JP2006337997A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device of which the display is visible in a dark place or under strong external light. <P>SOLUTION: The present invention is a display device which performs display, changing the grayscale number corresponding to the external light strength, and the display device which can switch the display mode corresponding to contents displayed on the screen. The display contents include a text display mode displaying mainly characters and symbols, etc., a picture display mode displaying images with a small number of colors such as a comic, a video mode displaying natural images with a large number of colors such as a photograph and a moving image, and the like. By switching the grayscale number arbitrarily according to these display modes, visibility can be ensured in a wide range from a dark place or under an indoor fluorescent light to under outdoor sunlight. For example, the grayscale number is switched so that display of from 2 to 8 grayscales is performed in the text display mode, display of from 4 to 16 grayscales is performed in the picture display mode, and display of from 64 to 1024 grayscales is performed in the video mode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device including a screen for displaying characters, still images, moving images, and the like, and relates to a technique for improving the visibility of the display screen under various usage environments.

  Various electric products having a display screen composed of a liquid crystal panel, such as mobile phones, have become widespread. Liquid crystal panels are thin and light, and mobile computers with liquid crystal panels are being produced in personal computers called notebook computers. In addition, a large number of information terminals called PDA (Personal Digital Assistant) are being produced and spread.

Although not limited to liquid crystal panels, display panels used for this type of application are often given the appearance of image quality, and are often equipped with functions to adjust brightness and contrast automatically or manually. It is popular. For example, there is known a liquid crystal display device having an adjustment function for increasing the visibility between gradations by changing the transmittance of the liquid crystal without increasing the luminance of the backlight of the liquid crystal panel (see Patent Document 1).
JP 2003-186455 A

  However, the liquid crystal panel has good visibility in an indoor environment of 300 lux to 700 lux, but has a problem that the visibility is significantly deteriorated in an outdoor environment of 1,000 lux or more. Although it is called a reflection type liquid crystal panel and has a configuration in which external light is reflected by the pixel electrode, the image quality is rather deteriorated under an indoor fluorescent lamp, so that an essential solution has not been achieved. That is, ensuring visibility in a wide range from a dark place or indoor fluorescent lamp to outdoor sunlight has not been solved.

  In view of the above, an object of the present invention is to provide a display device that can recognize the display even under strong external light from a dark place.

The present invention is a display device that performs display by changing the number of gradations according to the intensity of external light. That is, a display device having a contrast ratio (for example, white and black) of 50 or more, preferably 100 or more, which displays a low gradation when the external light intensity is high and displays a high gradation when the external light intensity is low. This is a display device that performs display and displays the intermediate gradation when the external light intensity is between them. If the display unit is brightness in all white signal input and from 50 cd / m ² and 5000 cd / m ^2, a display device is changed according Such a gradation number in the external light intensity.

  The present invention is a display device that performs display by changing the number of gradations according to the external light intensity, and is a display device that can switch the display mode according to the content displayed on the screen. Display contents include text display mode that displays mainly characters and symbols, picture display mode that displays images with a small number of colors such as cartoons, and images that display natural images with a large number of colors such as photographs and movies. Mode etc. are included.

  By appropriately switching the number of gradations according to these display modes, it is possible to ensure visibility in a wide range from a dark place or indoor fluorescent lamp to outdoor sunlight. For example, in the text display mode, 2 to 8 gradations are displayed, and in the picture display mode for displaying an image with a small number of colors such as a so-called cartoon, 4 to 16 gradations are displayed. In the video mode for displaying a natural image with a large number of colors such as a moving image, the display is switched so as to display from 64 gradations to 1024 gradations.

  The switching of the number of gradations according to the external light is, for example, a display device having a contrast ratio (for example, white and black) of 50 or more, preferably 100 or more, and the external light intensity is 100,000 lux. Display with 2 gradations, display with 2 to 8 gradations when the external light intensity is 10,000 to 100,000 lux, and external light intensity with 1,000 to 10,000 lux. Sometimes 4 to 16 gradations are displayed. When the external light intensity is 100 to 1,000 lux, 16 to 64 gradations are displayed. When the external light intensity is less than 100 lux. Display of 64 to 1024 gradations is performed.

  One aspect of the present invention is a display device that displays character information and a still image with a lower gradation than the display gradation at the time of strong external light intensity such as under sunny daylight. For example, in the environment of sunny daylight or cloudy daylight, 2 to 8 gradations, 1 hour before sunny day or 1 hour after cloudy daylight, or fluorescent light in the office This is a display device that performs display of 4 to 16 gradations in an indoor environment.

  In this case, after the external light intensity is increased, the gradation may be lowered and the display may be performed.

  One aspect of the present invention is a display device that detects external light intensity with an optical sensor, feeds back the value, changes a gradation, and displays an appropriate image. That is, external light intensity detecting means for receiving external light and outputting a signal corresponding to the external light intensity, gradation number control means for changing the number of gradations according to the signal, and the number of gradations And a signal processing means for sending the video signal to the display driving circuit.

  One aspect of the present invention is an external light intensity detection unit that receives external light and outputs a signal corresponding to the external light intensity, a gradation number control unit that changes the number of gradations according to the signal, and a level thereof. The display device includes signal processing means for sending video signals such as text (characters), still images, and moving images to the display drive circuit with a predetermined number of gradations in conjunction with the frequency control means.

  As described above, the gradation number control means for changing the number of gradations according to the external light intensity is provided between the external light intensity detection means and the signal processing means for sending the video signal to the drive circuit on the display panel side. Thus, the visibility of information displayed on the display screen can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the display apparatus excellent in visibility can be provided by controlling the number of gradations of a display image according to external light intensity | strength. That is, it is possible to obtain a display device that ensures visibility in a wide range from a dark place or under an indoor fluorescent lamp to outdoor sunlight.

  Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that modes and details can be variously changed 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 the structures of the present invention described below, the same reference numerals are used in different drawings.

(Embodiment 1)
FIG. 1 shows an embodiment of the present invention. FIG. 1 is a block diagram of a display device according to this embodiment. The display device 100 includes a controller 101, a memory 102, an optical sensor 103, an amplifier 104, a power source 105, and a display panel 106.

  The controller 101 generates a signal necessary for driving the display panel 106 based on a control signal and a video signal input from the outside and an optical sensor signal supplied from the amplifier 104. Then, these signals are supplied to the display panel 106. The memory 102 is mainly used for temporarily storing a video signal. The memory 102 is also used for storing information other than the video signal. The optical sensor 103 detects external light (external light received by the display device 100). The output is supplied to the amplifier 104. The amplifier 104 amplifies the electrical signal output from the optical sensor 103 and supplies the amplified electrical signal to the controller 101. Note that the amplifier 104 may be omitted if the electrical signal output from the optical sensor 103 is sufficiently large. The power source 105 supplies a necessary voltage or current to the display panel 106. Note that the display panel 106 uses an electroluminescence (EL) element. In addition, it can be applied to FED (Field Emission Display).

  The display device 100 changes the total number of gradations of the image displayed on the display screen of the display panel 106 based on the output of the optical sensor 103. As the optical sensor 103, a photodiode or a phototransistor can be used. Specifically, when the display device 100 receives strong external light and the output of the optical sensor 103 exceeds a certain value, the total number of gradations of the image displayed on the display screen of the display panel 106 is reduced. When the display device 100 receives strong external light, the distinction between a certain gradation and a certain gradation is not clear, and the image displayed on the display screen of the display panel 106 is blurred. However, as described above, by reducing the total number of gradations according to the external light received by the display device 100, the distinction between a certain gradation and a certain gradation is clarified, and the display on the display panel 106 is displayed. The visibility of the screen can be improved.

  Further, when the total gradation of the image displayed on the display screen of the display panel 106 is set to two gradations by the output of the optical sensor 103, normally, a black background display image is displayed on the white background image. The display image of white background may be displayed on the background image of black background by inverting it. Then, the visibility of the display screen can be further improved. Further, the visibility of the display screen can be further improved by increasing the brightness of the white display image. The combination of the background image and the display image is not limited to white display on a black background, and any combination of colors can be used as long as the contrast is easy to take (the contrast ratio is clear).

  The output of the optical sensor 103 is sent to the controller 101 via the amplifier 104. The controller 101 detects whether the output of the optical sensor 103 is equal to or greater than a certain value by using the gradation output selection unit 108. When the output of the optical sensor 103 is not greater than a certain value, the total number of gradations of the video signal output to the display panel 106 is not changed. On the other hand, when the output of the optical sensor 103 is equal to or greater than a certain value, the total number of gradations of the video signal output to the display panel 106 is corrected to be low. The gradation conversion unit 107 changes the number of gradations of the video signal. These video signals are stored in the memory 102. Based on the output of the optical sensor 103, a video signal having a total number of gradations suitable for external light is selected by the gradation output selection unit 108 and supplied to the display panel 106.

As shown in Table 1, the indoor and outdoor brightness varies depending on lighting conditions, weather conditions such as weather, and time. For example, the illuminance in a room with illumination is about 800 lux to about 1,000 lux, the illuminance under cloudy weather in the daytime is about 32,000 lux, and the illuminance under sunny daytime reaches 100,000 lux.

Under such various brightness conditions, display panels (EL panels) using electroluminescence, transmissive liquid crystal panels (transmissive LCD panels), transflective liquid crystal panels (semitransmissive LCD panels), reflection Table 2 shows the results of comparing the visibility of the liquid crystal panel (reflection type LCD).

