JP2018028589A - Display device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device that can quickly perform display having a plurality of images synthesized.SOLUTION: The display device comprises a drive circuit and a pixel unit, the drive circuit has a first circuit, the pixel unit has a first pixel and a second pixel, the first circuit has a function that determines gradation of image data input, the first circuit has the function that can input and output a first digital data and a second digital data, the first circuit has the function that, when the gradation of the second digital data is determined as a first value, outputs the first digital data, and the first circuit has the function that, when the gradation of the second digital data is determined as a second value, outputs the second digital data.SELECTED DRAWING: Figure 1

Description

The present invention 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 light-emitting device, a display device, an electronic device, a lighting device, a driving method thereof, or a manufacturing method thereof. In particular, the present invention relates to a display device (display panel) capable of displaying on a curved surface. Alternatively, the present invention relates to an electronic device, a light-emitting device, a lighting device, or a manufacturing method thereof including a display device capable of displaying on a curved surface.

Note that in this specification and the like, a semiconductor device refers to any device that can function by utilizing semiconductor characteristics. A transistor, a semiconductor circuit, an arithmetic device, a memory device, or the like is one embodiment of a semiconductor device. In addition, the imaging light emitting device, the display device, the electronic device, the lighting device, and the electronic device may include a semiconductor device.

In recent years, electronic devices such as smartphones and tablet terminals have become widespread, and opportunities for using information communication outdoors have increased. In the field of display devices included in information terminals, development of low power consumption technology capable of long-time operation with a limited battery capacity is being competed. For example, Patent Document 1 discloses a liquid crystal display device with low power consumption that holds an image signal for a long time by using a transistor having an oxide semiconductor with low off-state current for a pixel.

JP 2011-141522 A

In an electronic device including the display device as described above, when a plurality of images are combined and displayed, a technique called augmented reality (AR) that adds and displays information on a part of a subject is used. Is done.

In such a case, data processing for combining the original image and the image to be added is necessary. The data processing is performed by the data processing circuit, and the processed data is input to the driving circuit of the display device and displayed on the display unit. The data processing requires time corresponding to the amount of data, but it is desired to perform the data processing at high speed in order to obtain consistency with the actual data.

On the other hand, since most electronic devices are driven by a battery, low power consumption is required even when the above data processing is performed.

Therefore, an object of one embodiment of the present invention is to provide a display device that can display at a high speed by combining a plurality of images. Another object is to provide a display device including a driver circuit having a function of combining image data. Another object is to provide a display device that performs display with a display element suitable for display contents for each display area. Another object is to provide a display device with low power consumption. Another object is to provide a highly recognizable display device. Another object is to provide a novel display device. Another object is to provide an electronic device including the display device. Another object is to provide a new electronic device.

Note that the description of these problems does not disturb the existence of other problems. In one embodiment of the present invention, it is not necessary to solve all of these problems. Problems other than those described above are naturally clarified from the description of the specification and the like, and problems other than the above can be extracted from the description of the specification and the like.

One embodiment of the present invention includes a display device having a function of emitting visible light, a display device having a function of reflecting visible light, a display device having a function of emitting visible light, and a function of reflecting visible light, and any of the above The present invention relates to an electronic device having a display device.

One embodiment of the present invention is a display device including a driver circuit and a pixel unit, the driver circuit includes a first circuit, and the pixel unit includes a first pixel, a second pixel, The first circuit has a function of determining the gradation of the input image data, and the first circuit has a function of inputting / outputting the first digital data and the second digital data. And the first circuit has a function of outputting the first digital data when the gradation of the second digital data is determined to be the first value. When the gradation of the second digital data is determined to be the second value, it has a function of outputting the second digital data, and the drive circuit converts the first digital data to the first analog data And the drive circuit outputs the second digital data to the second pixel. A display device having a function of outputting the second pixel is converted into log data.

Another embodiment of the present invention is a display device including a driver circuit and a pixel unit. The driver circuit includes a first circuit. The pixel unit includes a first pixel and a second pixel. The first circuit has a function of determining the gradation of the input image data, and the first circuit has the first digital data, the second digital data, and the first 3 and 4th digital data can be input and output, and when the first circuit determines that the gradation of the second digital data is the first value, The first digital data and the third digital data are output. When the first circuit determines that the gray level of the second digital data is the second value, the second digital data And the function of outputting the fourth digital data, and the driving circuit has the first circuit When it is determined that the gray level of the second digital data is the first value, the first digital data is converted into the first analog data and output to the first pixel, and the third digital data is converted into the first digital data. 3 having a function of converting the analog data into the second pixel and outputting the analog data to the second pixel. When the driving circuit determines that the gradation of the second digital data is the second value, Display device having function of converting second digital data to second analog data and outputting to second pixel, and converting fourth digital data to fourth analog data and outputting to first pixel It is.

Another embodiment of the present invention is a display device including a driver circuit and a pixel unit, the driver circuit including a first circuit and a second circuit, and the pixel unit including the first circuit The first circuit has a function of determining the gradation of the input image data, the first circuit includes the first digital data, the second pixel, and the second pixel. Digital data can be input / output, and the second circuit can input / output first analog data, second analog data, third analog data, and fourth analog data. The first circuit has a function of outputting the first digital data when the gradation of the second digital data is determined to be the first value, and the first circuit Is the second digital data when the gradation of the second digital data is determined to be the second value. And the driving circuit outputs the first digital data to the first analog when the first circuit determines that the gradation of the second digital data is the first value. The driver circuit has a function of converting to data and inputting to the second circuit, and when the first circuit determines that the gradation of the second digital data is the second value, the second circuit The driver circuit has a function of converting digital data into second analog data and inputting the second analog data to the second circuit, and the driving circuit determines that the first circuit has the first digital signal gradation as the first value. The second circuit has a function of outputting the first analog data to the first pixel and outputting the third analog data to the second pixel. When it is determined that the gradation of the second digital data is the second value, the second circuit has the second analog Outputs over data to the second pixel, a display device having a function of outputting a fourth analog data to the first pixel.

The first pixel can include a second display element having a function of emitting visible light, and the second pixel can include a first display element having a function of reflecting visible light.

The first value can be a value indicating that the first value is not a significant image, and the second value can be a value indicating that the image is a significant image.

In addition, the first value can be smaller than a threshold value indicating that the image is significant, and the second value can be equal to or greater than the threshold value.

The first pixel and the second pixel preferably include a transistor including a metal oxide in a semiconductor layer where a channel is formed.

In this specification, a module in which a connector, for example, an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached to a display device (display panel), a module in which a printed wiring board is provided at the end of TCP, Alternatively, a module in which an IC (Integrated Circuit) is directly mounted on a substrate over which a display element is formed by a COG (Chip On Glass) method may include a display device.

By using one embodiment of the present invention, a display device that can display at a high speed a composite of a plurality of images can be provided. Alternatively, a display device including a driver circuit having a function of combining image data can be provided. Alternatively, it is possible to provide a display device that performs display with a display element suitable for display content for each display area. Alternatively, a display device with low power consumption can be provided. Alternatively, a highly recognizable display device can be provided. Alternatively, a novel display device can be provided. Alternatively, an electronic device including the display device can be provided. Alternatively, a novel electronic device can be provided.

Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. It should be noted that the effects other than these are naturally obvious from the description of the specification, drawings, claims, etc., and it is possible to extract the other effects from the descriptions of the specification, drawings, claims, etc. It is.

FIG. 11 is a block diagram illustrating a display device. The figure explaining the specific example of a display. The figure explaining the specific example of a display. FIG. 9 is a block diagram illustrating a driver circuit. The circuit diagram explaining an example of a circuit block. FIG. 9 is a block diagram illustrating a driver circuit. The circuit diagram explaining an example of a circuit block. The circuit diagram explaining an example of a circuit block. 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. 6 is a flowchart for explaining operations of a driving circuit and a pixel unit. 10A and 10B each illustrate an electronic device.

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

Note that in structures of the invention described below, the same portions or portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated. In addition, in the case where the same function is indicated, the hatch pattern is the same, and there is a case where no reference numeral is given.

Note that in each drawing described in this specification, the size, the layer thickness, or the region of each component is exaggerated for simplicity in some cases. Therefore, it is not necessarily limited to the scale.

In the present specification and the like, ordinal numbers such as “first” and “second” are used for avoiding confusion between components, and are not limited numerically.

(Embodiment 1)
In this embodiment, a display device of one embodiment of the present invention will be described with reference to drawings.

The display device of one embodiment of the present invention includes a driver circuit having a determination circuit and two different display elements in one pixel unit, and can display at a high speed by combining a plurality of images.

FIG. 1 is a block diagram illustrating a display device of one embodiment of the present invention. The display device 10 illustrated in FIG. 1 includes a drive circuit 20, a drive circuit 31, a drive circuit 32, and a pixel array 40.

The driver circuit 20 can function as a source driver, and includes a circuit 21 and a circuit 22. In addition, each block and wiring of the drive circuit 20 are illustrated in a simplified manner, and details will be described later. The drive circuits 31 and 32 can function as gate drivers for driving different pixels.

