JP2005038838A - Light emitting device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device having a plurality of display faces with a small volume, and provide a personal digital assistant to realize a highly added value by using it. <P>SOLUTION: This is the light emitting device which has a plurality of light emitting elements as pixels and these light emitting elements emit light into mutually opposite directions, and pixel drive elements are installed on one side of the light emitting elements. The display on the both front and rear faces is possible, and images of respective display faces can be independently displayed, and the aperture rate for the sum of both sides together can be improved. Therefore, this electronic equipment using this display device will enable reading of different images on the both display faces while enabling further weight reduction and thinning. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light emitting device in which a pixel portion is formed of a light emitting element having a light emitting layer containing an electroluminescence (electroluminescence) substance between a pair of electrodes, and particularly to a light emitting device capable of displaying on two surfaces. . Moreover, it is related with the electronic device which has a display surface on two surfaces.

  In recent years, electronic devices, particularly portable information terminals (mobile computers, mobile phones, portable game machines, e-books, etc.) have been required to have high added value due to diversification of their purpose of use. A device provided with a sub display surface is provided (see Patent Document 1).

  In addition, as a light-emitting device using a self-luminous light-emitting element, for example, an organic EL display, an inorganic EL display, and the like have been actively studied. In particular, organic EL displays have features such as high image quality due to self-lighting, fast response speed suitable for moving image display, low voltage, low power consumption drive, thin structure by not using a backlight, and light weight. Therefore, it is attracting much attention as a next-generation display including portable information terminals.

  The light-emitting element in these light-emitting devices has a structure in which a layer containing a light-emitting substance is inserted between an electrode composed of a pair of a light-transmitting anode and cathode, and an electric field is applied to the anode and the cathode. Thus, electroluminescence is emitted from the layer containing the light-emitting substance. Here, all layers provided between the cathode and the anode are collectively referred to as a layer containing a light-emitting substance.

  These light-emitting devices employ a dot matrix method in which light-emitting elements are arranged in a matrix, and the driving method is roughly classified into a passive matrix driving method (simple matrix method) or an active matrix driving method. The

A passive matrix drive type display device has a cathode and an anode arranged in stripes, intersected in a matrix form, and a layer containing a luminescent material is formed between the electrodes at the intersecting position to constitute a pixel. To do. A luminance signal circuit or a control circuit with a built-in shift register is provided on the cathode or anode, respectively, and a signal voltage is applied to each electrode in time series by these circuits to selectively emit light at the pixel provided at the crossing position. . Since the passive matrix drive type display device has few manufacturing steps, the manufacturing cost can be reduced (see Patent Document 2).

In an active matrix drive display device, pixels each including an anode, a cathode, and a layer including a light emitting material provided therebetween are arranged in a matrix, and each pixel is provided with a pixel drive element (a transistor, a diode, or the like). . The pixel driving element is caused to function as a switch that is switched on / off by a scanning signal, and a data signal (display signal, video signal) is transmitted to the pixel electrode of the light emitting element through the pixel driving element in the on state. By writing the data signal to the light emitting element, the light emitting element emits light. An active matrix drive type display device is provided with a pixel drive element in each pixel, and thus has a high response speed and is suitable for displaying a moving image (see Patent Document 3). Note that an active matrix drive type display device is mainly used for an organic EL display.
JP 2002-101160 A JP 2001-155856 A JP 2001-013893 A

  In addition to the original display surface, a portable information terminal provided with a sub display surface cannot ignore the volume occupied by a substrate mounted with a control IC or the like for driving the modules in addition to the volume occupied by a plurality of modules. In particular, recently provided portable information terminals are remarkably light and thin, and are a trade-off for high added value.

  In view of the above problems, it is an object of the present invention to provide a light-emitting device that can be modularized with a small volume, and an electronic device that achieves high added value by using the light-emitting device, typically a portable information terminal. And

   The light-emitting device of the present invention has a plurality of light-emitting elements in a pixel, and these light-emitting elements emit light in directions opposite to each other, and one of the light-emitting elements is provided with a pixel driving element. It is characterized by. That is, among a plurality of light emitting elements provided in a pixel, one light emitting element is an active matrix driving type light emitting element, and the other light emitting element is a passive matrix driving type light emitting element or an area color light emitting element. It is characterized by being. With this structure, light can be emitted independently from the front and back of a single display device, and a light-emitting element that satisfies the functions required for each display unit can be provided. Typically, the main display can display with an active matrix light-emitting element, and the sub-display can display with a passive matrix light-emitting element or an area color light-emitting element. In the sub display, the entire display surface can be illuminated and used as a light. Furthermore, since one light-emitting element covers most of the non-light-emitting region of the other light-emitting element, the aperture ratio is significantly higher than that of a conventional pixel formed of a light-emitting element that can emit light on the front and back sides. . For this reason, contrast is improved and high-definition display is possible.