  As a result, in environments with brightness up to about 1,500 lux (mainly indoors, illuminated halls, etc.), display patterns (natural images, text (characters, Good visibility was obtained regardless of the symbol). On the other hand, under 10,000 lux (during cloudy daytime), the EL panel and transmissive liquid crystal panel display a large amount of visibility in low contrast areas such as halftone areas when displaying natural images. There was a tendency to decrease. However, even in this case, the visibility of the EL panel was better than that of the transmissive liquid crystal panel. Further, in the EL panel, the visibility is restored when the number of gradations is reduced (from 2 to 8 gradations), and visibility that is practically satisfactory for text display is obtained. On the other hand, in the transflective liquid crystal panel, good visibility was obtained under an environment of 10,000 lux although the contrast was slightly low overall in an indoor to outdoor environment. In terms of power consumption, reflective liquid crystal panels are excellent, but there is a tendency for visibility to deteriorate in environments with relatively low illuminance such as indoors. In the transmissive liquid crystal panel, since the backlight consumes power, the power consumption is higher than that of the reflective liquid crystal panel. On the other hand, in the EL panel, low power consumption is achieved in the display mode in which the number of gradations is reduced.

  As can be seen from Table 2, the EL panel is used and the display mode is adjusted in the number of gradations according to the external light intensity, thereby ensuring visibility in an environment from indoors to outdoors while reducing power consumption. It is possible to provide a display device that achieves the above.

For example, in the display device 100 shown in FIG. 1, when the output of the optical sensor 103 detects that the display device 100 receives external light of 10 lux to 100 lux, the total number of gradations starts from 64 gradations. It is not changed as 1024 gradations. Further, when it is detected from the output of the optical sensor 103 that the display device 100 receives external light of 100 to 1,000 lux, the total number of gradations is corrected from 16 to 64 gradations. Further, when it is detected from the output of the optical sensor 103 that the display device 100 receives external light of 1,000 lux to 10,000 lux, the total number of gradations is corrected from 4 to 16 gradations. To do. Further, when it is detected from the output of the optical sensor 103 that the display device 100 receives external light of 10,000 lux to 100,000 lux, the total number of gradations is corrected from 2 gradations to 4 gradations. To do.
The correction of the number of gradations with respect to the brightness of outside light is not limited to the above example. Generally, the number of gradations is i when the intensity of external light is x lux, the number of gradations is j when the intensity of external light is y lux, and the number of gradations is k when the intensity of external light is z lux. The natural numbers i, j, and k satisfy the equation i>j> k, and the positive real numbers x, y, and z satisfy the equation x <y <z.

  The controller 101 is supplied with an analog video signal from the outside. In the case where the display screen of the display panel 106 performs analog gradation display, and the total number of gradations of the standard video signal is 64 gradations, the total number of gradations is 32 gradations, 16 gradations, Each of the video signals of 8 gradations and 4 gradations is generated by the gradation conversion unit 107, and these video signals are stored in the memory 102. Based on the output of the optical sensor 103, a video signal having a total number of gradations suitable for external light is selected by the gradation output selection unit 108 and supplied to the display panel 106.

  When the display screen of the display panel 106 performs digital gradation display, the controller 101 converts an analog video signal into a digital video signal. When the total number of gradations of the standard video signal is 6 bits (64 gradations), 5 bits (32 gradations), 4 bits (16 gradations), 3 bits (8 gradations), 2 bits in advance A video signal of (4 gradations) is generated by the gradation conversion unit 107 in advance. These video signals are stored in the memory 102. Then, based on the output of the optical sensor 103, a video signal having a total number of gradations suitable for external light is selected by the gradation output selection unit 108 and supplied to the panel 306.

  The number of gradations may be changed depending on the image displayed on the display screen of the display panel 106. For example, there is a mode for displaying a still image and displaying text such as characters and icons. In this case, the total number of gradations is changed from 2 gradations to 8 gradations. Further, there is a mode for displaying still images and displaying images. In this case, the total number of gradations is changed from 4 gradations to 16 gradations. There is also a mode for displaying moving images. In this case, the total number of gradations is changed from 16 gradations to 64 gradations, or from 16 gradations to 1024 gradations. In this manner, power consumption can be reduced by changing the number of gradations according to each mode. The mode may be determined by the controller 101 based on the video signal supplied to the controller 101.

  The display device 100 may be provided with a selection switch for the user to select a display mode. Then, the user may select the above mode by operating a selection switch. Even when the display mode is selected by the selection switch, the gradation of the selected display mode may be automatically increased or decreased according to the (external light intensity) by the signal of the optical sensor 103.

  FIG. 2 shows a mode of a mobile phone capable of switching the display mode in accordance with the external light intensity. A cellular phone illustrated in FIG. 2A includes a first housing 201, a second housing 202, a display screen 203, a speaker 204, an antenna 205, a hinge 206, a keyboard 207, a microphone 208, and an optical sensor 209. Yes. The display device of the present invention is mounted in the first housing 201.

  FIG. 2A shows a display when the outside light is weak. On the display screen 203, black characters are displayed on a white background image. When the outside light is weak, the sensitivity of the eyes is matched with the light emission luminance of the display screen.

  FIG. 2B shows a display when the outside light is strong. When the external light is strong, the white background image is lost to the external light. Therefore, the optical sensor 209 detects the intensity of the external light and changes the background image to a black background as shown in FIG. By making the background image black in this way, the area of the light emitting portion can be reduced. The white portion can be displayed more clearly by concentrating the power on the few white display portions.

  Although mobile phones have been described in this embodiment mode, the present invention is not limited thereto, and the present invention is applied to electronic devices using various display devices such as PDAs, video cameras, digital cameras, portable DVDs, portable televisions, game machines, and computers. Can be used.

(Embodiment 2)
One example of a pixel in the display device described in Embodiment 1 is described. FIG. 3 shows an example of a pixel of a display device that can operate in a time gray scale method. 3 includes thin film transistors (hereinafter also referred to as “TFTs”). FIG. 3 shows a pixel for driving the light emitting element 303 with time gradation. This pixel includes a light emitting element 303, a driving TFT 302, a storage capacitor 304, and a switching TFT 301. The gate of the switching TFT 301 is connected to the gate signal line G 1 and is turned on when the gate signal line G 1 becomes high, and the data of the source signal line S 1 is written to the storage capacitor 304 and the gate of the driving TFT 302. When the driving TFT 302 is turned on, a current flows from the power supply line V 1 to the light emitting element 303 through the driving TFT 302. This state is maintained until the next writing is performed.

  FIG. 3B shows a timing chart of time gradation. In this example, description will be made by taking 4 bits as an example, but it is not limited to 4 bits. One frame is composed of four subframes SF1 to SF4. Each subframe is composed of an address period Ta1 to Ta4 (writing period) and a sustain period Ts1 to Ts4 (lighting period). By setting the sustain period Ts1: Ts2: Ts3: Ts4 = 8: 4: 2: 1, each bit corresponds to the sustain period, and time gradation is possible. At this time, lighting is not performed during the address period, and only addressing is performed.

(Embodiment 3)
In the display device shown in Embodiment Mode 2, as shown in Embodiment Mode 1, as shown in FIG. In this example, a 4-bit digital video signal is subjected to subframe conversion, but is not particularly limited to 4 bits. The operation will be described below. First, the control circuit 402 inputs a digital video signal to the first memory 404 via the switch 403. When all the data of the first frame is input to the first memory 404, the switch 403 is switched to the second memory 405, and the digital video signal of the second frame is written. By this means, it is possible to display a combination of a black background display image on a white background image or a combination of a white background display image on a black background image. The output of the video signal selection switch 406 is input to the switch 407, and it can be selected whether the signal of the video signal selection switch 406 is input to the display panel 401 as it is or is input in an inverted manner. If light-dark reversal is required, it may be reversed before input. This selection is made by the display controller.

(Embodiment 4)
FIG. 5 illustrates one mode of a mobile phone using a double-sided light emitting display panel. A cellular phone illustrated in FIG. 5 includes a first housing 501, a second housing 502, a first display screen 503, a second display screen 504, a third display screen 505, a speaker 506, an antenna 507, and a hinge 508. , A keyboard 509, a microphone 510, a battery 511, and an optical sensor. FIG. 5 shows a state in which the external light is strong and the background image is black. FIG. 5 (A) shows a view with the inside opened, FIG. 5 (B) shows the outside, and FIG. 5 (C) shows the side. The display device of the present invention is mounted in the first housing 501.

  In FIG. 5, the first display screen 503 is a main display and the second display screen 504 is a sub-display and two screens are illustrated, but the number is not limited. The display area of the sub display is smaller than the display area of the main display.

  In such a cellular phone, the system shown in FIG. 4 is capable of reversing the image horizontally using a control circuit and a memory circuit. In FIG. 4, first, the control circuit 402 inputs a digital video signal to the first memory 404 via the switch 403. When all the data of the first frame is input to the first memory 404, the switch 403 is switched to the second memory 405, and the digital video signal of the second frame is written.

  On the other hand, the video signal selection switch 406 is sequentially connected from the first memory 404 (1) to the first memory 404 (4) in the meantime, and inputs a signal stored in the first memory 404 to the display panel 401. When all the data of the second frame is input to the second memory 405, the switch 403 is switched to the first memory 404, and the digital video signal of the third frame is written. In addition, the video signal selection switch 406 is sequentially connected from the second memory 405 (1) to the second memory 405 (4) in the meantime, and inputs a signal stored in the second memory 405 to the display panel 401. By repeating the above, a subframe can be formed.

  When the video is reversed left and right, when the first memory 404 or the second memory 405 is called, the signal for each column of the display is called in reverse. In such a display device that performs subframe conversion, it is possible to cope with double-sided light emission by changing the memory calling order.