The pixel array 40 includes pixel units 45 arranged in a matrix of m rows and n columns (m and n are natural numbers of 2 or more). The pixel unit 45 includes a pixel 46 and a pixel 47.

The drive circuit 20 is electrically connected to each of the pixel 46 and the pixel 47 through each source line. The drive circuit 31 is electrically connected to the pixel 46 through the first gate line. The drive circuit 32 is electrically connected to the pixel 47 through the second gate line.

The circuit 21 includes a sequential circuit and is electrically connected to the circuit 22. The circuit 22 is electrically connected to the pixel 46 and the pixel 47, and can compare and determine the gradation of image data input to one pixel. In addition, the circuit 22 has a function of switching so that display is performed on one of the pixels 46 and 47 according to the determination result.

Although details will be described later, the pixel 46 includes a first display element, and the pixel 47 includes a second display element. For example, a light-emitting element can be used as the first display element. As the second display element, for example, a reflective liquid crystal element can be used. The light-emitting element can perform display with high visibility, and the reflective liquid crystal element can operate with low power consumption. Note that the pixel 46 may include the second display element and the pixel 47 may include the first display element.

Here, operations of the drive circuit 20 and the pixel unit 45 will be described with reference to a flowchart shown in FIG.

First, a column is selected by the circuit 21 (S1), and DATA1 and DATA2 corresponding to the column are input (S2). Note that DATA1 is input to the column to which the pixel 46 is connected, and DATA2 is input to the column to which the pixel 47 is connected.

Here, DATA1 and DATA2 are digital data, and DATA1 is data of an original image such as a background image. DATA2 is image data to be added to the original image.

The circuit 22 determines the gradation of DATA2, and determines whether or not the gradation is greater than or equal to the first value (S3). The first value is a threshold value indicating significant data. That is, when the gradation of DATA2 is smaller than the first value, it is determined that “there is no image data to be added to the original image”. If the gradation of DATA2 is equal to or higher than the first value, it is determined that “there is image data to be added to the original image”.

When the gradation of DATA2 is smaller than the first value, the drive circuit 20 converts DATA1 into DATA1 'that is analog data, and outputs DATA1' to the pixel 46. Further, as DATA2 ', data corresponding to black display is output to the pixel 47 (S4).

Further, when the gradation of DATA2 is equal to or higher than the first value, the drive circuit 20 converts DATA2 into DATA2 'that is analog data, and outputs DATA2' to the pixel 47. Further, as DATA1 ', data corresponding to black display is output to the pixel 46 (S5).

By performing the above operation on all the columns, it is possible to display the combined image at high speed.

Next, a specific example of display will be described. FIG. 2 is a diagram for explaining a case where image data is combined and displayed on the display device 10b as a conventional example. The display device 10b includes a drive circuit 20b (source driver) and a drive circuit 31b (gate driver) having a basic function of supplying data to a selected pixel, and a pixel array 40b including pixels having one type of display element. Have.

Here, a description will be given by taking as an example a diagram that means an image of a building group as the original image (DATA1) and a service facility as the image to be added (DATA2).

DATA1 is an image captured by the user with an electronic device, and DATA2 is information desired by the user acquired using a GPS function, a communication function, a shape recognition function, and the like of the electronic device.

In the conventional example, after acquiring DATA1 and DATA2, image data (DATA3) obtained by combining DATA1 and DATA2 is generated using the data processing circuit 50. Then, DATA3 is supplied to the pixel array 40b via the drive circuit 20b, and display is performed by the pixel array 40b.

That is, it takes time to newly generate image data (DATA3). Therefore, in order to obtain consistency with reality, the data processing must be performed at high speed. However, power consumption increases for high-speed data processing. Further, if the amount of data processing is enormous, it takes time to process, and a large delay occurs in the display timing.

FIG. 3 illustrates a case where image data is combined and displayed on the display device of one embodiment of the present invention. Note that DATA1 and DATA2 are the same as those in FIG.

The driver circuit 20 included in the display device of one embodiment of the present invention includes the pixel 46 that displays DATA1 and the pixel 47 that displays DATA2, and can display both pixels in combination. Therefore, DATA1 and DATA2 can be directly input to the drive circuit 20, and display can be performed at high speed. In addition, since the data processing circuit 50 is not necessary, power for generating DATA3 is also unnecessary.

In addition, the circuit 22 included in the driving circuit 20 only needs to be able to operate with a cycle time of a relatively low frequency used for image display. Therefore, even a display device with a large number of pixels (number of columns) can be processed sufficiently. .

In addition, in the image to be added (DATA2), it is preferable to set, for example, a gradation of black display or a gradation in the vicinity thereof other than a significant figure region. As described above, the circuit 22 determines the gradation of DATA2, and determines whether or not it is equal to or higher than the first value. Therefore, the circuit 22 can determine the presence / absence of a significant figure when the gradation of black display or the gradation in the vicinity thereof is set to the first value. At this time, it is preferable that the significant image area of the image to be added (DATA2) does not include an image having a gradation equal to or lower than the first value. In this way, characters and figures that can be recognized as black can be recognized as significant data in DATA2.

Note that the display device according to one embodiment of the present invention can display not only the pixel 46 and the pixel 47 as described above but also the pixel 46 alone or the pixel 47 alone.

As an example of performing display using only the pixels 46, all-black display DATA 2 configured with gradations smaller than the first value may be input to the drive circuit 20. In the circuit 22, it is determined that there is no data that constitutes a region of the significant figure in DATA 2, and only DATA 1 is output from the drive circuit 20. That is, display is performed only with the pixels 46.

As an example in which display is performed using only the pixels 47, DATA2 may be configured with gradations equal to or higher than the first value and input to the drive circuit 20. In the circuit 22, DATA2 is all determined to be a significant region of the figure, and only the DATA2 is output from the drive circuit 20. That is, display is performed only with the pixels 47.

Note that if the operation of the circuit 22 is turned off and DATA2 is set to the same data as DATA1, a background image or the like can be displayed on both the pixel 46 and the pixel 47.

FIG. 4 is a block diagram showing a specific configuration of the drive circuit 20. The drive circuit 20 has a function of converting an M-bit (M is a natural number of 2 or more) digital signal into an analog voltage signal. The number of output terminals for outputting the voltage signal to the outside is n (n is a natural number of 2 or more).

The drive circuit 20 includes, as a circuit 21, a shift register circuit (SR), a first latch circuit (LAT1), a circuit 22, a decoder circuit (DEC), a second latch circuit (LAT2), and a level shifter circuit ( LS), a DA converter circuit (R-DAC), a pass transistor logic circuit (PTL), and an amplifier circuit (AMP). Note that R-DAC, PTL, and AMP are preferably configured to be suitable for the first display element (light-emitting element) and the second display element (liquid crystal element), respectively.

A reset signal (RESET), a clock signal (CLK), and a start pulse (SP) can be input to SR. An SR selection signal and digital image data DATA1 or DATA2 are input to LAT1 subsequent to SR. In the configuration shown in FIG. 4, DATA1 is input to a column where data is output to the pixel 46, and DATA2 is input to a column where data is output to the pixel 47, but DATA2 is a column where data is output to the pixel 46. And DATA1 may be input to a column in which data is output to the pixel 47.

The circuit 22 outputs DATA1 and DATA2 from LAT1. As described above, the circuit 22 has a function of determining whether there is significant image data (DATA2) to be added to the image data (DATA1). For example, when DATA2 is black display data, it is determined that there is no additional data, and DATA1 is output to a subsequent circuit. At this time, the circuit 22 may perform an operation that does not output DATA2 to the subsequent circuit, or may output DATA2 to the subsequent circuit. Even if black display corresponding to DATA2 is performed by the pixel 47, the visibility of DATA1 displayed by the pixel 46 is not lowered.

If DATA2 is significant image data, the circuit 22 determines that there is additional data, and outputs DATA2 to a subsequent circuit. At this time, the circuit 22 forcibly outputs black display data as DATA1 to the subsequent circuit in order to prevent the display of DATA1 and DATA2 from overlapping. Alternatively, a function of outputting a voltage signal corresponding to black display data may be added to the subsequent AMP.

The image data output from the circuit 22 is input to the LAT 2 via DEC. A synchronization signal (LS) is input to LAT2, and the outputs of LAT2 of all columns can be synchronized and input to the subsequent level shifter (LS). Note that the synchronization signal (LS) is not limited to one system, and the block-unit LAT 2 may be synchronized with a plurality of systems. By doing in this way, the change of the power supply voltage by a through-current etc. can be suppressed and the malfunction of the drive circuit 20 can be prevented.

Image data output from the level shifter (LS) is input to the PTL. DATA1 and DATA2 are converted into DATA1 'and DATA2' which are analog voltage signals by PTL and R_DAC for light emitting element or R_DAC for liquid crystal element, and output to output line SOUT via each AMP. Here, DATA 1 ′ is output to the pixel 46, and DATA 2 ′ is output to the pixel 47.