    Note that the light emitting device in this specification refers to a light emitting device or an image display device using a light emitting element. In addition, a module in which a connector such as an FPC (Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) is attached to the light emitting element, or a TAB tape or a module provided with a printed wiring board at the end of TCP Alternatively, a module in which an IC (Integrated Circuit) or a CPU is directly mounted on a light emitting element by a COG (Chip On Glass) method is included in the light emitting device.

  The light emitting device of the present invention based on the gist of the present invention described above can include the following configurations.

  In the present invention, pixels each having a first light emitting element and a second light emitting element are arranged in a matrix on a substrate, the first light emitting element emits light in a first direction, and the second light emitting element emits light. The element emits light in a second direction opposite to the first direction, and a semiconductor element is electrically connected to the first electrode of the first light emitting element. It is a light-emitting device.

  Note that the semiconductor element and the second light emitting element are formed between the first light emitting element and the substrate. Further, the first light emitting element and the semiconductor element may be formed between the second light emitting element and the substrate.

In addition, according to the present invention, a pixel including a first light-emitting element, a second light-emitting element, and a semiconductor element electrically connected to the first electrode of the first light-emitting element is formed in a matrix on a substrate. And an insulating film is formed between the first light-emitting element and the second light-emitting element, and the first light-emitting element includes a first electrode and a layer containing a first light-emitting substance. , And the second electrode has a stacked structure provided in order from the substrate side, and the second light-emitting element includes a third electrode, a layer containing a second light-emitting substance, and a fourth electrode. ,
A layered structure provided in order from the substrate side, wherein the second light emitting element and the semiconductor element are formed between the first light emitting element and the substrate; and the second electrode and the third electrode The light-emitting device is characterized in that the electrode has translucency.

  Note that the first electrode and the fourth electrode may have a light-transmitting property, and the insulating film may be colored. Further, the first electrode or the fourth electrode may have a light transmitting property, and the insulating film may be colored.

 In addition, according to the present invention, a pixel including a first light-emitting element, a second light-emitting element, and a semiconductor element electrically connected to the first electrode of the first light-emitting element is formed in a matrix on a substrate. And an insulating film is formed between the first light-emitting element and the second light-emitting element, and the first light-emitting element includes a first electrode and a layer containing a first light-emitting substance. , And the second electrode has a stacked structure provided in order from the substrate side, and the second light-emitting element includes a third electrode, a layer containing a second light-emitting substance, and a fourth electrode. The first light-emitting element and the semiconductor element are formed between the second light-emitting element and the substrate, and the first electrode and the fourth electrode are stacked. The light-emitting device is characterized in that the electrode has translucency.

  Note that the second electrode and the third electrode may have a light-transmitting property and the insulating film may be colored. Further, the second electrode or the third electrode may have a light-transmitting property, and the insulating film may be colored.

  The colored insulating film is an organic resin in which metal particles, carbon particles, or black pigments are dispersed.

  The first light emitting element is an active matrix driving type light emitting element, and the second light emitting element is a passive matrix driving type light emitting element. The first light emitting element may be an active matrix light emitting element, and the second light emitting element may be an area color light emitting element.

  The first light-emitting element or the second light-emitting element is a light-emitting element that emits light from an organic compound.

  The semiconductor element is a thin film transistor, a MOS transistor, an organic transistor, or a diode.

   According to the present invention, display on two front and back surfaces is possible, images on two surfaces can be displayed independently, and a light emitting device with a high aperture ratio combining the two surfaces can be manufactured.

  That is, in the present invention, in each pixel, one of the active matrix type or passive matrix type light emitting elements covers the other of the similar light emitting elements. For this reason, the sum of the light emitting regions in the pixel is the sum of the areas of the light emitting regions of the two light emitting elements, and the aperture ratio can be increased as compared with the pixel of the light emitting device using the conventional light emitting element.