(Embodiment 5)
FIG. 6 shows a concept of a double-sided light emitting display panel used in the mobile phone of the fourth embodiment. In FIG. 6, a transparent electrode or an equivalent electrode 603, an electrode 604, an electrode 605, and an electrode 609 exist between two transparent substrates 601, 602, and an EL layer 606, an EL layer that develops electroluminescence between these electrodes. 607 and an EL layer 608 are sandwiched. A color filter 610, a color filter 611, and a color filter 612 are disposed on the transparent substrate 601, and when the EL layer 606, the EL layer 607, and the EL layer 608 emit white light, a full color display is displayed on the first light emitting surface. White display is possible on the second light emitting surface. The light emitters may be color-coded without using a color filter. In that case, the colors that can be displayed on the first light-emitting surface and the second light-emitting surface are the same.

(Embodiment 6)
One mode of a pixel structure of the display device described in any of Embodiments 1 to 5 will be described with reference to FIGS. FIG. 7 is a cross-sectional view of a pixel including a thin film transistor (TFT) and a light emitting element connected thereto.

  In FIG. 7, a blocking layer 701, a semiconductor layer 702 constituting the TFT 750, and a semiconductor layer 712 constituting one electrode of the capacitor portion 751 are formed over a substrate 700. A first insulating layer 703 is formed thereover, and functions as a gate insulating layer in the TFT 750 and a dielectric layer for forming a capacitor in the capacitor 751.

  A conductive layer 754 that forms the gate electrode 704 and the other electrode of the capacitor portion 751 is formed over the first insulating layer 703. A wiring 707 connected to the TFT 750 is connected to the first electrode 708 of the light emitting element 752. The first electrode 708 is formed on the third insulating layer 706. A second insulating layer 705 may be formed between the first insulating layer 703 and the third insulating layer 706. The light emitting element 752 includes a first electrode 708, an EL layer 709, and a second electrode 710. In addition, a fourth insulating layer 711 is formed so as to cover a peripheral end portion of the first electrode 708 and a connection portion between the first electrode 708 and the wiring 707.

  Next, the detail of the structure shown above is demonstrated. As the substrate 700, for example, a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, a ceramic substrate, or the like can be used. Alternatively, a metal substrate containing stainless steel or a semiconductor substrate with an insulating film formed on the surface thereof may be used. A substrate made of a synthetic resin having flexibility such as plastic may be used. The surface of the substrate 700 may be planarized by polishing such as a chemical mechanical polishing (CMP) method.

  As the blocking layer 701, an insulating film such as silicon oxide, silicon nitride, or silicon nitride oxide can be used. The blocking layer 701 can prevent alkali metal such as Na and alkaline earth metal contained in the substrate 700 from diffusing into the semiconductor layer 702 and adversely affecting the characteristics of the TFT 750. In FIG. 7, the blocking layer 701 has a single-layer structure, but it may be formed of two or more layers. Note that the blocking layer 701 is not necessarily provided when diffusion of impurities such as a quartz substrate does not cause a problem.

In addition, the surface of the glass substrate is directly irradiated with high-density plasma excited by microwaves, having an electron temperature of 2 eV or less, an ion energy of 5 eV or less, and an electron density of about 1 × 10 ¹¹ to 5 × 10 ¹³ / cm ^3. It may be processed. Plasma generation can be performed using a microwave-excited plasma processing apparatus using a radial slot antenna. At this time, when a nitride gas such as nitrogen (N ₂ ), ammonia (NH ₃ ), or nitrous oxide (N ₂ O) is introduced, the surface of the glass substrate can be nitrided. Since the nitride layer formed on the surface of the glass substrate contains silicon nitride as a main component, it can be used as a blocking layer for impurities diffused from the glass substrate side. A blocking layer 701 may be formed by forming a silicon oxide film or a silicon oxynitride film on the nitride layer by a plasma CVD method.

  In addition, by performing similar plasma treatment on the surface of the blocking layer 701 using silicon oxide, silicon oxynitride, or the like, nitriding treatment can be performed at a depth of 1 nm to 10 nm from the surface and the surface. This very thin silicon nitride layer can be used as a blocking layer without affecting the semiconductor layer formed thereon.

  As the semiconductor layer 702 and the semiconductor layer 712, a crystalline semiconductor film divided into island shapes is preferably used. The crystalline semiconductor film can be obtained by crystallizing an amorphous semiconductor film. As a crystallization method, a laser crystallization method, a thermal crystallization method using an RTA or a furnace annealing furnace, a thermal crystallization method using a metal element that promotes crystallization, or the like can be used. The semiconductor layer 702 includes a channel formation region and a pair of impurity regions to which an impurity element imparting one conductivity type is added. Note that an impurity region to which the impurity element is added at a low concentration may be provided between the channel formation region and the pair of impurity regions. The semiconductor layer 712 can have a structure in which an impurity element imparting one conductivity type or the opposite conductivity type is added to the whole.

The first insulating layer 703 can be formed using silicon oxide, silicon nitride, silicon nitride oxide, or the like by stacking a single layer or a plurality of films. In this case, the surface of the insulating film is excited by microwaves as described above, the electron temperature is 2 eV or less, the ion energy is 5 eV or less, and the electron density is about 1 × 10 ¹¹ to 5 × 10 ¹³ / cm ^3. It may be densified by oxidation or nitriding by high density plasma treatment. This treatment may be performed prior to the formation of the first insulating layer 703. That is, plasma treatment is performed on the surface of the semiconductor layer 702. At this time, the substrate temperature is set to 300 ° C. to 450 ° C., and processing is performed in an oxidizing atmosphere (O ₂ , N ₂ O, etc.) or a nitriding atmosphere (N ₂ , NH _3, etc.). A good interface can be formed.

  As the gate electrode 704 and the conductive layer 754, a single layer or a stacked structure including one kind of element selected from Ta, W, Ti, Mo, Al, Cu, Cr, and Nd, or an alloy or a compound containing a plurality of such elements is used. be able to.

  The TFT 750 includes a semiconductor layer 702, a gate electrode 704, and a first insulating layer 703 between the semiconductor layer 702 and the gate electrode 704. In FIG. 7, the TFT 750 included in the pixel is connected to the first electrode 708 of the light emitting element 752. This TFT 750 has a multi-gate structure in which a plurality of gate electrodes 704 are arranged on a semiconductor layer 702. That is, a plurality of TFTs are connected in series. With such a configuration, an inadvertent increase in off current can be suppressed. In FIG. 7, the TFT 750 is shown as a top gate type TFT, but a bottom gate type TFT having a gate electrode below the semiconductor layer may be used, and gate electrodes are provided above and below the semiconductor layer. A dual gate TFT may be used.

  The capacitor portion 751 includes a first insulating layer 703 as a dielectric, and a semiconductor layer 712 and a conductive layer 754 that are opposed to each other with the first insulating layer 703 interposed therebetween as a pair of electrodes. Note that in FIG. 7, as a capacitor element provided in the pixel, one of a pair of electrodes is a semiconductor layer 712 formed at the same time as the semiconductor layer 702 of the TFT 750, and the other conductive layer 754 is a layer formed at the same time as the gate electrode 704. However, the present invention is not limited to this configuration.

The second insulating layer 705 is preferably a barrier insulating film that blocks ionic impurities, such as a silicon nitride film. This second insulating layer 705 is formed of silicon nitride or silicon oxynitride. The second insulating layer 705 includes a function as a protective film that prevents contamination of the semiconductor layer 702. After the second insulating layer 705 is deposited, the second insulating layer 705 may be hydrogenated by introducing hydrogen gas and performing high-density plasma treatment excited by microwaves as described above. Alternatively, the second insulating layer 705 may be nitrided and hydrogenated by introducing ammonia gas. Alternatively, oxygen nitriding treatment and hydrogenation treatment may be performed by introducing oxygen, N ₂ O gas, or the like and hydrogen gas. By this method, the surface of the second insulating layer 705 can be densified by performing nitriding treatment, oxidation treatment, or oxynitridation treatment. Thereby, the function as a protective film can be strengthened. The hydrogen introduced into the second insulating layer 705 is then subjected to a heat treatment at 400 ° C. to 450 ° C., thereby releasing hydrogen from silicon nitride forming the second insulating layer 705, thereby hydrogenating the semiconductor layer 702. can do.

  As the third insulating layer 706, an inorganic insulating film or an organic insulating film can be used. As the inorganic insulating film, a silicon oxide film formed by a CVD method, a SOG (Spin On Glass) film (coated silicon oxide film), or the like can be used. As the organic insulating film, films of polyimide, polyamide, BCB (benzocyclobutene), acrylic, positive photosensitive organic resin, negative photosensitive organic resin, or the like can be used. For the third insulating layer 706, a material in which a skeleton structure is formed by a bond of silicon (Si) and oxygen (O) can be used. As a substituent of this material, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. A fluoro group may be used as a substituent. Alternatively, as a substituent, an organic group containing at least hydrogen and a fluoro group may be used.

  As the wiring 707, a single layer or a laminated structure made of one kind of element selected from Al, Ni, C, W, Mo, Ti, Pt, Cu, Ta, Au, and Mn or an alloy containing a plurality of such elements is used. Can do.

  One or both of the first electrode 708 and the second electrode 710 can be a transparent electrode. As the transparent electrode, indium oxide including tungsten oxide, indium zinc oxide including tungsten oxide, indium tin oxide including titanium oxide, indium tin oxide including titanium oxide, indium tin oxide including molybdenum, or the like is used. it can. Of course, indium tin oxide, indium zinc oxide, indium tin oxide added with silicon oxide, or the like can also be used.

At least one of the first electrode 708 and the second electrode 710 may be formed of a material that does not transmit light. For example, alkali metals such as Li and Cs, and alkaline earth metals such as Mg, Ca, and Sr, alloys containing these (Mg: Ag, Al: Li, Mg: In, etc.), and compounds thereof (CaF ₂ ) In addition, rare earth metals such as Yb and Er can be used.