By executing such an operation, the drive circuit 20 can perform a process of combining the image data and the additional data. Since image processing in an external circuit is unnecessary, the input timing to the source driver can be advanced, and the composite image can be displayed on the display at high speed.

FIG. 5A illustrates an example of the circuit 22. The data input to the circuit 22 is digital data. When the comparison target digital data is A and B, the comparison is performed by processing AB. If the result is negative, A <B, and if positive, A ≧ B. In digital data, since it is possible to set A−B = A + Bb + 1 (b is an inverted signal), the adder 25 can be used.

For example, the adder 25 can be composed of two XOR circuits, two AND circuits, and one OR circuit as shown in FIG. The carry data from the lower digit is input to the Cin terminal, and the carry data of A + B + Cin is output to the Cout terminal. When the digital data is 4 bits, 4 bits of digital data can be added by using the same four adders 25 as the number of bits. The circuit has a configuration in which an inverter for inverting data is added to one of the input terminals of the adder 25.

FIG. 5A shows a block A shown in FIG. The circuit 22 may include adders 25a to 25d, analog switches 26a to 26f, inverters 27a to 27g, and a NAND circuit 28.

In the following description, DATA1 is assumed to be a 3-bit gradation digital signal, and DATA2 is assumed to be a 3-bit gradation and a 4-bit digital signal having the most significant bit as a code signal.

DATA1 [2: 0] is a signal output from the LAT1 of the column to which SR001 is connected, and the signal is output to the DEC of the column to which SR001 is connected. DATA2 [2: 0] is a signal output from LAT1 subsequent to SR002, and this signal is output to the DEC in the column to which SR002 is connected.

DATA2_ [3], DATA2_ [2], DATA2_ [1], and DATA2_ [0] are input to one terminal of each of the adders 25a to 25d. Further, B_ [3], B_ [2], B_ [1], and B_ [0] are input to the other terminals of the adders 25a to 25d through the inverters 27a to 27d, respectively. Note that although Y [3: 0] and Cout are output from the adders 25a to 25d, only Y [3] is used here, and Cout and Y [2: 0] are not used. Note that more detailed control may be performed using Cout and Y [2: 0].

Here, DATA2_ [3] is a code bit and is data added to the input data DATA2 [2: 0] as “0” inside the circuit. DATA2_ [2], DATA2_ [1], and DATA2_ [0] are gradation data. B_ [3], B_ [2], B_ [1], and B_ [0] separate B [3: 0], which is the threshold data corresponding to the first value, into 1-bit units. It is data.

Black display data “000” is input to the analog switches 26a and 26c. Further, DATA1 [2: 0] is input to the analog switch 26b, and DATA2 [2: 0] is input to the analog switch 26d.

Here, when Y [3] = “0”, that is, DATA2 [3: 0] ≧ B [3: 0], the analog switches 26a, 26b, 26c, 26d, 26e, and 26f are turned on, off, off, on, on, off. Therefore, black display data “000” is output from the analog switch 26a to the DEC in the first column, and DATA2 [2: 0] is output from the analog switch 26e to the DEC in the second column. That is, the pixel 46 is displayed in black, and the pixel 47 is displayed with DATA2.

When Y [3] = “1”, that is, DATA2 [3: 0] <B [3: 0], the analog switches 26a, 26b, 26c, 26d, 26e, and 26f are turned off, on, on, and off, respectively. , On, off. Therefore, DATA1 [2: 0] is output from the analog switch 26b to the DEC in the first column, and black display data “000” is output from the analog switch 26e to the DEC in the second column. That is, DATA1 is displayed on the pixel 46, and the pixel 47 is displayed in black.

The signal HEB input to the NAND circuit 28 and the inverter 27g is a signal for turning on / off a hybrid mode in which a background image or the like is displayed on both the pixel 46 and the pixel 47, and is “0”. DATA2 [2: 0] can be output from the analog switch 26f to the DEC in the second column, and display in the hybrid mode can be performed.

When the gradation is 3 bits, it is desirable that digital data input from the outside be 3 bits (absolute value) and that “0” is added to the 4 bits as a code internally. The light emitting element basically has only a positive value, and the liquid crystal element outputs a negative voltage, but the black display has the smallest (or larger) absolute value data, so it is only necessary to compare with a positive value. . In the configuration in which 4-bit data is input from the input terminal, the circuit scale of the input unit becomes large.

The above is an example of forcibly outputting black display data as DATA1 to a circuit subsequent to the circuit 22 when DATA2 display is enabled. Next, an example of changing the input signal of the AMP according to the result of the circuit 22 will be described.

FIG. 6 shows a block diagram of the drive circuit 20 for changing the input signal of the AMP according to the result of the circuit 22. The block diagram is the same as FIG. 4 except that the circuit 22 and the AMP are directly electrically connected.

FIG. 7 shows the block B shown in FIG. The circuit 22 can include an adder 25a to 25d, an inverter 27a to 27g, and a NAND circuit 28.

FIG. 8 shows a block C shown in FIG. The AMP (OLEDAMP, LCDAMP) can include analog switches 26a to 26f and operational amplifiers 28a and 28b.

Here, the inverter 27f provided in the block B can output the signal SUBE, the NAND circuit 28 can output the signal MAIN, and the inverter 27g can output the signal HE. The signal SUBE, the signal MAIN, the signal HE, and the signal HEB are appropriately input to the analog switches 26a to 26f provided in the block C via different wirings and level shifter circuits.

The analog switches 26a to 26f to be connected to the output terminals of the inverter 27f, NAND circuit 28, and inverter 27g are the same as those in FIG. Therefore, the above description can be referred to as the circuit operation.

Note that 0 V, which is an analog voltage signal, is input to the analog switches 26a and 26c. Further, DATA1 'which is an analog voltage signal is input to the analog switch 26b, and DATA2' which is an analog voltage signal is input to the analog switch 26d.

Therefore, the operational amplifier 28a to which the analog switches 26a and 26b are electrically connected can output the amplified DATA 1 'to SOUT [1]. The operational amplifier 28b to which the analog switches 26e and 26f are electrically connected can output the amplified DATA 2 'to SOUT [2]. The operational amplifiers 28a and 28b can output 0V corresponding to black display data when the output of DATA1 'or DATA2' is not selected. If 0V does not correspond to black display data, a voltage signal corresponding to black display may be used.

In this configuration, in order to input analog-converted image data to the analog switch, only one analog switch to which DATA1 and DATA2 are input is required. On the other hand, in the configuration shown in FIGS. 4 and 5 described above, since digital data is input to the analog switch, analog switches in the input portion of the image signal are required for the number of bits. Therefore, in this configuration, the number of analog switches can be reduced.

In addition, when the output of the AMP becomes 0 V, the operation of the circuit in the previous stage becomes unnecessary. For example, DEC, LAT2, LS, etc. in the same row as the AMP can be turned off to save power. Can do.

By using the display device having the above-described configuration, display in which a plurality of images are combined can be performed at high speed.

A metal oxide is preferably used for a semiconductor layer in a semiconductor device such as a pixel included in each display region described above or a transistor used in a circuit for driving the pixel. As the metal oxide, for example, a CAC-OS (Cloud Aligned Complementary-Oxide Semiconductor) described later can be used.

In particular, an oxide semiconductor having a larger band gap than silicon is preferably used. When a semiconductor material having a wider band gap and lower carrier density than silicon is used, current in an off state of the transistor can be reduced.

In addition, due to the low off-state current, the charge accumulated in the capacitor through the transistor can be held for a long time. By applying such a transistor to a pixel, the driving circuit can be stopped while maintaining the gradation of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.

A polycrystalline semiconductor may be used for a semiconductor device such as a pixel included in each display region described above or a transistor used in a circuit for driving the pixel. For example, it is preferable to use polycrystalline silicon. 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. By applying such a polycrystalline semiconductor to a pixel, the aperture ratio of the pixel can be improved. In addition, even when a large number of pixels are included, the gate driver circuit and the source driver circuit can be formed over the same substrate as the pixel, and the number of components included in the electronic device can be reduced.

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

(Embodiment 2)
In this embodiment, a display device that can be used for one embodiment of the present invention and a method for driving the display device will be described.

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 third display element that transmits visible light. Alternatively, the pixel can include a first display element and a second display element or a third 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 a 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 method, an electrowetting method, and an electronic powder 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 (Organic Light Emitting Diode), an LED (Light Emitting Diode), a QLED (Quantum-Dot Light Emitting Diode), or a semiconductor laser can be used. Alternatively, as the display element included in the second pixel, a combination of a backlight that is a light source and a transmissive liquid crystal element that controls the amount of light transmitted through the backlight may be used.

The first pixel can include a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits three colors of light, for example, red (R), green (G), and blue (B). . Similarly, the second pixel has a sub-pixel that exhibits, for example, white (W), or a sub-pixel that exhibits light of three colors, for example, 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. Further, as shown in Embodiment Mode 1, 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. Further, by using light in which reflected light and light emission are mixed, it is possible to display an image that makes it feel as if the user is looking at a painting.