  In addition, since the electronic device using the display device of the present invention can display the images on the front and back surfaces independently, it is possible to view the same image on both display surfaces at the same time without a sense of incongruity. It is also possible to browse different images on both screens. Further, high added value such as weight reduction and thinning of an electronic device having a plurality of display portions is realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, a thin film transistor (TFT) is used as the pixel driving element, but there is no particular limitation. For example, a semiconductor element such as a MOS transistor, an organic transistor, or a diode may be used similarly. The light-emitting element may be any light-emitting element having a light-emitting layer containing a light-emitting substance between a pair of electrodes. For example, an organic EL element using an organic compound as a light-emitting substance or an inorganic EL element using an inorganic compound as a light-emitting substance. An element etc. are mentioned. In the following embodiments, an organic EL element will be described as a light emitting element.

(Embodiment 1)
In this embodiment mode, a structure of a light-emitting device of the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of one pixel in a pixel portion of a light emitting device. In FIG. 1, 101 is a substrate, 102, 109 and 114 are insulating layers, 107 is a TFT, 111 and 121 are first electrodes of each pixel, 112 and 122 are layers containing a light emitting substance, and 113 and 123 are second layers. Electrode, 124 is a transparent protective layer, 125 is a sealing material, 130 is a counter substrate, 141 is a light emitting region of the first light emitting element, and 142 is a light emitting region of the second light emitting element.

  Note that the first light-emitting element is a passive matrix light-emitting element or a light-emitting element not provided with a pixel driving element such as an area color, and emits light toward the first substrate (that is, a bottom emission light-emitting element). .) In this embodiment, a passive matrix light-emitting element is used as the first light-emitting element. Here, the first electrode 111 is a row electrode (an electrode extending perpendicular to the paper surface), and the second electrode 113 is a column electrode (an electrode extending left and right with respect to the paper surface). But you can. On the other hand, the second light emitting element is provided with a pixel driving element (TFT 107), and emits light toward the second substrate (that is, a top emission light emitting element). Below, the detail of the structure of each light emitting element is demonstrated.

  The first light-emitting element includes a first electrode 111, a layer 112 containing a first light-emitting substance, and a second electrode 113. The second light-emitting element includes a first electrode 121, a layer 122 containing a second light-emitting substance, and a second electrode 123. The layer 112 containing a light-emitting substance is included in the first electrode. A TFT 107 which is an element for controlling a current flowing through the TFT is provided. Further, the first light emitting element and the second light emitting element are insulated by the third insulating layer 114.

  The first light-emitting element is provided over the substrate 101 with the first insulating layer 102 and the gate insulating film 110 interposed therebetween. Note that the structure of the insulating film between the first light-emitting element and the substrate is not limited to this, and another insulating film having a light-transmitting property may be provided. In the first light-emitting element, since the first electrode 111 side is in the light extraction direction, in the case where the first electrode is used as an anode, indium-tin oxide (ITO), indium-zinc oxide (IZO) ), Zinc oxide added with gallium (GZO), and a transparent conductive material such as ITO containing silicon oxide. In the case of a cathode, it is preferable to use a conductive material having translucency and a small work function. An alkaline metal such as Li or Cs and an alkaline earth metal such as Mg, Ca, or Sr are used. A stacked structure of an ultra thin film including the transparent conductive film (ITO, IZO, ZnO, GZO, ITO including silicon oxide, or the like) may be used. Alternatively, an electron injection layer in which an alkali metal or alkaline earth metal and an electron transport material are co-evaporated is formed, and a transparent conductive film (ITO, IZO, ZnO, GZO, ITO containing silicon oxide, etc.) is laminated thereon. Also good.

  The layer 112 containing the first light-emitting substance is formed by an evaporation method, a spin coating method, a coating method such as ink jetting, or the like. When the light emitting material is a low molecular weight material, the vapor deposition method is mainly used, and when the light emitting material is a medium molecule or polymer such as a dendrimer or oligomer, a coating method is mainly used. Here, the layer 112 containing a light-emitting substance is formed with a vapor deposition apparatus to obtain a uniform film thickness. Note that, in order to improve reliability, it is preferable to perform cleaning by UV irradiation or deaeration by vacuum heating (100 ° C. to 250 ° C.) immediately before the formation of the layer 112 containing a light-emitting substance. Note that the details of the structure of the layer 112 containing the first light-emitting substance are described in Embodiment 4.