  The fourth insulating layer 711 can be formed using a material similar to that of the third insulating layer 706.

  The light emitting element 752 includes an EL layer 709 and a first electrode 708 and a second electrode 710 that sandwich the EL layer 709. One of the first electrode 708 and the second electrode 710 corresponds to an anode, and the other corresponds to a cathode. When a voltage greater than the threshold voltage is applied between the anode and the cathode with a forward bias, the light-emitting element 752 emits light by current flowing from the anode to the cathode.

  The EL layer 709 includes a single layer or a plurality of layers. When composed of a plurality of layers, these layers can be classified into a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like from the viewpoint of carrier transport properties. Note that the boundaries between the layers are not necessarily clear, and there are cases where the materials constituting the layers are partially mixed and the interface is unclear. For each layer, an organic material or an inorganic material can be used. As the organic material, any of a high molecular weight material, a medium molecular weight material, and a low molecular weight material can be used.

  The EL layer 709 is preferably formed using a plurality of layers having different functions such as a hole injecting and transporting layer, a light emitting layer, and an electron injecting and transporting layer. The hole injecting and transporting layer is preferably formed of a composite material including a hole transporting organic compound material and an inorganic compound material that exhibits an electron accepting property with respect to the organic compound material. By adopting such a configuration, many hole carriers are generated in an organic compound that has essentially no intrinsic carrier, and extremely excellent hole injecting and transporting properties can be obtained. Due to this effect, the drive voltage can be made lower than in the prior art. In addition, since the hole injecting and transporting layer can be thickened without causing an increase in driving voltage, a short circuit of the light emitting element due to dust or the like can be suppressed.

  Examples of the hole transporting organic compound material include copper phthalocyanine (abbreviation: CuPc), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation). : MTDATA), 1,3,5-tris [N, N-di (m-tolyl) amino] benzene (abbreviation: m-MTDAB), N, N′-diphenyl-N, N′-bis (3-methyl) Phenyl) -1,1′-biphenyl-4,4′-diamine (abbreviation: TPD), 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4 , 4′-bis {N- [4-di (m-tolyl) amino] phenyl-N-phenylamino} biphenyl (abbreviation: DNTPD), and the like, but is not limited thereto.

  Examples of the inorganic compound material that exhibits electron acceptability include titanium oxide, zirconium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, and zinc oxide. Vanadium oxide, molybdenum oxide, tungsten oxide, and rhenium oxide are particularly preferable because they can be vacuum-deposited and are easy to handle.

The electron injecting and transporting layer is formed using an organic compound material having an electron transporting property. Specifically, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (2-methyl-8-quinolinolato) (4- Phenylphenolato) aluminum (abbreviation: BAlq), bathocuproin (abbreviation: BCP), 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD) ), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), and the like. There is no.

The EL layer is composed of 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 9,10-di (2-naphthyl) -2-tert-butylanthracene (abbreviation: t-BuDNA), 4,4 ′. -Bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), coumarin 30, coumarin 6, coumarin 545, coumarin 545T, rubrene, 2,5,8,11-tetra (tert-butyl) perylene (abbreviation: TBP) ), 9,10-diphenylanthracene (abbreviation: DPA), 5,12-diphenyltetracene, 4- (dicyanomethylene) -2-methyl- [p- (dimethylamino) styryl] -4H-pyran (abbreviation: DCM1) 4- (dicyanomethylene) -2-methyl-6- [2- (julolidin-9-yl) ethenyl] -4H-pyran (abbreviation: DC) M2) and the like. In addition, bis {2- [3 ′, 5′-bis (trifluoromethyl) phenyl] pyridinato-N, C ^{2 ′} } iridium (picolinate) (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), tris ( 2-phenylpyridinato-N, C2 ^′ ) iridium (abbreviation: Ir (ppy) ₃ ), bis (2-phenylpyridinato-N, C2 ^′ ) iridium (acetylacetonate) (abbreviation: Ir ( ppy) ₂ (acac)), bis [2- (2′-thienyl) pyridinato-N, C ^{3 ′} ] iridium (acetylacetonate) (abbreviation: Ir (thp) ₂ (acac)), bis (2-phenyl) A compound capable of emitting phosphorescence such as quinolinato-N, C ^{2 ′} ) iridium (acetylacetonate) (abbreviation: Ir (pq) ₂ (acac)) can also be used.

  Further, a triplet excitation material including a singlet excitation light emitting material and a metal complex may be used for the EL layer. For example, among red light emitting pixels, green light emitting pixels, and blue light emitting pixels, a red light emitting pixel having a relatively short luminance half time is formed of a triplet excitation light emitting material, and the other A singlet excited light emitting material is used. The triplet excited luminescent material has a feature that the light emission efficiency is good, so that less power is required to obtain the same luminance. That is, when applied to a red pixel, the amount of current flowing through the light emitting element can be reduced, so that reliability can be improved. As a reduction in power consumption, a red light-emitting pixel and a green light-emitting pixel may be formed using a triplet excitation light-emitting material, and a blue light-emitting pixel may be formed using a singlet excitation light-emitting material. By forming a green light-emitting element having high human visibility with a triplet excited light-emitting material, power consumption can be further reduced.

  The EL layer may be configured to perform color display by forming a light emitting layer having a different emission wavelength band for each pixel. Typically, a light emitting layer corresponding to each color of R (red), G (green), and B (blue) is formed. In this case as well, it is possible to improve the color purity and prevent mirror reflection (reflection) of the pixel portion by providing a filter that transmits light in the emission wavelength band on the light emission side of the pixel. Can do. By providing the filter, it is possible to omit a circularly polarizing plate that has been conventionally required, and the loss of light emitted from the light emitting layer can be eliminated. Furthermore, a change in color tone that occurs when the pixel portion (display screen) is viewed obliquely can be reduced.

  By combining the pixel having the configuration shown in FIG. 7 and the external light intensity detection means, the luminance of the display screen can be controlled by changing the light emission time of the light emitting element. Further, by controlling the light emission of the light emitting element by the external light intensity detecting means, the lighting time does not increase unnecessarily, so that the power consumption of the display panel can be reduced and the lifetime can be extended.

(Embodiment 7)
An optical sensor that detects the intensity of external light may be incorporated in a part of the display device. This optical sensor may be mounted on the display device as a component, or may be integrally formed on the display panel. In the case of being integrally formed on the display panel, the display surface can be used together as the light receiving surface of the photosensor, and an excellent design effect is exhibited. In other words, gradation control based on the intensity of external light can be performed without making the display device conscious of the fact that an optical sensor is attached.

  FIG. 8 is a diagram showing an embodiment in which a photosensor is integrally formed on a display panel. Note that FIG. 8 shows a case where a pixel is formed by a light-emitting element that emits light by electroluminescence and a TFT that controls the operation thereof.

  FIG. 8 illustrates a driving TFT 801 formed over a light-transmitting substrate 800, a first electrode 802 (pixel electrode) formed using a light-transmitting material, an EL layer 803, and a light-transmitting material. A second electrode 804 (counter electrode) is provided. The light emitting element 825 emits light upward (in the direction of the arrow). Then, on the insulating film 812 formed over the second electrode 804, a photoelectric conversion element 838 including a stack of a p-type layer 831, a substantially intrinsic i-type layer 832 and an n-type layer 833, and a p-type layer A p-layer side electrode 830 connected to the layer 831 and an n-layer side electrode 834 connected to the n-type layer 833 are provided.

  In this embodiment, a photoelectric conversion element 838 is used as an optical sensor element. The light-emitting element 825 and the photoelectric conversion element 838 are formed over the same substrate 800, and light emitted from the light-emitting element 825 forms an image and is visually recognized by the user. On the other hand, the photoelectric conversion element has a role of detecting external light and sending a detection signal to the controller. In this manner, the light emitting element and the optical sensor (photoelectric conversion element) can be manufactured on the same substrate, which can contribute to the downsizing of the set.

(Embodiment 8)
FIG. 9 illustrates a structure of a display panel including any one of Embodiments 1 to 7 or a combination thereof. A gate line driver circuit 901, a data line driver circuit 902, a counter electrode 903, and a connection terminal portion 905 are provided over a substrate 900. A seal region 904 is a region for bonding the substrate 900 and the counter substrate together. Therefore, when the substrate 900 and the counter substrate are attached to each other in the seal region, the gate line driver circuit 901, the data line driver circuit 902, and the counter electrode 903 are sealed by the substrate 900, the counter substrate, and the sealant.

  Note that a plurality of source lines extending in the column direction from the data line driver circuit 902 are arranged in the row direction below the counter electrode 903. A plurality of gate lines extending in the row direction from the gate line driving circuit 901 are arranged side by side in the column direction. In addition, a plurality of pixels including display elements are arranged in a matrix corresponding to the source lines and the gate lines.

  Note that the display element is an EL element (an organic EL element, an inorganic EL element, or an EL element including an organic substance and an inorganic substance), an element used in a field emission display (FED), or a SED (Surface-Conduction Electron-Emitter Display) which is a kind of FED. ), Liquid crystal display (LCD), plasma display (PDP), electronic paper display, digital micromirror device (DMD), piezoelectric ceramic display, and the like.

