality of pixel circuits, a scanning line, a signal line, a second wiring, and a first node.
The pixel circuit includes a first transistor, a second transistor, a capacitor, a display element, and a second node.
The switch is electrically connected to the first wiring, the second wiring, the first node, and the sensor;
A gate of the first transistor is electrically connected to the scan line;
One of the drain and the source of the first transistor is electrically connected to the signal line,
The other of the drain and the source of the first transistor is electrically connected to one of the electrodes of the capacitor and the gate of the second transistor;
One of a drain and a source of the second transistor is electrically connected to the first node;
The other of the drain and the source of the second transistor is connected to one electrode of the display element,
The display device, wherein the other electrode of the capacitor is electrically connected to the second wiring. In claim 1,
The sensor has a function of receiving a first signal;
The sensor has a function of activating a function of detecting a detection body by the first signal,
The sensor has a function of giving a second signal to the switch when an approaching detection body is detected,
The display device has a function of connecting either the first wiring or the second wiring to the first node by the second signal. In claim 1 or claim 2,
A voltage that contributes to light emission of the light emitting element is applied to the first wiring,
The display device, wherein a voltage that does not contribute to light emission of the light emitting element is applied to the second wiring. In any one of Claims 1 thru | or 3,
The display device, wherein the first display element is a light emitting element.   5. The display device according to claim 1, comprising the first transistor and the second transistor, wherein the first transistor and the second transistor include a metal oxide in a semiconductor layer. In claim 5,
The display device, wherein the transistor including a metal oxide in a semiconductor layer includes a back gate. A display device according to any one of claims 1 to 6;
Speakers,
And an electronic device having a microphone.

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