The second electrode 113 has a polarity corresponding to that of the first electrode 111 and has a light shielding property. For example, when the first electrode 111 is an anode, the second electrode is a cathode, an alkali metal such as Li or Cs, an alkaline earth metal such as Mg, Ca, or Sr, and an alloy containing these (Mg: Ag , Al: Li, or the like), or a rare earth metal such as Yb or Er. Further, LiF, CsF, in the case of using an electron injecting layer such as CaF _2, Li ₂ O, may be used usual conductive thin film such as aluminum. In addition, when the first electrode 111 is a cathode, the second electrode is an anode, and the main components are titanium nitride and aluminum in addition to a single layer film such as TiN, ZrN, Ti, W, Ni, Pt, Cr, and Al. Or a three-layer structure of a titanium nitride film, a film containing aluminum as its main component, and a titanium nitride film can be used.

  As the third insulating layer 114 that insulates the first light emitting element from the second light emitting element, an interlayer insulating film 114 made of an organic material or an inorganic material is formed. As the interlayer insulating film 114, an inorganic material (silicon oxide, silicon nitride, silicon oxynitride, or the like), a photosensitive or non-photosensitive organic material (polyimide, acrylic, polyamide, polyimide amide, resist, benzocyclobutene, or siloxane) is used. Or a stack of these layers can be used. In this embodiment mode, a non-photosensitive organic resin is used as the third insulating layer. However, by using positive photosensitive acrylic as the organic resin material, an insulating film is formed as indicated by 109 in FIG. It is possible to provide a curved surface having a radius of curvature only at the upper end portion. As the insulating film, either a negative type that becomes insoluble in an etchant by photosensitive light or a positive type that becomes soluble in an etchant by light can be used.

  The second light-emitting element includes a first electrode 121, a layer 122 containing a second light-emitting substance, and a second electrode 123, and the second electrode 123 side is set as a light extraction direction. Therefore, when the TFT 107 is a p-channel TFT, the first electrode 121 serves as an anode, the second electrode 123 serves as a cathode, and the second electrode has a light-transmitting property and has a small work function. It is preferable to use a material, and an ultra-thin film containing an alkali metal such as Li or Cs and an alkaline earth metal such as Mg, Ca or Sr, and a transparent conductive film (ITO containing IZO, IZO, ZnO, GZO or silicon oxide) Etc.) may be used. Alternatively, an electron injection layer in which an alkali metal or alkaline earth metal and an electron transport material are co-evaporated is formed, and a transparent conductive film (ITO, IZO, ZnO, GZO, ITO containing silicon oxide, etc.) is laminated thereon. Also good. On the other hand, when the TFT 107 is an n-channel TFT, the first electrode 121 serves as a cathode and the second electrode 123 serves as an anode, indium-tin oxide (ITO), indium-zinc oxide (IZO), GZO, oxidation It is formed using a transparent conductive material such as ITO containing silicon. Note that the first electrode has a polarity corresponding to that of the second electrode 121 and is formed of a material exhibiting each polarity similarly to the second electrode of the first light-emitting element.

  The layer 122 containing the second light-emitting substance is formed using a method similar to that of the layer 112 containing the first light-emitting substance. Note that details of the structure of the layer 122 containing the second light-emitting substance are described in Embodiment 4.

  The TFT is provided over the substrate 101 with an insulating layer 102 interposed therebetween, and a semiconductor region, a semiconductor region formed by a channel formation region 103, a low concentration impurity region 104, and a high concentration impurity region (source region or drain region) 105 The gate insulating film 110, the gate electrode 106, and the drain electrode (or source electrode) 108 are provided between the gate electrode and the gate electrode.

  An interlayer insulating film 109 made of an organic material or an inorganic material is formed between the semiconductor region and the drain electrode (or source electrode) 108. For the interlayer insulating film 109, a material similar to that of the third insulating layer can be used. Note that in this embodiment mode, positive photosensitive acrylic is used as the material of the organic resin, so that only the upper end portion of the insulating film has a curved surface having a curvature radius.

  Although not shown here, one or more TFTs (n-channel TFTs or p-channel TFTs) are provided in one second light-emitting element. Although a TFT having one channel formation region 103 is shown here, the TFT is not particularly limited, and a TFT having a plurality of channels may be used. Although a TFT having a low concentration impurity region 104 is shown here, the present invention is not limited to this, and a TFT having a channel formation region 103 and a high concentration impurity region (source region and drain region) 105 may be used.