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. 9 is a diagram for explaining the pixel array 40 shown in FIG. The pixel array 40 has a plurality of pixel units 45 arranged in a matrix. The pixel unit 45 includes a pixel 46 and a pixel 47.

FIG. 9 illustrates an example in which the pixel 46 and the pixel 47 have display elements corresponding to three colors of red (R), green (G), and blue (B), respectively.

The pixel 46 includes a display element 46R corresponding to red (R), a display element 46G corresponding to green (G), and a display element 46B corresponding to blue (B). Each of the display elements 46R, 46G, and 46B is a first display element that uses light from a light source.

The pixel 47 includes a display element 47R corresponding to red (R), a display element 47G corresponding to green (G), and a display element 47B corresponding to blue (B). Each of the display elements 47R, 47G, and 47B is a second display element that utilizes reflection of external light.

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

[Configuration example of pixel unit]
Subsequently, the pixel unit 45 will be described with reference to FIGS. 10 (A), 10 (B), and 10 (C). FIGS. 10A, 10 </ b> B, and 10 </ b> C are schematic diagrams illustrating a configuration example of the pixel unit 45.

The pixel 46 includes a display element 46R, a display element 46G, and a display element 46B. The display element 46R has a light source, and emits red light R2 having a luminance corresponding to the gradation value corresponding to red included in the second gradation value input to the pixel 46 to the display surface side. Similarly, the display element 46G and the display element 46B respectively emit green light G2 or blue light B2 to the display surface side.

The pixel 47 includes a display element 47R, a display element 47G, and a display element 47B. The display element 47 </ b> R reflects external light and emits red light R <b> 1 having luminance corresponding to the gradation value corresponding to red included in the first gradation value input to the pixel 47 to the display surface side. . Similarly, the display element 47G and the display element 47B respectively emit green light G1 or blue light B1 to the display surface side.

[Third mode]
FIG. 10A shows an operation in which an image is displayed by driving both the display element 47R, the display element 47G, and the display element 47B that reflect external light, and the display element 46R, the display element 46G, and the display element 46B that emit light. An example of the mode is shown. As shown in FIG. 10A, the pixel unit 45 mixes six lights of light R1, light G1, light B1, light R2, light G2, and light B2 to emit light 55 of a predetermined color. It can be emitted to the display surface side.

At this time, it is preferable to suppress the luminance of each of the display element 46R, the display element 46G, and the display element 46B. For example, when the maximum value of the luminance of light that can be emitted from each of the display element 46R, the display element 46G, and the display element 46B (also referred to as maximum luminance) is 100%, the display element 46R and the display in the third mode are displayed. It is preferable that the maximum value of the luminance of light emitted from each of the element 46G and the display element 46B is 5% to 50%, preferably 1% to 60% of the maximum luminance. As a result, it is possible to display with low power consumption, and the displayed image becomes more pictorial, and it is possible to perform display friendly to the eyes.

[First mode]
FIG. 10B illustrates an example of an operation mode in which an image is displayed by driving the display element 47R, the display element 47G, and the display element 47B that reflect external light. As shown in FIG. 10B, the pixel unit 45 does not drive the pixel 46, for example, when the illuminance of external light is sufficiently high, and does not drive the pixel 46 (light R1, light G1, and light). By mixing only B1), it is possible to emit light 55 of a predetermined color to the display surface side. Thereby, driving with extremely low power consumption can be performed.

[Second mode]
FIG. 10C illustrates an example of an operation mode in which the display element 46R, the display element 46G, and the display element 46B are driven to display an image. As shown in FIG. 10C, the pixel unit 45 does not drive the pixel 47, for example, when the illuminance of outside light is extremely small, and the light from the pixel 46 (light R2, light G2, and light B2). ) Only, it is possible to emit light 55 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.

At this time, it is preferable to increase the luminance of the display element that emits visible light, as compared with the third mode. For example, the maximum value of the luminance of light emitted from each of the display element 46R, the display element 46G, and the display element 46B in the second mode is set to 100% of the maximum luminance, or 50% or more and 100% or less, preferably 60 % Or more and 100% or less. Thereby, a vivid image can be displayed even in a place where the outside light is bright.

Here, the maximum value of the luminance of the light emitted from each of the display element 46R, the display element 46G, and the display element 46B can be replaced with a dynamic range. That is, in the third mode, the dynamic ranges of the display element 46R, the display element 46G, and the display element 46B can be set narrower than in the second mode. For example, the dynamic range of the third mode in the display element 46R, the display element 46G, or the display element 46B is set to 5% to 50%, preferably 1% to 60% of the dynamic range of the second mode. Can do.

The above is the description of the configuration example of the pixel unit 45.

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

(Embodiment 3)
Examples of display panels that can be used for the display device of one embodiment of the present invention are described below. 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. 11A 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 G1 electrically connected to the circuit GD, a plurality of wirings G2, 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.

Here, for the sake of simplicity, a configuration having one circuit GD and one circuit SD is shown, but 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. 11B1 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. 11B1, 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. 11B1, the pixels 410 adjacent in the direction R are pixels corresponding to different colors. At this time, as illustrated in FIG. 11B1, in the two pixels adjacent to the direction R, the openings 451 are preferably provided at different positions in the conductive layer 311b so as not to be arranged in a line. Accordingly, the two light-emitting elements 360 can be separated from each other, and a phenomenon (also referred to as crosstalk) in which light emitted from the light-emitting elements 360 enters the colored layer of the adjacent pixel 410 can be suppressed. In addition, since the two adjacent light emitting elements 360 can be arranged apart from each other, a display device with high definition can be realized even when the EL layer of the light emitting element 360 is separately formed using a shadow mask or the like.

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. 12 is a circuit diagram illustrating a configuration example of the pixel 410. In FIG. 12, two adjacent pixels 410 are shown.

The pixel 410 includes a switch SW1, a capacitor C1, a liquid crystal element 340, a switch SW2, a transistor M, a capacitor C2, a light emitting element 360, and the like. In addition, the pixel 410 is electrically connected to a wiring G1, a wiring G2, a wiring ANO, a wiring CSCOM, a wiring S1, and a wiring S2. In FIG. 12, 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. 12 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 G1, one source or drain connected to the wiring S1, and the other source or 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 G2, one of the source and the 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 one of the source and the drain of the transistor M and the wiring ANO. 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. 12 shows an example in which the transistor M has two gates sandwiching a semiconductor and these are connected. As a result, the current that can be passed by the transistor M can be increased.

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

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

For example, in the case of performing reflection mode display, the pixel 410 illustrated in FIG. 12 can be driven by a signal supplied to the wiring G1 and the wiring S1 and can display using optical modulation by the liquid crystal element 340. 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 with signals given to the wiring G2 and the wiring S2. In the case of driving in both modes, the driving can be performed by signals given to the wiring G1, the wiring G2, the wiring S1, and the wiring S2.

Note that although FIG. 13 illustrates an example in which one pixel 410 includes one liquid crystal element 340 and one light emitting element 360, the present invention is not limited thereto. FIG. 13A illustrates an example in which one pixel 410 includes one liquid crystal element 340 and four light-emitting elements 360 (light-emitting elements 360r, 360g, 360b, and 360w).

In FIG. 13A, in addition to the example in FIG. 12, a wiring G3 and a wiring S3 are connected to the pixel 410.

In the example illustrated in FIG. 13A, for example, light emitting elements that exhibit red (R), green (G), blue (B), and white (W) can be used as the four light emitting elements 360, respectively. As the liquid crystal element 340, a reflective liquid crystal element exhibiting white can be used. Thereby, when displaying in reflection mode, white display with high reflectance can be performed. In addition, when display is performed in the transmissive mode, display with high color rendering properties can be performed with low power.

FIG. 13B 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. 14 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. 14, 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. 14 shows an example in which an IC 373 and an FPC 372 are mounted on a substrate 351. Therefore, the structure illustrated in FIG. 14 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. 14 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 signal line 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 signal line driver circuit, or a circuit that functions as a scanning line driver circuit or a signal line driver circuit is provided outside, and the display panel 300 is driven through the FPC 372. For example, the IC 373 may not be provided in the case of inputting a signal to do so. Further, the IC 373 may be mounted on the FPC 372 by a COF (Chip On Film) method or the like.

FIG. 14 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. 14, 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.

Further, a touch sensor can be provided over the substrate 361. For example, a structure may be employed in which a sheet-like capacitive touch sensor 366 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.
[Section configuration example]
FIG. 15 illustrates an example of a cross section of the display panel illustrated in FIG. 14 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. Show. Note that the touch sensor 366 is not included.