  A plurality of connection terminals are arranged in the connection terminal portion 905 formed on the substrate. These connection terminals are terminals for connecting to an external circuit in order to supply a signal or power input from the outside to a circuit formed on the substrate 900. The circuit formed over the substrate 900 is not only a circuit including a thin film transistor formed at the same time as a thin film transistor (also referred to as a TFT) included in a pixel, but also a circuit formed over an IC chip. A device mounted on top by COG (Chip On Glass) is also included. The IC chip refers to an integrated circuit formed on a substrate separated on the chip. In particular, as an IC chip, a single crystal silicon wafer is used as a substrate, a circuit is formed by element isolation or the like, and the single crystal silicon wafer is cut into an arbitrary shape. Further, for example, an FPC (Flexible Print Circuit) is electrically connected to the connection terminal portion 905 for connecting to an external circuit.

  Therefore, signals and power are supplied to the data line driver circuit 902 and the gate line driver circuit 901 through a wiring connected to the connection terminal, and power is supplied to the pixel electrode and the counter electrode.

  Here, in the display device of this embodiment, the data line driving circuit 902 is formed on the side opposite to the connection terminal portion 905 with the counter electrode 903 interposed therebetween. That is, the data line driver circuit 902 is not disposed between the connection terminal portion 905 and the counter electrode 903. Therefore, the connection terminal 906 to which the power supply potential input to the counter electrode 903 is input and the continuous wiring are connected to the counter electrode 903 through the contact hole 907 without straddling the data line driver circuit.

  In other words, according to this configuration, since the counter electrode 903 does not cross over the data line driver circuit 902, it is possible to prevent the generation of parasitic capacitance caused by the counter electrode 903 overlapping the data line driver circuit 902.

  Further, when the connection terminal 906 and the counter electrode 903 are connected through the data line driving circuit 902 by the multilayer wiring structure, an increase in contact resistance between the wirings is caused. However, according to this configuration, since the connection terminal 906 and the counter electrode 903 can be connected without a multilayer wiring structure, the resistance can be reduced. In addition, since the distance between the connection terminal 906 and the counter electrode 903 is short, wiring resistance can be reduced.

  Next, the connection between the connection terminal 906 and the counter electrode 903 will be described in more detail with reference to a cross-sectional view taken along the line ab in FIG. FIG. 10A is a diagram illustrating an example of a cross section between the line ab in FIG.

  A base layer 951 is provided over the substrate 900. As the substrate 900, a glass substrate, a quartz substrate, a plastic substrate, an insulating substrate such as a ceramic substrate, a metal substrate, a semiconductor substrate, or the like can be used.

The base layer 951 can be formed by a CVD method or a sputtering method. For example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like formed by a CVD method using SiH ₄ , N ₂ O, or NH ₃ as a raw material can be used. Moreover, you may use these lamination | stacking. Note that the base layer 951 is provided to prevent impurities from diffusing from the substrate 900 to the semiconductor layer, and the base layer 951 is not necessarily provided when a glass substrate or a quartz substrate is used as the substrate 900.

  A gate insulating film 952 is provided over the base layer 951. As the gate insulating film 952, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or the like formed by a CVD method or a sputtering method can be used.

  An interlayer insulating film is provided over the gate insulating film 952. The interlayer insulating film has a lower insulating film 953 and an upper insulating film 954. As the lower insulating film 953, for example, an inorganic insulating film can be used. As the inorganic insulating film, a silicon nitride film, a silicon oxide film, a silicon oxynitride film, or a film in which these are stacked can be used. In addition, as the upper insulating film, an inorganic insulating film or a resin film can be applied. As the inorganic insulating film, those described above can be used, and as the resin film, polyimide, polyamide, acrylic, polyimide amide, epoxy, or the like can be used.

  In addition, a wiring 955 and a wiring 956 are provided over the interlayer insulating film. Note that the wiring 955 and the wiring 956 are formed using conductive films of the same material in the same layer. Examples of these materials include a titanium (Ti) film, an aluminum (Al) film, a copper (Cu) film, and an aluminum film containing Ti. Can be used. More preferably, the wiring 955 and the wiring 956 have a three-layer structure in which a titanium (Ti) film is formed as a lower layer, an aluminum (Al) film is formed thereon, and a titanium (Ti) film is formed thereon.

  Note that the wiring 955 corresponds to the wiring of the connection terminal 906 in FIG. A wiring 956 corresponds to the wiring in the seal region 904. The wiring in the seal region 904 formed of the same material in this layer includes a wiring in contact with the impurity region of the transistor.

  An insulating layer 957 is formed over the wiring 956 and the wiring 955. For example, as the insulating layer 957, a positive photosensitive acrylic resin film can be used.

  Further, an EL layer 958 is provided over the insulating layer 957. Further, a counter electrode 903 and a connection electrode 959 are provided over the EL layer 958. A contact hole is formed in the insulating layer 957, and the counter electrode 903 is connected to the wiring 955 through the contact hole. The connection electrode 959 is also connected to the wiring 955. Therefore, the connection terminal 906 includes a part of the wiring 955 and the connection electrode 959, and the connection electrode 959 corresponds to a connection pad of the connection terminal 906.

  The configuration shown in FIG. 9 is particularly preferably applied to a display panel having a screen size of about 1 to 3 inches.

  Note that the above-described cross-sectional view 10A is an example, and the present invention is not limited to this. Another structure is shown in FIG. Note that the same reference numerals are used for portions common to FIG. 10A, and description thereof is omitted.

  The structure in FIG. 10B includes a wiring 960 over the gate insulating film 952. Note that the wiring 960 corresponds to a part of the connection terminal 906 in FIG. The wiring in the seal region formed of the same material in the same layer as the wiring 960 includes what constitutes the gate electrode of the transistor.

  An interlayer insulating film (a lower insulating film 953 and an upper insulating film 954) is provided over the wiring 960. A wiring 956 and a wiring 961 are provided over the upper insulating film 954, and the wiring 961 is connected to the wiring 960 through a contact hole. A wiring 956 corresponds to the wiring in the seal region 904. The wiring in the seal region 904 formed of the same material in this layer includes a wiring in contact with the impurity region of the transistor.

  Further, an insulating layer 957 is provided over the wiring 956, the wiring 961, and the upper insulating film 954. An EL layer 958 is formed over the insulating layer 957 and in the seal region. A counter electrode 903 is formed over the EL layer 958 and the insulating layer 957 in the seal region. A connection electrode 959 is formed over the insulating layer 957 in the connection terminal portion. The counter electrode 903 in the seal region is connected to the wiring 961 through a contact hole, and the connection electrode 959 in the connection terminal portion is connected to the wiring 960 through a contact hole.

  At this time, the connection terminal 906 includes a part of the wiring 960 and the connection electrode 959, and the connection electrode 959 corresponds to a connection pad of the connection terminal 906.

  The structure of the display panel shown in FIGS. 9 and 10 has a pixel region formed of an EL element formed over a substrate having an insulating property. The upper electrode, which is one electrode of the EL element, is a terminal group provided on the side opposite to the data line driving circuit, and is electrically connected to one terminal disposed at the center or near the center. . With such a configuration, the influence of resistance loss due to the upper electrode or its lead-out wiring is not biased to one side of the display panel, so that unevenness in luminance in the pixel region can be reduced.

  A schematic diagram of the second configuration of the present embodiment is shown in FIG. Also in the configuration of FIG. 11, portions common to the configuration of FIG. 9 are denoted by common reference numerals, and description thereof is omitted. Also in this configuration, the gate line driver circuit 901, the data line driver circuit 902, the counter electrode 903, and the connection terminal portion 905 are provided over the substrate 900. A seal region 904 is a region for bonding the substrate 900 and the counter substrate together. Therefore, when the substrate 900 and the counter substrate are attached to each other in the seal region, the gate line driver circuit 901, the data line driver circuit 902, and the counter electrode 903 are sealed by the substrate 900, the counter substrate, and the sealant.

  In addition, this structure has an auxiliary wiring on the counter electrode. The auxiliary wiring includes a first wide wiring 908, a second wide wiring 909, and a plurality of branch wirings 910, which are formed of a continuous conductive film. The first wide wiring 908 is connected to the connection terminal 906 and a continuous wiring through a contact hole 907. Note that the first wide wiring 908 is preferably wider than the connection terminal 906 and the continuous wiring. The second wide wiring 909 is preferably approximately equal to the length in the row direction in which the pixels of the pixel portion are arranged. The branch wiring 910 preferably has the number of pixel columns.

  Next, a cross-sectional view taken along line ab in FIG. 11 is shown in FIG. Note that portions common to the configuration in FIG. 10 are denoted by common reference numerals, and description thereof is omitted. In this configuration, the first wide wiring 908 is provided on the counter electrode 903.

  Note that the structure illustrated in FIG. 12A is an example, and the present invention is not limited to this. Therefore, a configuration as shown in FIG. In FIG. 12B, the first wide wiring 908 formed over the counter electrode 903 is in direct contact with the wiring 955 through the contact hole, whereby the counter electrode 903 and the connection terminal 906 are electrically connected.

  Still another structure is shown in FIG. In the case of FIG. 12C, the first wide wiring 908 is provided over the EL layer 958, and the counter electrode 903 is formed over the first wide wiring 908.

  FIG. 15 shows an example of a cross section between lines cd in FIG. 11 in the case of the configuration as shown in FIG. 12 (A) or FIG. B (B). Note that portions common to those in FIGS. 12A and 12B are denoted by common reference numerals, and description thereof is omitted. Also in FIG. 15, a base layer 951 is provided over a substrate 900, a gate insulating film 952 is further provided thereon, a lower insulating film 953 is further provided thereon, and an upper insulating film 954 is further provided thereon. Have.

  An insulating layer 957 is provided over the upper insulating film 954, and the EL layers 958 formed over the insulating layer 957 are isolated from each other on the insulating layer 957.