The semiconductor region 103 is formed of an amorphous semiconductor region or a crystalline semiconductor region. As a material for the semiconductor region, a single element or alloy of a semiconductor element (silicon, germanium, or the like), an organic semiconductor material, or the like can be used. An organic semiconductor material is an organic compound exhibiting semiconducting electrical properties with a specific resistance of about 10 ⁻² to 10 ¹⁶ Ωcm, and its structure is a π-electron conjugate whose skeleton is composed of conjugated double bonds. Polymeric materials of the system are desirable. Specifically, it is a soluble polymer material such as polythiophene, poly (3-alkylthiophene), and polythiophene derivatives. As the substrate and the counter substrate, alkali-free glass substrates such as aluminoborosilicate glass, barium borosilicate glass, and aluminosilicate glass, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PES (polyether sulfide), polypropylene, polypropylene A plastic substrate such as sulfide, polycarbonate, polyetherimide, polyphenylene sulfide, polyphenylene oxide, polysulfone, or polyphthalamide may be used.

  A transparent protective layer 124 is formed on the surface of the second electrode 123 of the second light emitting element. This is because a silicon nitride film, silicon oxide film, silicon oxynitride film (SiNO film (composition ratio N> O) or SiON film (composition ratio N <O)) obtained by sputtering or CVD, and carbon as a main component. A thin film (for example, a DLC film or a CN film) can be used and serves as a sealing film that protects the second electrode 123 made of a metal thin film and prevents moisture from entering.

  In addition, the substrate 101 provided with the first light-emitting element and the second light-emitting element and the counter substrate 130 are attached to each other with a sealant 125. The sealing material contains a gap material for securing the substrate interval, and is disposed so as to surround the pixel portion.

  In this embodiment mode, the first electrode 121 of the second light-emitting element covers the light-emitting region 141 of the first light-emitting element that is a passive matrix type. Therefore, the sum of the light emitting regions in the pixel is the sum of the areas of the light emitting regions 141 and 142 of the two light emitting elements. Since the aperture ratio of the conventional light emitting element is only the light emitting region of the first light emitting element or the second light emitting element, the aperture ratio can be increased according to the present invention.

(Embodiment 2)
In this embodiment, a structure different from that in Embodiment 1 in a light-emitting device having a plurality of light-emitting elements in one pixel will be described with reference to FIGS. In addition, about the site | part similar to FIG. 1, the detailed description is abbreviate | omitted using the same code | symbol.

  FIG. 2 is a cross-sectional view of one pixel in the pixel portion of the light emitting device. In FIG. 2, 101 is a first substrate, 102, 209, 214, 215 and 216 are insulating layers, 107 is a TFT, 211 and 221 are first electrodes of each light emitting element, and 212 and 222 are light emitting elements of each light emitting element. A layer containing a substance, 213 and 223 are second electrodes of each light emitting element, 224 is a transparent protective layer, 225 is a sealing material, 230 is a counter substrate, 241 is a light emitting region of the first light emitting element, 242 is a second electrode This is a light emitting region of the light emitting element.

  In this embodiment mode, the first light-emitting element is provided with a TFT 107 which is a pixel driving element, and emits light toward the first substrate (that is, a bottom emission light-emitting element). The light-emitting element is a passive matrix light-emitting element or a light-emitting element that is not provided with a pixel driving element such as an area color, and emits light toward the second substrate (that is, a top emission light-emitting element). In this embodiment, a passive matrix light-emitting element is used as the second light-emitting element. Here, the first electrode is a column electrode (an electrode extending left and right with respect to the paper surface) and the second electrode is a row electrode (an electrode extending perpendicular to the paper surface), but this may be reversed. . Below, the detail of the structure of each light emitting element is demonstrated.

    The first light-emitting element includes a first electrode 211, a layer 212 containing a first light-emitting substance, and a second electrode 213. The first electrode of the second light-emitting element includes a light-emitting substance. A TFT 107 which is an element for controlling a current flowing in the layer 212 including the element is provided. The layer 212 containing the first light-emitting substance is formed over the first electrode 211 and the third insulating layer 214. Here, the third insulating layer 214 is an insulating layer covering the end portion of the first electrode 211, the second insulating layer 209, and the drain electrode (or source electrode) 108, and includes a bank, a partition wall, a barrier, It is called a bank.

  The second light-emitting element includes a first electrode 221, a layer 222 containing a second light-emitting substance, and a second electrode 223. Further, the first light-emitting element and the second light-emitting element are insulated by the fourth insulating layer 215.