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 131, 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 141, 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 colored layer 131, a light-blocking layer 132, an insulating layer 121, a conductive layer 113 functioning as a common electrode for 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 have a 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. It 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 311a, a liquid crystal 112, and a conductive layer 113 are stacked. In addition, a conductive layer 311b that reflects visible light is provided in contact with the conductive layer 311a on the substrate 351 side. The conductive layer 311b has an opening 251. The conductive layer 311a and the conductive layer 113 include a material that transmits visible light. In addition, an alignment film 133 a is provided between the liquid crystal 112 and the conductive layer 311 a, and an alignment film 133 b is provided between the liquid crystal 112 and the conductive layer 113. In addition, a polarizing plate 130 is provided on the outer surface of the substrate 361.

In the liquid crystal element 340, the conductive layer 311b has a function of reflecting visible light, and the conductive layer 113 has a function of transmitting visible light. Light incident from the substrate 361 side is polarized by the polarizing plate 130, passes through the conductive layer 113 and the liquid crystal 112, and is reflected by the conductive layer 311b. Then, the light passes through the liquid crystal 112 and the conductive layer 113 again and reaches the polarizing plate 130. At this time, alignment of liquid crystal can be controlled by a voltage applied between the conductive layer 311b and the conductive layer 113, and optical modulation of light can be controlled. That is, the intensity of light emitted through the polarizing plate 130 can be controlled. In addition, light that is not in a specific wavelength region is absorbed by the colored layer 131, so that the extracted light is, for example, red light.

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 113, and the like.

Here, as shown in FIG. 15, the opening 251 is preferably provided with a conductive layer 311a that transmits visible light. Accordingly, since the liquid crystal 112 is aligned in the region overlapping with the opening 251 similarly to the other regions, alignment failure of the liquid crystal occurs at the boundary portion between these regions, and unintended light leakage can be suppressed.

Here, a linear polarizing plate may be used as the polarizing plate 130 disposed on the outer surface of the substrate 361, but a circular polarizing plate may also be used. As a circularly-polarizing plate, what laminated | stacked the linearly-polarizing plate and the quarter wavelength phase difference plate, for example can be used. Thereby, external light reflection can be suppressed. In addition, a desired contrast may be realized by adjusting a cell gap, an alignment, a driving voltage, and the like of the liquid crystal element used for the liquid crystal element 340 depending on the type of the polarizing plate.

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 or the conductive layer 193a is formed using a shielding mask (metal mask), the EL layer 192 or the conductive layer 193a may function as a mask gapper for suppressing contact of the shielding mask with a formation surface. Good. 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 311a 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 311a 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 141 is provided. In the connection portion 252, a conductive layer obtained by processing the same conductive film as the conductive layer 311 a and a part of the conductive layer 113 are electrically connected to each other through 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 113 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 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, it is preferable to use a material that is elastically deformed or plastically deformed as the connection body 243. 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 141. For example, the connection body 243 may be sprayed after applying a paste or the like to be the adhesive layer 141.

FIG. 15 illustrates an example in which the transistor 201 is provided as an example of the circuit 364.

In FIG. 15, 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 increases 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, the insulating layer 121 is provided so as to cover the colored layer 131 and the light-shielding layer 132. The insulating layer 121 may function as a planarization layer. Since the surface of the conductive layer 113 can be substantially flattened by the insulating layer 121, the alignment state of the liquid crystal 112 can be made uniform.

[About each component]
Below, each component shown above is demonstrated.

〔substrate〕
A substrate having a flat surface can be used for the substrate included in the display panel. For the substrate from which light from the display element is extracted, a material that transmits the light is used. For example, materials such as glass, quartz, ceramic, sapphire, and organic resin can be used.

By using a thin substrate, the display panel can be reduced in weight and thickness. Furthermore, a flexible display panel can be realized by using a flexible substrate.

Further, since the substrate on the side from which light emission is not extracted does not have to be translucent, a metal substrate or the like can be used in addition to the above-described substrates. A metal substrate is preferable because it has high thermal conductivity and can easily conduct heat to the entire substrate, which can suppress a local temperature increase of the display panel. In order to obtain flexibility and bendability, the thickness of the metal substrate is preferably 10 μm to 200 μm, and more preferably 20 μm to 50 μm.

Although there is no limitation in particular as a material which comprises a metal substrate, For example, metals, such as aluminum, copper, nickel, or alloys, such as aluminum alloy or stainless steel, can be used suitably.

Alternatively, a substrate that has been subjected to an insulating process by oxidizing the surface of the metal substrate or forming an insulating film on the surface may be used. For example, the insulating film may be formed by using a coating method such as a spin coating method or a dip method, an electrodeposition method, a vapor deposition method, or a sputtering method, or it is left in an oxygen atmosphere or heated, or an anodic oxidation method. For example, an oxide film may be formed on the surface of the substrate.

Examples of materials having flexibility and transparency to visible light include polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resins, polyimide resins, polymethyl methacrylate resins, and polycarbonates. (PC) resin, polyethersulfone (PES) resin, polyamide resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyvinyl chloride resin, polytetrafluoroethylene (PTFE) resin, and the like. In particular, a material having a low thermal expansion coefficient is preferably used. For example, a polyamideimide resin, a polyimide resin, PET, or the like having a thermal expansion coefficient of 30 × 10 ⁻⁶ / K or less can be suitably used. Further, a substrate in which glass fiber is impregnated with an organic resin, or a substrate in which an inorganic filler is mixed with an organic resin to reduce the thermal expansion coefficient can be used. Since a substrate using such a material is light in weight, a display panel using the substrate can be lightweight.

When a fibrous body is included in the material, a high-strength fiber of an organic compound or an inorganic compound is used for the fibrous body. The high-strength fiber specifically refers to a fiber having a high tensile modulus or Young's modulus, and representative examples include polyvinyl alcohol fiber, polyester fiber, polyamide fiber, polyethylene fiber, aramid fiber, Examples include polyparaphenylene benzobisoxazole fibers, glass fibers, and carbon fibers. Examples of the glass fiber include glass fibers using E glass, S glass, D glass, Q glass, and the like. These may be used in the form of a woven fabric or a non-woven fabric, and a structure obtained by impregnating the fiber body with a resin and curing the resin may be used as a flexible substrate. When a structure made of a fibrous body and a resin is used as the flexible substrate, it is preferable because reliability against breakage due to bending or local pressing is improved.

Alternatively, glass, metal, or the like thin enough to have flexibility can be used for the substrate. Alternatively, a composite material in which glass and a resin material are bonded to each other with an adhesive layer may be used.

A hard coat layer (for example, silicon nitride, aluminum oxide) that protects the surface of the display panel from scratches, a layer of a material that can disperse the pressure (for example, aramid resin), etc. on a flexible substrate It may be laminated. In order to suppress a decrease in the lifetime of the display element due to moisture or the like, an insulating film with low water permeability may be stacked over a flexible substrate. For example, an inorganic insulating material such as silicon nitride, silicon oxynitride, silicon nitride oxide, aluminum oxide, or aluminum nitride can be used.

The substrate can be used by stacking a plurality of layers. In particular, when the glass layer is used, the barrier property against water and oxygen can be improved and a highly reliable display panel can be obtained.

[Transistor]
The transistor includes a conductive layer that functions as a gate electrode, a semiconductor layer, a conductive layer that functions as a source electrode, a conductive layer that functions as a drain electrode, and an insulating layer that functions as a gate insulating layer. The above shows the case where a bottom-gate transistor is applied.

Note that there is no particular limitation on the structure of the transistor included in the display device of one embodiment of the present invention. 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 the semiconductor material used for the transistor, and either an amorphous semiconductor or 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. A typical example is an oxide semiconductor containing indium. For example, a CAC-OS described later 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 is represented by an In-M-Zn-based oxide containing indium, zinc, and M (metal such as aluminum, titanium, gallium, germanium, yttrium, zirconium, lanthanum, cerium, tin, neodymium, or hafnium). It can be a membrane.

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.

The bottom-gate transistor described in this embodiment is preferable because the number of manufacturing steps can be reduced. In addition, by using an oxide semiconductor at this time, the wiring under the semiconductor layer can be formed at a temperature lower than that of polycrystalline silicon, and a material having low heat resistance can be used as an electrode material and a substrate material. Can widen the choice of materials. For example, a glass substrate having an extremely large area can be suitably used.

As the semiconductor layer, an oxide semiconductor film with low carrier density is used. For example, the semiconductor layer has a carrier density of 1 × 10 ¹⁷ / cm ³ or less, preferably 1 × 10 ¹⁵ / cm ³ or less, more preferably 1 × 10 ¹³ / cm ³ or less, more preferably 1 × 10 ¹¹ / cm 3. ³ or less, more preferably less than 1 × 10 ¹⁰ / cm ³ , and an oxide semiconductor having a carrier density of 1 × 10 ⁻⁹ / cm ³ or more can be used. Such an oxide semiconductor is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Accordingly, it can be said that the oxide semiconductor has stable characteristics because the impurity concentration is low and the density of defect states is low.

Note that the composition is not limited thereto, and a transistor having an appropriate composition may be used depending on required semiconductor characteristics and electrical characteristics (such as field-effect mobility and threshold voltage) of the transistor. In addition, in order to obtain the required semiconductor characteristics of the transistor, it is preferable that the semiconductor layer have appropriate carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, and the like. .