  Further, a counter electrode 903 is provided over the insulating layer 957 and the EL layer 958. In addition, a branch wiring 910 is provided above the insulating layer 957 with a counter electrode 903 interposed therebetween. Therefore, this structure is particularly suitable for the case where top emission is used in which a conductive film such as ITO is used for the counter electrode and light is extracted from the side opposite to the substrate 900. This is because the resistance can be reduced by connecting the counter electrode 903 to the branch wiring 910. This is because the branch wiring 910 is over the insulating layer 957 and thus does not hinder light extraction.

  The configuration shown in FIG. 11 is particularly preferably applied to a display panel having a screen size of about 3 inches to 10 inches.

  On the other hand, FIG. 16 is a preferred embodiment when applied to a display panel having a screen size of about 10 inches to 40 inches. With respect to the structure of FIG. 11, the gate line driver circuit 901 is provided on both sides of the display region, and the data line driver circuit and the connection terminal portion 905 are arranged on the same side. The auxiliary wiring includes a first first wide wiring 908, a second wide wiring 909, and a plurality of branch wirings 910. The lead wiring is provided on the opposite side to the data line driving circuit. The connection terminal portion 905 is configured separately. With such a configuration, the distance until the lead-out wiring reaches the end of the substrate 900 can be shortened, and resistance loss can be reduced.

  A schematic diagram of the third configuration of the present embodiment is shown in FIG. Also in the configuration of FIG. 13, common portions with FIG. 9 are denoted by common reference numerals and description thereof is omitted. Also in this configuration, the gate line driver circuit 901, the data line driver circuit 902, the counter electrode 903, the connection terminal portion 905, the first IC chip 920, the second IC chip 921, and the optical sensor chip 922 are provided over the substrate 900. . A seal region 904 is a region for bonding the substrate 900 and the counter substrate together. Therefore, when the substrate 900 and the counter substrate are attached to each other in the seal region, the gate line driver circuit 901, the data line driver circuit 902, the counter electrode 903, the first IC chip 920, The second IC chip 921 and the optical sensor chip 922 are encapsulated. As shown in Embodiment Mode 1, the optical sensor chip 922 constitutes part of a function of detecting the intensity of external light and controlling the number of gradations in display. One or both of the first IC chip 920 and the second IC chip 921 may function as a controller.

  In this configuration, the wiring extending from the connection terminal of the connection terminal portion 905 is electrically connected to the IC chip. That is, each connection terminal is electrically connected to any of the first IC chip 920, the second IC chip 921, and the optical sensor chip 922, respectively. The first IC chip 920, the second IC chip 921, and the optical sensor chip 922 are connected to the data line driver circuit 902, the gate line driver circuit 901, the counter electrode 903, and the like by a plurality of wirings. For example, the first IC chip 920 and the counter electrode 903 are electrically connected through a contact hole 907 by a wiring 925. Note that the number and arrangement of the IC chips shown in this configuration is an example, and the present invention is not limited to this. For example, mounting on the substrate 900 is not limited to an IC chip, and may be a chip capacitor or a multilayer ceramic coil.

  Subsequently, FIG. 14 shows a cross section between the line ab in FIG. 13 in the case of a display panel in which the substrate 900 and the counter substrate are bonded to each other with a sealant in the seal region 904. Note that the cross-sectional view shown in FIG. 14 has the same reference numerals as those in FIG. 10, and description thereof is omitted.

  In this structure, a wiring 955 and a wiring 925 are provided over the upper insulating film 954. The wiring 955 is formed across the seal region 904. The wiring 925 is formed in the seal region 904.

  An insulating layer 957 is provided over the wiring 955, and the connection electrode 959 formed over the insulating layer 957 is electrically connected through a contact hole. In addition, an insulating layer 957 is formed so as to cover an end portion of the wiring 925. An EL layer 958 is provided over the insulating layer 957 in the seal region 904, and a counter electrode 903 is provided thereover.

  In the seal region 904, the first IC chip 920 is provided over the upper insulating film 954, the wiring 955, and the wiring 925, and the first IC chip 920 is electrically connected to the wiring 955 and the wiring 925. .

  In addition, in the seal region 904, a sealant 924 is provided over the insulating layer 957, and the counter substrate 923 and the substrate 900 are attached to each other by the sealant. Note that the present invention is not limited to the configuration of the display device described above. In this embodiment, the display device includes a module and a display panel body to which the FPC is connected.

  The configuration shown in FIG. 13 is particularly preferably applied to a display panel having a screen size of about 1 to 3 inches.

(Embodiment 9)
FIG. 17A shows a module in which the display panel 1 and the printed board 2 are combined. The display panel 1 includes a pixel portion 3 in which a light emitting element is provided in each pixel, a first scanning line driving circuit 4 and a second scanning line driving circuit 5, and signal line driving for supplying a video signal to a selected pixel. A circuit 6 is provided. The pixel unit 3 has a configuration similar to that of the sixth embodiment.

  The printed circuit board 2 includes an optical sensor 29, a controller 7, a CPU 8 (central processing unit), a memory 9, a power supply circuit 10, an audio processing circuit 11, a transmission / reception circuit 12, and the like. The printed board 2 and the display panel 1 are connected by a flexible board 13 (FPC). The flexible substrate 13 may be provided with a capacitor element, a buffer circuit, and the like so as to prevent noise from being applied to the power supply voltage and the signal and the rise of the signal from being slowed down. The controller 7, the audio processing circuit 11, the memory 9, the CPU 8, and the like can be mounted on the display panel 1 using a COG (Chip on Glass) method. The scale of the printed circuit board 2 can be reduced by the COG method.

  Various control signals are input and output via an interface 14 (I / F unit) provided on the printed circuit board 2. An antenna port 15 for transmitting and receiving signals to and from the antenna is provided on the printed board 2.

  FIG. 17B shows a block diagram of the module shown in FIG. This module includes a VRAM 16 (video RAM), a DRAM 17 (dynamic RAM), a flash memory 18 and the like as the memory 9. The VRAM 16 stores image data to be displayed on the panel, the DRAM 17 stores image data or audio data, and the flash memory stores various programs.

  The CPU 8 includes a control signal generation circuit 20, a decoder 21, a register 22, a calculation circuit 23, a RAM 24 (random access memory), an interface 19 for the CPU 8, and the like. Various signals input to the CPU 8 via the interface 19 are once held in the register 22 and then input to the arithmetic circuit 23, the decoder 21, and the like. The arithmetic circuit 23 performs an operation based on the input signal and designates a place where various commands are sent. On the other hand, the signal input to the decoder 21 is decoded and input to the control signal generation circuit 20. The control signal generation circuit 20 generates a signal including various instructions based on the input signal, and a location designated in the arithmetic circuit 23, specifically, the memory 9, the transmission / reception circuit 12, the sound processing circuit 11, the controller 7, etc. Send to.

  The memory 9, the transmission / reception circuit 12, the sound processing circuit 11, the optical sensor 29, and the controller 7 operate according to the received commands. The operation will be briefly described below.

  A signal input from the input unit 25 is sent to the CPU 8 mounted on the printed circuit board 2 via the interface 14. The control signal generation circuit 20 converts the image data stored in the VRAM 16 into a predetermined format in accordance with a signal sent from the input means 25 such as a pointing device or a keyboard, and sends it to the controller 7.

  The controller 7 receives the signal from the optical sensor 29 and changes the number of gradations. When the external light intensity is high, the number of gradations is decreased, and when it is weak, the number of gradations is increased. Furthermore, data processing is performed on a signal including image data sent from the CPU 8 in accordance with the specifications of the panel, and the signal is supplied to the display panel 1. Further, the controller 7 generates an Hsync signal, a Vsync signal, a clock signal CLK, an AC voltage (AC Cont), and a switching signal L / R based on the power supply voltage input from the power supply circuit 10 and various signals input from the CPU 8. It is generated and supplied to the display panel 1.

  In the transmission / reception circuit 12, a signal transmitted / received as a radio wave is processed by the antenna 28, and specifically, a high frequency such as an isolator, a band pass filter, a VCO (Voltage Controlled Oscillator), an LPF (Low Pass Filter), a coupler, and a balun. Includes circuitry. A signal including audio information among signals transmitted and received in the transmission / reception circuit 12 is sent to the audio processing circuit 11 in accordance with a command from the CPU 8.

  A signal including audio information sent in accordance with an instruction from the CPU 8 is demodulated into an audio signal in the audio processing circuit 11 and sent to the speaker 27. The audio signal sent from the microphone 26 is modulated by the audio processing circuit 11 and sent to the transmission / reception circuit 12 in accordance with a command from the CPU 8.

  By combining the pixel having the configuration shown in FIG. 17 and the external light intensity detection means, the luminance of the display screen can be controlled by changing the light emission time of the light emitting element. Further, by controlling the light emission of the light emitting element by the external light intensity detecting means, the lighting time does not increase unnecessarily, so that the power consumption of the display panel can be reduced and the lifetime can be extended.

(Embodiment 10)
This embodiment mode shows an example of a mobile phone as an electric appliance according to the present invention.

  A cellular phone 1000 illustrated in FIG. 18 includes a main body (A) 1001 provided with operation switches 1004, a microphone 1005, and the like, a main body provided with a display panel (A) 1008, a display panel (B) 1009, a speaker 1006, and the like. (B) 1002 is connected by a hinge 1010 so that it can be opened and closed. The display panel (A) 1008 and the display panel (B) 1009 are housed in the housing 1003 of the main body (B) 1002 together with the circuit board 1007. The pixel portions of the display panel (A) 1008 and the display panel (B) 1009 are arranged so as to be visible from an opening window formed in the housing 1003. The circuit board 1007 is provided with a signal processing circuit 1011 and an optical sensor 1050. This optical sensor 1050 is for measuring the intensity of external light.