If an oxide semiconductor included in the semiconductor layer contains silicon or carbon which is one of Group 14 elements, oxygen vacancies increase in the semiconductor layer and the semiconductor layer becomes n-type. Therefore, the concentration of silicon or carbon in the semiconductor layer (concentration obtained by secondary ion mass spectrometry) is 2 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁷ atoms / cm ³ or less.

Further, when alkali metal and alkaline earth metal are combined with an oxide semiconductor, carriers may be generated, which may increase off-state current of the transistor. Therefore, the concentration of alkali metal or alkaline earth metal obtained by secondary ion mass spectrometry in the semiconductor layer is set to 1 × 10 ¹⁸ atoms / cm ³ or less, preferably 2 × 10 ¹⁶ atoms / cm ³ or less.

In addition, when nitrogen is contained in the oxide semiconductor included in the semiconductor layer, electrons serving as carriers are generated, the carrier density is increased, and the oxide semiconductor is likely to be n-type. As a result, a transistor including an oxide semiconductor containing nitrogen is likely to be normally on. For this reason, it is preferable that the nitrogen concentration obtained by secondary ion mass spectrometry in the semiconductor layer is 5 × 10 ¹⁸ atoms / cm ³ or less.

The semiconductor layer may have a non-single crystal structure, for example. The non-single-crystal structure includes, for example, a CAAC-OS (C-Axis Crystalline Oxide Semiconductor Semiconductor having a crystal oriented in the c-axis, or a C-Axis Aligned and A-B-Plane Annealed Crystal Oxide Crystal Structure, Includes a microcrystalline structure or an amorphous structure. In the non-single-crystal structure, the amorphous structure has the highest density of defect states, and the CAAC-OS has the lowest density of defect states.

An oxide semiconductor film having an amorphous structure has, for example, disordered atomic arrangement and no crystal component. Alternatively, an amorphous oxide film has, for example, a completely amorphous structure and does not have a crystal part.

Note that the semiconductor layer may be a mixed film including two or more of an amorphous structure region, a microcrystalline structure region, a polycrystalline structure region, a CAAC-OS region, and a single crystal structure region. Good. For example, the mixed film may have a single-layer structure or a stacked structure including any two or more of the above-described regions.
<Configuration of CAC-OS>
A structure of a CAC (Cloud Aligned Complementary) -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 a 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 a configuration in which uniformly distributed in the film (hereinafter Also referred to as a cloud-like.) A.

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

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

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

On the other hand, CAC-OS relates to a material structure of an oxide semiconductor. CAC-OS refers to a region observed in the form of nanoparticles mainly composed of Ga in a material structure including In, Ga, Zn and O, and nanoparticles mainly composed 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, and In _{X2 Zn} Y2 _{O Z2} or _{InO X1} is the main component region, in some cases clear boundary can not be observed.

In place of gallium, aluminum, yttrium, copper, vanadium, beryllium, boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium are selected. In the case where one or a plurality of types are included, the CAC-OS includes a region that is observed in a part of a nanoparticle mainly including the metal element and a nanoparticle 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 under a condition where the substrate is not intentionally heated, for example. 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. .

The CAC-OS is characterized in that no clear peak is observed when it is measured using a θ / 2θ scan by the out-of-plane method, which is one of the 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, in an electron beam diffraction pattern obtained by irradiating an electron beam with a probe diameter of 1 nm (also referred to as a nanobeam electron beam), a ring-shaped high luminance region and a plurality of regions in the ring region are provided. A bright spot 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.

In addition, for example, in a CAC-OS in an In—Ga—Zn oxide, GaO _X3 is a main component by EDX mapping obtained by using energy dispersive X-ray spectroscopy (EDX: Energy Dispersive X-ray spectroscopy). It can be confirmed that the region and the region mainly composed of In _X2 Zn _Y2 O _Z2 or InO _X1 are 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 each region is mainly composed of each element. Has a mosaic structure.

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

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

Therefore, when CAC-OS is used for a semiconductor element, the insulating property caused by GaO _{X3 and the} like and the conductivity caused by In _X2 Zn _Y2 O _Z2 or InO _X1 act complementarily, thereby increasing the 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.

Alternatively, 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.

The bottom-gate transistor described in this embodiment is preferable because the number of manufacturing steps can be reduced. At this time, since amorphous silicon can be used at a lower temperature than polycrystalline silicon, it is possible to use a material having low heat resistance as the electrode material and substrate material for the wiring below the semiconductor layer. Can widen the choice of materials. For example, a glass substrate having an extremely large area can be suitably used. On the other hand, a top-gate transistor is preferable because an impurity region can be easily formed in a self-aligning manner and variation in characteristics can be reduced. At this time, it is particularly suitable when polycrystalline silicon, single crystal silicon or the like is used.

[Conductive layer]
In addition to the gate, source, and drain of a transistor, materials that can be used for conductive layers such as various wirings and electrodes that constitute a display device include aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, A metal such as tantalum or tungsten, or an alloy containing the same as a main component can be given. A film containing any of these materials can be used as a single layer or a stacked structure. For example, a single layer structure of an aluminum film containing silicon, a two layer structure in which an aluminum film is stacked on a titanium film, a two layer structure in which an aluminum film is stacked on a tungsten film, and a copper film on a copper-magnesium-aluminum alloy film Two-layer structure to stack, two-layer structure to stack copper film on titanium film, two-layer structure to stack copper film on tungsten film, titanium film or titanium nitride film, and aluminum film or copper film on top of it A three-layer structure for forming a titanium film or a titanium nitride film thereon, a molybdenum film or a molybdenum nitride film, and an aluminum film or a copper film stacked thereon, and a molybdenum film or a There is a three-layer structure for forming a molybdenum nitride film. Note that an oxide such as indium oxide, tin oxide, or zinc oxide may be used. Further, it is preferable to use copper containing manganese because the controllability of the shape by etching is increased.

As the light-transmitting conductive material, conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide to which gallium is added, or graphene can be used. Alternatively, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, or an alloy material containing the metal material can be used. Alternatively, a nitride (eg, titanium nitride) of the metal material may be used. Note that in the case where a metal material or an alloy material (or a nitride thereof) is used, it may be thin enough to have a light-transmitting property. In addition, a stacked film of the above materials can be used as a conductive layer. For example, it is preferable to use a laminated film of an alloy of silver and magnesium and indium tin oxide because the conductivity can be increased. These can also be used for conductive layers such as various wirings and electrodes constituting the display device and conductive layers (conductive layers functioning as pixel electrodes and common electrodes) included in the display element.

[Insulation layer]
Insulating materials that can be used for each insulating layer include, for example, resins such as acrylic and epoxy, resins having a siloxane bond, and inorganic insulation such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide. Materials can also be used.

In addition, the light-emitting element is preferably provided between a pair of insulating films with low water permeability. Thereby, impurities such as water can be prevented from entering the light emitting element, and a decrease in reliability of the apparatus can be suppressed.

Examples of the low water-permeable insulating film include a film containing nitrogen and silicon such as a silicon nitride film and a silicon nitride oxide film, and a film containing nitrogen and aluminum such as an aluminum nitride film. Alternatively, a silicon oxide film, a silicon oxynitride film, an aluminum oxide film, or the like may be used.

For example, the water vapor transmission rate of an insulating film with low water permeability is 1 × 10 ⁻⁵ [g / (m ² · day)] or less, preferably 1 × 10 ⁻⁶ [g / (m ² · day)] or less, More preferably, it is 1 × 10 ⁻⁷ [g / (m ² · day)] or less, and further preferably 1 × 10 ⁻⁸ [g / (m ² · day)] or less.

[Liquid crystal element]
As the liquid crystal element, for example, a liquid crystal element to which a vertical alignment (VA: Vertical Alignment) mode is applied can be used. As the vertical alignment mode, an MVA (Multi-Domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, an ASV (Advanced Super View) mode, or the like can be used.

As the liquid crystal element, liquid crystal elements to which various modes are applied can be used. For example, in addition to the VA mode, a TN (Twisted Nematic) mode, an IPS (In-Plane-Switching) mode, an FFS (Fringe Field Switching) mode, an ASM (Axially Symmetrical Aligned Micro-cell) mode, Further, a liquid crystal element to which an FLC (Ferroelectric Liquid Crystal) mode, an AFLC (Antiferroelectric Liquid Crystal) mode, or the like is applied can be used.

Note that a liquid crystal element is an element that controls transmission or non-transmission of light by an optical modulation action of liquid crystal. Note that the optical modulation action of the liquid crystal is controlled by an electric field applied to the liquid crystal (including a horizontal electric field, a vertical electric field, or an oblique electric field). As the liquid crystal used in the liquid crystal element, a thermotropic liquid crystal, a low molecular liquid crystal, a polymer liquid crystal, a polymer dispersed liquid crystal (PDLC), a ferroelectric liquid crystal, an antiferroelectric liquid crystal, or the like is used. Can do. These liquid crystal materials exhibit a cholesteric phase, a smectic phase, a cubic phase, a chiral nematic phase, an isotropic phase, and the like depending on conditions.

Further, as the liquid crystal material, either a positive type liquid crystal or a negative type liquid crystal may be used, and an optimal liquid crystal material may be used according to an applied mode or design.

An alignment film can be provided to control the alignment of the liquid crystal. Note that in the case of employing a horizontal electric field mode, liquid crystal exhibiting a blue phase for which an alignment film is unnecessary may be used. The blue phase is one of the liquid crystal phases. When the temperature of the cholesteric liquid crystal is increased, the blue phase appears immediately before the transition from the cholesteric phase to the isotropic phase. Since the blue phase appears only in a narrow temperature range, a liquid crystal composition mixed with several percent by weight or more of a chiral agent is used for the liquid crystal layer in order to improve the temperature range. A liquid crystal composition containing a liquid crystal exhibiting a blue phase and a chiral agent has a short response speed and is optically isotropic. In addition, a liquid crystal composition including a liquid crystal exhibiting a blue phase and a chiral agent does not require alignment treatment and has a small viewing angle dependency. Further, since it is not necessary to provide an alignment film, a rubbing process is not required, so that electrostatic breakdown caused by the rubbing process can be prevented, and defects or breakage of the liquid crystal display device during the manufacturing process can be reduced. .

As the liquid crystal element, a transmissive liquid crystal element, a reflective liquid crystal element, a transflective liquid crystal element, or the like can be used.

In one embodiment of the present invention, a reflective liquid crystal element can be used.

In the case of using a transmissive or transflective liquid crystal element, two polarizing plates are provided so as to sandwich a pair of substrates. A backlight is provided outside the polarizing plate. The backlight may be a direct type backlight or an edge light type backlight. It is preferable to use a direct-type backlight including an LED (Light Emitting Diode) because local dimming is facilitated and contrast can be increased. An edge light type backlight is preferably used because the thickness of the module including the backlight can be reduced.
Therefore, it is preferable.

In the case of using a reflective liquid crystal element, a polarizing plate is provided on the display surface side. Separately from this, it is preferable to arrange a light diffusing plate on the display surface side because the visibility can be improved.

In the case of using a reflective or transflective liquid crystal element, a front light may be provided outside the polarizing plate. As the front light, an edge light type front light is preferably used. It is preferable to use a front light including an LED (Light Emitting Diode) because power consumption can be reduced.

[Light emitting element]
As the light-emitting element, an element capable of self-emission can be used, and an element whose luminance is controlled by current or voltage is included in its category. For example, an LED, an organic EL element, an inorganic EL element, or the like can be used.

Light emitting elements include a top emission type, a bottom emission type, and a dual emission type. A conductive film that transmits visible light is used for the electrode from which light is extracted. In addition, a conductive film that reflects visible light is preferably used for the electrode from which light is not extracted.

The EL layer has at least a light emitting layer. The EL layer is a layer other than the light-emitting layer, such as a substance having a high hole-injecting property, a substance having a high hole-transporting property, a hole blocking material, a substance having a high electron-transporting property, a substance having a high electron-injecting property, A layer including a substance (a substance having a high electron transporting property and a high hole transporting property) or the like may be further included.

In the EL layer, either a low molecular compound or a high molecular compound can be used, and an inorganic compound may be included. The layers constituting the EL layer can be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), a transfer method, a printing method, an ink jet method, or a coating method.

When a voltage higher than the threshold voltage of the light emitting element is applied between the cathode and the anode, holes are injected into the EL layer from the anode side and electrons are injected from the cathode side. The injected electrons and holes are recombined in the EL layer, and the light-emitting substance contained in the EL layer emits light.

In the case where a white light-emitting element is used as the light-emitting element, the EL layer preferably includes two or more light-emitting substances. For example, white light emission can be obtained by selecting the light emitting material so that the light emission of each of the two or more light emitting materials has a complementary color relationship. For example, a light emitting material that emits light such as R (red), G (green), B (blue), Y (yellow), and O (orange), or spectral components of two or more colors of R, G, and B It is preferable that 2 or more are included among the luminescent substances which show light emission containing. In addition, it is preferable to apply a light-emitting element whose emission spectrum from the light-emitting element has two or more peaks in a wavelength range of visible light (for example, 350 nm to 750 nm). The emission spectrum of the material having a peak in the yellow wavelength region is preferably a material having spectral components in the green and red wavelength regions.

The EL layer preferably has a structure in which a light-emitting layer including a light-emitting material that emits one color and a light-emitting layer including a light-emitting material that emits another color are stacked. For example, the plurality of light emitting layers in the EL layer may be stacked in contact with each other, or may be stacked through a region not including any light emitting material. For example, a region including the same material (for example, a host material or an assist material) as the fluorescent light emitting layer or the phosphorescent light emitting layer and not including any light emitting material is provided between the fluorescent light emitting layer and the phosphorescent light emitting layer. Also good. This facilitates the production of the light emitting element and reduces the driving voltage.

The light-emitting element may be a single element having one EL layer or a tandem element in which a plurality of EL layers are stacked with a charge generation layer interposed therebetween.

The conductive film that transmits visible light can be formed using, for example, indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide to which gallium is added, or the like. In addition, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, or titanium, an alloy containing these metal materials, or a nitride of these metal materials (for example, Titanium nitride) can also be used by forming it thin enough to have translucency. In addition, a stacked film of the above materials can be used as a conductive layer. For example, it is preferable to use a stacked film of an alloy of silver and magnesium and indium tin oxide because the conductivity can be increased. Further, graphene or the like may be used.

For the conductive film that reflects visible light, for example, a metal material such as aluminum, gold, platinum, silver, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy including these metal materials is used. Can do. In addition, lanthanum, neodymium, germanium, or the like may be added to the metal material or alloy. Alternatively, titanium, nickel, or neodymium and an alloy containing aluminum (aluminum alloy) may be used. Alternatively, an alloy containing copper, palladium, magnesium, and silver may be used. An alloy containing silver and copper is preferable because of its high heat resistance. Furthermore, oxidation can be suppressed by stacking a metal film or a metal oxide film in contact with the aluminum film or the aluminum alloy film. Examples of materials for such metal films and metal oxide films include titanium and titanium oxide. Alternatively, the conductive film that transmits visible light and a film made of a metal material may be stacked. For example, a laminated film of silver and indium tin oxide, a laminated film of an alloy of silver and magnesium and indium tin oxide, or the like can be used.

The electrodes may be formed using a vapor deposition method or a sputtering method, respectively. In addition, it can be formed using a discharge method such as an inkjet method, a printing method such as a screen printing method, or a plating method.

Note that the above-described light-emitting layer and a layer containing a substance having a high hole-injecting property, a substance having a high hole-transporting property, a substance having a high electron-transporting property, a substance having a high electron-injecting property, a bipolar substance, Each may have an inorganic compound such as a quantum dot or a polymer compound (oligomer, dendrimer, polymer, etc.). For example, a quantum dot can be used for a light emitting layer to function as a light emitting material.

As the quantum dot material, a colloidal quantum dot material, an alloy type quantum dot material, a core / shell type quantum dot material, a core type quantum dot material, or the like can be used. Alternatively, a material including an element group of Group 12 and Group 16, Group 13 and Group 15, or Group 14 and Group 16 may be used. Alternatively, a quantum dot material containing an element such as cadmium, selenium, zinc, sulfur, phosphorus, indium, tellurium, lead, gallium, arsenic, or aluminum may be used.

[Adhesive layer]
As the adhesive layer, various curable adhesives such as an ultraviolet curable photocurable adhesive, a reactive curable adhesive, a thermosetting adhesive, and an anaerobic adhesive can be used. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenol resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, EVA (ethylene vinyl acetate) resins, and the like. In particular, a material with low moisture permeability such as an epoxy resin is preferable. Alternatively, a two-component mixed resin may be used. Further, an adhesive sheet or the like may be used.

Further, the resin may contain a desiccant. For example, a substance that adsorbs moisture by chemical adsorption, such as an alkaline earth metal oxide (such as calcium oxide or barium oxide), can be used. Alternatively, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used. The inclusion of a desiccant is preferable because impurities such as moisture can be prevented from entering the element and the reliability of the display panel is improved.

In addition, light extraction efficiency can be improved by mixing a filler having a high refractive index or a light scattering member with the resin. For example, titanium oxide, barium oxide, zeolite, zirconium, or the like can be used.

(Connection layer)
As the connection layer, an anisotropic conductive film (ACF: Anisotropic Conductive Film), an anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

(Colored layer)
Examples of materials that can be used for the colored layer include metal materials, resin materials, resin materials containing pigments or dyes, and the like.