  In the display panel (A) 1008 and the display panel (B) 1009, specifications such as the number of pixels can be set as appropriate in accordance with the function of the mobile phone 1000. For example, the display panel (A) 1008 can be combined as a main screen and the display panel (B) 1009 can be combined as a sub-screen.

  The display panel (A) 1008 can be a high-definition color display screen for displaying characters and images, and the display panel (B) 1009 can be a monochrome information display screen for displaying character information. In particular, when the display panel (B) 1009 is an active matrix type and has high definition, various character information can be displayed and the information display density per screen can be improved. For example, the display panel (A) 1008 is 2 to 2.5 inches with 64 gradations and 260,000 colors of QVGA (320 dots × 240 dots), and the display panel (B) 1009 is monochrome with 2 gradations. As a high-definition panel of 8 gradations, 180 ppi to 220 ppi, it is possible to display alphabets, hiragana, katakana, kanji and arabic characters.

  One or both of the display panel (A) 1008 and the display panel (B) 1009 has a structure similar to that in Embodiments 1 to 9. In other words, the display panel (A) 1008 and the display panel (B) 1009 are provided by including a light sensor 1050 and a signal processing circuit 1011 and providing gradation number control means for changing the number of gradations according to the external light intensity. The visibility of information displayed on one or both display screens can be improved. In addition, power consumption can be reduced by adding a function of controlling the number of gradations according to the external light intensity to the mobile phone. Thereby, it can be used continuously for a long time. In addition, since the battery can be reduced in size, the mobile phone can be reduced in weight.

  Such a cellular phone 1000 can perform display by various driving methods. For example, there is a time gradation method as one example. The time gradation is to display the gradation by changing the lighting time of the light emitting element that emits light with a certain luminance. For example, the lighting rate is 100% if all the frames are lit during one frame period. Further, if the lighting is performed for half of the period of one frame, the lighting rate is 50%. If the frame frequency is high to some extent, generally, if it is 60 Hz or higher, blinking cannot be recognized by the human eye, and it is recognized as a halftone. In this way. It is possible to express gradation by changing the lighting rate.

  In FIG. 19A, time is taken on the horizontal axis, and the vertical axis of the pixels on the display screen is taken on the vertical axis. In this example, the display screen is written in order from the top, so that the display is delayed. In the example of FIG. 19A, writing is performed in order from the top, but the present invention is not limited to this. In the following, description will be made by taking 4 bits as an example.

  In FIG. 19A, one frame is divided into four subframes (Ts1, Ts2, Ts3, Ts4). The ratio of the lengths of the respective subframes is Ts1: Ts2: Ts3: Ts4 = 8: 4: 2: 1. By combining these sub-frames, it is possible to set the length of the lighting period from 0 to 15. Thus, gradation can be expressed by dividing one frame into power-of-two subframes. Further, since the lighting period is short at Ts4, it is necessary to turn off the upper half before the writing of the lower half of the screen is completed, and writing and erasing are performed in parallel.

  FIG. 19B shows the gradation expression in a time segment different from that in FIG. In the gradation expression means of FIG. 19A, when the upper bits change, a problem called pseudo contour occurs. This is an illusion that when the human eye sees the seventh gradation and the eighth gradation alternately, the image looks different from the original gradation. Therefore, in FIG. 19B, the upper bits are divided to reduce the above-described pseudo contour phenomenon. Specifically, the most significant bit (here, Ts1) is divided into four and arranged in one frame. The second bit (here, Ts2) is divided into two and arranged in one frame. In this way, bits that are long in time are divided to reduce pseudo contours.

  In FIG. 20A, subframes are divided at equal intervals instead of a power of two so that pseudo contours do not occur. In this method, since there is no large bit break, pseudo contour does not occur, but the gradation itself becomes rough. Therefore, it is necessary to perform gradation complementation using FRC (frame rate control) or dither.

  FIG. 20B shows a case where only binary values are performed. In this case, since only one subframe exists in one frame, the number of rewrites is once per frame, and the power consumption of the controller and driver can be reduced. In a cellular phone, when mainly displaying character information such as e-mail (mail mode), the number of gradations is lower than when displaying moving images and still images, and thus display with priority on power consumption is possible. By combining such display with the above-described FIG. 19A, FIG. 19B, FIG. 20A, and the like, a case where a large number of gradations is necessary and a case where a small number of gradations are sufficient are selectively used. Reduction of power consumption becomes possible.

  FIG. 20C represents four gradations, and display is performed by writing three times in one frame period. This can be applied to a case where it is better to increase the number of gradations than a case where a still image such as a comic is displayed and character information is displayed. The number of gradations may be set within a range of about 4 to 16 gradations.

  In this manner, as described in Embodiments 1 to 9, a method of changing the number of display gradations in accordance with the external light intensity can be applied to a mobile phone. In this case, for example, a driving method including a natural image or moving image mode with 16 gradations or more, a still image mode for displaying with 4 to 16 gradations, and a mail mode with 2 to 8 gradations is combined. As a result, power consumption of the mobile phone can be reduced.

  The mobile phone according to the present embodiment can be transformed into various modes according to the function and application. For example, a mobile phone with a camera may be provided by incorporating an image sensor at the hinge 1010. In addition, even when the operation switches 1004, the display panel (A) 1008, and the display panel (B) 1009 are housed in one housing, the above-described effects can be obtained. Moreover, even if the configuration of the present embodiment is applied to an information display terminal having a plurality of display units, the same effect can be obtained. In addition, the configuration according to this embodiment is not limited to a mobile phone, and can be widely applied to information terminals represented by computers and input digital assistants (PDAs) provided with input means such as a display panel and operation switches. it can.

  FIG. 21 illustrates a computer, which includes a main body 1201, a housing 1202, a display unit 1203, a keyboard 1204, an external connection port 1205, a pointing mouse 1206, and an optical sensor 1208. According to the present invention, a computer with high visibility can be configured even under strong external light, which is easy to use for the user and can reduce eye fatigue.

(Embodiment 11)
FIG. 22 shows an aspect of the vehicle according to the present invention. This vehicle has a sensor that detects the external light intensity, and displays a low gradation when the external light intensity is high, displays a high gradation when the external light intensity is low, and when the external light intensity is between them. A display device for displaying the intermediate gradation is included.

  FIG. 22A shows the driver's seat of the vehicle, and FIG. 22B shows the state viewed from the top. The display panel 1103 is a console panel 1105 and is provided on the right hand of the handle 1102 (left hand when using the left handle). The size of the display panel 1103 is not limited, but a vertically long 3.5-inch panel or the like is a preferable mode as a size for effectively displaying information without obstructing the driver's visual field. The display panel 1103 may be disposed obliquely at an angle of 5 degrees to 30 degrees toward the driver. Such a display panel 1103 is preferably the one shown in FIG.

  The display panel 1103 detects the intensity of external light by optical sensors 1104 provided at one or a plurality of locations on the console panel 1105. The control device 1106 controls the display gradation number of the display panel 1103 in accordance with the external light intensity. This display panel 1103 can display information useful to the driver, such as a map, traffic jam information, and weather forecast. That is, a navigation system can be constructed in combination with a GPS system. In this case, as described in Embodiment 1, the information displayed on the display panel 1103 is visually recognized even in a situation where direct sunlight is inserted into the vehicle 1101 and the display panel 1103 is exposed to sunlight. Can do.

(Appendix)
As described above, according to the present invention, the following modes can be derived.

  A display unit; a controller that supplies a video signal to the display unit; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. The controller changes the number of gradations of the video signal. And a gradation output selection unit that selects the number of gradations to be output to the display panel according to the output of the optical sensor.

  A display unit; a controller that supplies a video signal to the display unit; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. The controller changes the number of gradations of the video signal. And a gradation output selection unit that selects the number of gradations to be output to the display panel in accordance with the output of the optical sensor. A display device that displays a high gradation when the intensity is low and displays an intermediate gradation when the external light intensity is between them.

  A display unit; a controller that supplies a video signal to the display unit; a memory unit that stores the video signal; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. A gradation conversion unit that changes the number of gradations of the video signal and stores it in the memory unit, and a gradation that reads out the video signal output to the display panel in accordance with the output of the optical sensor from the memory unit and transmits it to the display unit A display device including an output selection unit.

  A display unit; a controller that supplies a video signal to the display unit; a memory unit that stores the video signal; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. A gradation converter for changing the number of gradations of the video signal and storing it in the memory unit; and a gradation output for reading out the video signal to be output to the display panel according to the output of the optical sensor from the memory unit and transmitting it to the display unit A low gradation display when the external light intensity is high, a high gradation display when the external light intensity is low, and an intermediate gradation display when the external light intensity is between them. Display device to perform.

  A display unit; a controller that supplies a video signal to the display unit; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. A display device driving method in which low gradation display is performed when the light intensity is high, high gradation display is performed when the external light intensity is low, and intermediate gradation display is performed when the external light intensity is between them.

  A display unit; a controller that supplies a video signal to the display unit; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. The display mode is switched between display and moving image display, and according to the output of the light sensor, low gradation display is performed when the external light intensity is high, and high gradation display is performed when the external light intensity is low. A driving method of a display device that displays an intermediate gray level when is between them.

  A display unit; a controller that supplies a video signal to the display unit; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. The display mode is switched between the display mode and the moving image display, and according to the output of the optical sensor, the text display mode displays from 2 to 8 gradations, and the picture display mode displays 4 images with a small number of colors. Display device driving method for performing display by switching from 64 gradations to 1024 gradations in a video mode in which display is performed from gradations to 16 gradations and a natural image having a large number of colors including moving images is displayed .