[Light shielding layer]
Examples of the material that can be used for the light-shielding layer include carbon black, titanium black, metal, metal oxide, and composite oxide containing a solid solution of a plurality of metal oxides. The light shielding layer may be a film containing a resin material or a thin film of an inorganic material such as a metal. Alternatively, a stacked film of a film containing a material for the colored layer can be used for the light shielding layer. For example, a stacked structure of a film including a material used for a colored layer that transmits light of a certain color and a film including a material used for a colored layer that transmits light of another color can be used. It is preferable to use a common material for the coloring layer and the light-shielding layer because the apparatus can be shared and the process can be simplified.

This embodiment can be implemented in appropriate combination with at least part of the other embodiments described in this specification.
(Embodiment 4)
Electronic devices that can use the display device according to one embodiment of the present invention include a display device, a personal computer, an image storage device or an image playback device including a recording medium, a mobile phone, a portable game machine, and a portable data terminal , Digital book terminals, video cameras, digital still cameras and other cameras, goggles-type displays (head-mounted displays), navigation systems, sound playback devices (car audio, digital audio players, etc.), copiers, facsimiles, printers, printer multifunction devices Automatic teller machines (ATMs), vending machines, and the like. Specific examples of these electronic devices are shown in FIGS.

FIG. 17A illustrates a navigation system, which includes a housing 971, a display portion 973, operation keys 974, and the like. The display portion 973 is provided with a touch sensor and can perform main input operations. By using the display system of one embodiment of the present invention for the display portion 973, high-speed display, improved visibility, and low power consumption of the display portion 973 can be performed.

FIG. 17B illustrates a portable game machine including a housing 901, a housing 902, a display portion 903, a display portion 904, a microphone 905, a speaker 906, operation keys 907, a stylus 908, a camera 909, and the like. Note that the portable game machine illustrated in FIG. 17E includes two display portions 903 and 904; however, the number of display portions included in the portable game device is not limited thereto. By including the display device of one embodiment of the present invention in the display portion 903, high-speed display, improved visibility, and low power consumption of the display portion 903 can be performed.

FIG. 17C illustrates a digital camera, which includes a housing 961, a shutter button 962, a microphone 963, a speaker 967, a display portion 965, operation keys, and the like. By using the display device of one embodiment of the present invention for the display portion 965, high-speed display, improved visibility, and low power consumption of the display portion 965 can be performed.

FIG. 17D illustrates a wristwatch-type information terminal including a housing 931, a display portion 932, a wristband 933, operation buttons 935, a crown 936, a camera 939, and the like. The display unit 932 may be a touch panel. By using the display device of one embodiment of the present invention for the display portion 932, high-speed display, improved visibility, and low power consumption of the display portion 932 can be performed.

FIG. 17E illustrates an example of a mobile phone, which includes a housing 951, a display portion 952, operation buttons 953, an external connection port 954, a speaker 955, a microphone 956, a camera 957, and the like. The mobile phone includes a touch sensor in the display portion 952. All operations such as making a call or inputting characters can be performed by touching the display portion 952 with a finger or a stylus. By using the display device of one embodiment of the present invention for the display portion 952, high-speed display, improved visibility, and low power consumption of the display portion 952 can be performed.

FIG. 17F illustrates a portable data terminal including a housing 911, a display portion 912, a camera 919, and the like. Information can be input and output by a touch panel function of the display portion 912. The display portion 932 can perform high-speed display, improved visibility, and low power consumption according to the present invention.

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

DESCRIPTION OF SYMBOLS 10 Display apparatus 10b Display apparatus 20 Drive circuit 20b Drive circuit 21 Circuit 22 Circuit 25 Adder 25a Adder 25d Adder 26a Analog switch 26b Analog switch 26c Analog switch 26d Analog switch 26e Analog switch 26f Analog switch 27a Inverter 27d Inverter 27f Inverter 27g Inverter 28 NAND circuit 28a Op amp 28b Op amp 31 Drive circuit 31b Drive circuit 32 Drive circuit 40 Pixel array 40b Pixel array 45 Pixel unit 46 Pixel 46B Display element 46G Display element 46R Display element 47 Pixel 47B Display element 47G Display element 47R Display element 50 Data Processing circuit 55 Light 112 Liquid crystal 113 Conductive layer 117 Insulating layer 121 Insulating layer 130 Polarizing plate 131 Colored layer 132 Light shielding layer 33a Alignment film 133b Alignment film 134 Colored layer 141 Adhesive layer 142 Adhesion layer 191 Conductive layer 192 EL layer 193a Conductive layer 193b Conductive layer 201 Transistor 204 Connection portion 205 Transistor 206 Transistor 207 Connection portion 211 Insulation layer 212 Insulation layer 213 Insulation layer 214 Insulation Layer 215 insulating layer 216 insulating layer 217 insulating layer 220 insulating layer 221 conductive layer 222 conductive layer 223 conductive layer 224 conductive layer 231 semiconductor layer 242 connection layer 243 connection body 251 opening 252 connection portion 300 display panel 311 electrode 311a conductive layer 311b 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 Touch sensor 372 FPC
373 IC
400 Display device 410 Pixel 451 Opening 901 Housing 902 Housing 903 Display unit 904 Display unit 905 Microphone 906 Speaker 907 Operation key 908 Stylus 909 Camera 911 Housing 912 Display unit 919 Camera 931 Housing 932 Display unit 933 Wristband 935 Button 936 Crown 939 Camera 951 Case 952 Display unit 953 Operation button 954 External connection port 955 Speaker 956 Microphone 957 Camera 961 Case 962 Shutter button 963 Microphone 965 Display unit 967 Speaker 971 Case 973 Display unit 974 Operation key

Claims (8)

A display device having a drive circuit and a pixel unit,
The drive circuit includes a first circuit;
The pixel unit includes a first pixel and a second pixel,
The first circuit has a function of determining the gradation of input image data,
The first circuit has a function capable of inputting and outputting first digital data and second digital data;
The first circuit has a function of outputting the first digital data when the gradation of the second digital data is determined to be a first value;
The first circuit has a function of outputting the second digital data when the gradation of the second digital data is determined to be a second value;
The drive circuit has a function of converting the first digital data into first analog data and outputting the first analog data to the first pixel;
The display device having a function of converting the second digital data into second analog data and outputting the second digital data to the second pixel. A display device having a drive circuit and a pixel unit,
The drive circuit includes a first circuit;
The pixel unit includes a first pixel and a second pixel,
The first circuit has a function of determining the gradation of input image data,
The first circuit has a function of inputting / outputting first digital data, second digital data, third digital data, and fourth digital data,
The first circuit has a function of outputting the first digital data and the third digital data when the gradation of the second digital data is determined to be a first value,
The first circuit has a function of outputting the second digital data and the fourth digital data when the gradation of the second digital data is determined to be a second value.
The driving circuit converts the first digital data into first analog data when the first circuit determines that the gradation of the second digital data is the first value. A function of outputting to the first pixel, converting the third digital data into third analog data, and outputting the third analog data to the second pixel;
The drive circuit converts the second digital data into second analog data when the first circuit determines that the gradation of the second digital data is the second value. A display device having a function of outputting to the second pixel, converting the fourth digital data into fourth analog data, and outputting the fourth analog data to the first pixel. A display device having a drive circuit and a pixel unit,
The drive circuit has a first circuit and a second circuit;
The pixel unit includes a first pixel and a second pixel,
The first circuit has a function of determining the gradation of input image data,
The first circuit has a function capable of inputting and outputting first digital data and second digital data;
The second circuit has a function capable of inputting and outputting first analog data, second analog data, third analog data, and fourth analog data,
The first circuit has a function of outputting the first digital data when the gradation of the second digital data is determined to be a first value;
The first circuit has a function of outputting the second digital data when the gradation of the second digital data is determined to be a second value;
The driving circuit converts the first digital data into first analog data when the first circuit determines that the gradation of the second digital data is the first value. Having a function of inputting to the second circuit;
The drive circuit converts the second digital data into second analog data when the first circuit determines that the gradation of the second digital data is the second value. Having a function of inputting to the second circuit;
When the first circuit determines that the gray level of the second digital data is the first value, the second circuit converts the first analog data into the first analog data. The third analog data is output to the second pixel, and the third analog data is output to the second pixel.
When the first circuit determines that the gray level of the second digital data is the second value, the second circuit converts the second analog data to the second analog data. A display device having a function of outputting to the first pixel and outputting the fourth analog data to the first pixel. In any one of Claims 1 thru | or 3,
The first pixel has a first display element having a function of emitting visible light, and the second pixel has a second display element having a function of reflecting visible light. In any one of Claims 1 thru | or 4,
The display device, wherein the first value is a value indicating that the image is not a significant image, and the second value is a value indicating that the image is a significant image. In any one of Claims 1 thru | or 5,
The display device, wherein the first value is smaller than a threshold value representing a significant image, and the second value is not less than the threshold value. In any one of Claims 1 thru | or 6,
The display device in which each of the first pixel and the second pixel includes a transistor including a metal oxide in a semiconductor layer in which a channel is formed. It has a display device according to any one of claims 1 to 7,
An electronic device provided with a touch sensor at a position overlapping the display area.

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