  A display unit; a controller that supplies a video signal to the display unit; and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity. The display mode is switched between the display mode and the moving image display, and according to the output of the optical sensor, when the external light intensity is 100,000 lux, two gradations are displayed, and the external light intensity is from 10,000 lux to 100,000. Display from 2 to 8 gradations at 000 lux, display from 4 to 16 gradations when the external light intensity is from 1,000 lux to 10,000 lux, and an external light intensity of 100 A driving method of a display device that performs display from 16 gradations to 64 gradations when lux is 1,000 lux, and displays from 64 gradations to 1024 gradations when the external light intensity is less than 100 lux.

  In this driving method of the display device, the optical sensor receives external light, and in strong external light intensity under sunny daylight sunlight, character information with a lower gradation than the external light intensity in a fluorescent lamp illumination indoor, Includes those that display still images.

  In the driving method of this display device, in an environment under sunny daylight sunlight or cloudy daylight sunlight, 2 to 8 gradations, under sunlight 1 hour before sunny day or under sunlight 1 hour after cloudy daylight, Or the thing which displays from 4 gradations to 16 gradations in the fluorescent lamp illumination indoor environment is included.

FIG. 6 illustrates a structure of a display device according to the present invention. The figure which shows the aspect of the mobile telephone which can switch a display mode according to external light intensity | strength. FIG. 6 illustrates a configuration example of a pixel in the display device described in Embodiment 1; 2 is a diagram illustrating an example of a system that creates an image in which light and darkness of a signal illustrated in Embodiment 1 is reversed. FIG. FIG. 11 illustrates one embodiment of a mobile phone using a double-sided light emitting display panel. FIG. 6 shows a concept of a double-sided light emitting display panel used for a mobile phone in Embodiment 4; FIG. 6 illustrates one embodiment of a pixel structure of the display device described in any of Embodiments 1 to 5. The figure which shows the one aspect | mode which forms an optical sensor integrally on a display panel. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. FIG. 5 shows a structure of a display region, a driver circuit, and a terminal portion in a display panel according to the present invention. The figure which shows the module which combined the display panel and the printed wiring board. The figure which shows the aspect of the mobile telephone which can switch a display mode according to external light intensity | strength. 10A and 10B illustrate a method for driving a mobile phone according to Embodiment 10. 10A and 10B illustrate a method for driving a mobile phone according to Embodiment 10. The figure which shows the aspect of the computer which can switch a display mode according to external light intensity | strength. The figure which shows the aspect of the vehicle containing the display panel which can switch a display mode according to external light intensity | strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display panel 2 Printed circuit board 3 Pixel part 4 1st scanning line drive circuit 5 2nd scanning line drive circuit 6 Signal line drive circuit 7 Controller 8 CPU
9 Memory 10 Power supply circuit 11 Audio processing circuit 12 Transmission / reception circuit 13 Flexible substrate 14 Interface 15 Antenna port 16 VRAM
17 DRAM
18 Flash memory 19 Interface 20 Control signal generation circuit 21 Decoder 22 Register 23 Arithmetic circuit 24 RAM
25 Input means 26 Microphone 27 Speaker 28 Antenna 29 Photo sensor 100 Display device 101 Controller 102 Memory 103 Photo sensor 104 Amplifier 105 Power supply 106 Display panel 201 First housing 202 Second housing 203 Display screen 204 Speaker 205 Antenna 206 Hinge 207 Keyboard 208 Microphone 209 Optical sensor 301 Switching TFT
302 Driving TFT
303 Light Emitting Element 304 Storage Capacitance S1 Source Signal Line V1 Power Supply Line G1 Gate Signal Line SF1 Subframe Ta1 Address Period Ts1 Sustain Period 401 Display Panel 402 Control Circuit 403 Switch 404 First Memory 405 Second Memory 406 Video Signal Selection Switch 407 switch 501 first housing 502 second housing 503 first display screen 504 second display screen 505 third display screen 506 speaker 507 antenna 508 hinge 509 keyboard 510 microphone 511 battery 601 transparent substrate 602 transparent substrate 603 Electrode 604 Electrode 605 Electrode 606 EL layer 607 EL layer 608 EL layer 609 Electrode 610 Color filter 611 Color filter 612 Color filter 700 Substrate 701 Blocking layer 7 02 Semiconductor layer 703 First insulating layer 704 Gate electrode 705 Second insulating layer 706 Third insulating layer 707 Wiring 708 First electrode 709 EL layer 710 Second electrode 711 Fourth insulating layer 712 Semiconductor layer 750 TFT
751 Capacitor 752 Light emitting element 800 Substrate 801 Driving TFT
802 First electrode 803 EL layer 804 Second electrode 812 Insulating film 825 Light emitting element 830 p layer side electrode 831 p type layer 832 i type layer 833 n type layer 834 n layer side electrode 838 Photoelectric conversion element 900 Substrate 901 Gate line Drive circuit 902 Data line drive circuit 903 Counter electrode 904 Seal region 905 Connection terminal portion 906 Connection terminal 907 Contact hole 908 First wide wiring 909 Second wide wiring 910 Branch wiring 920 First IC chip 921 Second IC chip 922 Photosensor chip 923 Counter substrate 924 Sealing material 925 Wiring 951 Underlayer 952 Gate insulating film 953 Lower insulating film 954 Upper insulating film 955 Wiring 956 Wiring 957 Insulating layer 958 EL layer 959 Connection electrode 960 Wiring 961 Wiring 1001 Main body (A)
1002 Body (B)
1003 Case 1004 Operation switches 1005 Microphone 1006 Speaker 1007 Circuit board 1008 Display panel (A)
1009 Display panel (B)
1010 Hinge 1011 Signal processing circuit 1050 Optical sensor 1201 Main body 1202 Case 1203 Display unit 1204 Keyboard 1205 External connection port 1206 Pointing mouse 1207 Audio output unit 1208 Optical sensor 1101 Vehicle 1102 Handle 1103 Display panel 1104 Optical sensor 1105 Console panel 1106 Control device

Claims (10)

A display unit, a controller that supplies a video signal to the display unit, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
The controller includes a gradation conversion unit that changes the number of gradations of the video signal, and a gradation output selection unit that selects the number of gradations to be output to the display panel according to the output of the photosensor. Characteristic display device. A display unit, a controller that supplies a video signal to the display unit, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
The controller includes a gradation conversion unit that changes the number of gradations of the video signal, and a gradation output selection unit that selects the number of gradations to be output to the display panel according to the output of the photosensor,
When external light intensity is high, low gradation display is performed, when external light intensity is low, high gradation display is performed, and when external light intensity is between them, intermediate gradation display is performed. Display device. A display unit, a controller that supplies a video signal to the display unit, a memory unit that stores the video signal, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
The controller includes a gradation conversion unit that changes the number of gradations of a video signal and stores the change in the memory unit;
A display device, comprising: a gradation output selection unit that reads out a video signal to be output to a display panel in accordance with an output of the optical sensor from the memory unit and transmits the video signal to the display unit. A display unit, a controller that supplies a video signal to the display unit, a memory unit that stores the video signal, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
The controller includes a gradation conversion unit that changes the number of gradations of a video signal and stores the change in the memory unit;
A gradation output selection unit that reads out a video signal to be output to the display panel in accordance with the output of the photosensor from the memory unit and transmits the read signal to the display unit;
When external light intensity is high, low gradation display is performed, when external light intensity is low, high gradation display is performed, and when external light intensity is between them, intermediate gradation display is performed. Display device. A display unit, a controller that supplies a video signal to the display unit, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
Depending on the output of the light sensor, a low gradation display is performed when the external light intensity is high, a high gradation display is performed when the external light intensity is low, and an intermediate gradation when the external light intensity is between them. A display device driving method, characterized by: A display unit, a controller that supplies a video signal to the display unit, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
In accordance with the video signal, the display mode is switched between text display, still image display, and video display,
Depending on the output of the light sensor, a low gradation display is performed when the external light intensity is high, a high gradation display is performed when the external light intensity is low, and an intermediate gradation when the external light intensity is between them. A display device driving method, characterized by: A display unit, a controller that supplies a video signal to the display unit, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
In accordance with the video signal, the display mode is switched between text display, still image display, and video display,
Depending on the output of the photosensor, the text display mode displays from 2 to 8 gradations,
In the picture display mode for displaying an image with a small number of colors, display is performed from 4 to 16 gradations, and in the video mode for displaying a natural image with a large number of colors including moving images, display is performed from 64 to 1024 gradations. A display device driving method, wherein display is performed by switching to perform the above. A display unit, a controller that supplies a video signal to the display unit, and an optical sensor that receives external light and outputs a signal corresponding to the external light intensity,
In accordance with the video signal, the display mode is switched between text display, still image display, and video display,
Depending on the output of the light sensor,
When the external light intensity is 100,000 lux, display with 2 gradations,
When the external light intensity is 10,000 lux to 100,000 lux, display from 2 to 8 tones,
When the external light intensity is 1,000 lux to 10,000 lux, display from 4 to 16 tones,
When the external light intensity is 100 lux to 1,000 lux, display from 16 to 64 gradations,
A display device driving method, wherein display is performed from 64 gradations to 1024 gradations when the external light intensity is less than 100 lux. In any one of Claims 5 thru | or 8,
The light sensor receives external light, and displays character information and still images at a lower gradation compared to the external light intensity indoors in a fluorescent lamp illumination in a strong external light intensity under sunny daylight. A display device driving method. In any one of Claims 5 thru | or 8,
The light sensor receives outside light, and has 2 to 8 gradations in sunny daylight or cloudy daylight, 1 hour before sunny daylight or 1 hour after cloudy daylight A display device that performs display of 4 to 16 gradations in sunlight or in an indoor environment illuminated by a fluorescent lamp.

Images