  First, the first light emitting element will be described. The first light-emitting element is provided over the substrate 101 via a plurality of insulating layers (a first insulating layer 102, a gate insulating film 110, and a second insulating layer 209). In the first light-emitting element, the first electrode 211 side is set as a light extraction direction. Therefore, when the TFT 107 is a p-channel TFT, the first electrode 211 serves as an anode, and the first light emission in Embodiment 1 is performed. It is formed of the same material as the anode that is the first electrode of the element. On the other hand, when the TFT 107 is an n-channel TFT, the first electrode 211 serves as a cathode and is formed using the same material as the cathode that is the first electrode of the first light-emitting element of Embodiment 1. On the other hand, the layer 212 containing the first light-emitting substance and the second electrode 213 are formed using the same materials (112 and 113 respectively) as those of the first light-emitting element of Embodiment 1.

  The pixel driving element TFT 107 connected to the first electrode 211 of the first light emitting element is formed using the same element as that in the first embodiment. Note that in this embodiment mode, the first electrode 211 is formed after the drain electrode (or source electrode) 108 of the TFT 107 is formed; however, the present invention is not limited to this structure. For example, the drain electrode (or source electrode) 108 of the TFT 107 may be formed after the first electrode 211 is formed, and the drain electrode (or source electrode) 108 of the TFT 107 and the first electrode 211 are made of the same material. , May be formed simultaneously.

  An interlayer insulating film 209 made of an organic material or an inorganic material is formed between the semiconductor region and the drain electrode (or source electrode) 108. As the interlayer insulator 209, a material similar to that of the third insulating layer 114 in Embodiment 1 can be used. Note that in this embodiment mode, non-photosensitive acrylic is used as the material of the organic resin, so that the upper end portion of the insulator does not have a curved surface having a radius of curvature as indicated by 109 in FIG.

  The layer 212 containing the first light-emitting substance is formed using a method similar to that of the layer 112 containing the first light-emitting substance of the first light-emitting element described in Embodiment 1. Note that details of the structure of the layer 222 containing the second light-emitting substance are described in Embodiment 4.

  The second electrode has a polarity corresponding to that of the first electrode 211 and is formed using the same material as that of the second electrode of the first light-emitting element described in Embodiment 1.

  As a fourth insulating layer 215 that insulates the first light-emitting element and the second light-emitting element, an interlayer insulating film 215 made of an organic material or an inorganic material is formed. The interlayer insulating film 215 is formed using the same material as that of the third interlayer insulating layer 114 of Embodiment 1.

  The second light-emitting element includes a first electrode 221, a layer 222 containing a second light-emitting substance, and a second electrode, and the second electrode 223 side is set as a light extraction direction. Therefore, the second electrode 223 is formed using the same material as the second electrode 123 of the second light-emitting element of Embodiment 1. In addition, the first electrode 221 and the layer 222 containing a second light-emitting substance are also formed in the same manner as the first electrode 121 and the layer 122 containing a second light-emitting substance in Embodiment 1. The first electrode 223 is also formed using a material similar to that of the first electrode 121 of the second light-emitting element in Embodiment 1.

  In this embodiment mode, the first electrode 221 of the second light-emitting element covers the light-emitting region 241 of the first light-emitting element that is an active matrix type. Therefore, the sum of the light emitting regions in the pixel is the sum of the areas of the light emitting regions 241 and 242 of the two light emitting elements, and the aperture ratio can be increased as compared with the pixel of the light emitting device using the conventional light emitting element.

(Embodiment 3)
In this embodiment mode, each of the first light-emitting element and the second light-emitting element in Embodiment 1 or Embodiment 2 is formed using a light-transmitting electrode, and the first light-emitting element and the first light-emitting element The display device is characterized in that the interlayer insulating layer that insulates the two light emitting elements is formed of a colored material, preferably a material that does not substantially transmit visible light. The structure of the light-emitting device of this embodiment will be described using the example described in Embodiment 1 as an example with reference to FIG.

  The first electrode and the second electrode of the first light-emitting element and the second light-emitting element are formed using a light-transmitting conductive film. When the first electrode is an anode, the first electrode is formed using a transparent conductive material such as ITO containing indium-tin oxide (ITO), indium-zinc oxide (IZO), GZO, or silicon oxide. In this case, the second electrode serves as a cathode, and it is preferable to use a conductive material having translucency and a low work function. Alkali metals such as Li and Cs, and alkaline earth such as Mg, Ca, and Sr are used. A stacked structure of an ultrathin film containing a similar metal and a transparent conductive film (ITO, IZO, ZnO, or the like) may be used. Alternatively, an electron injection layer in which an alkali metal or an alkaline earth metal and an electron transport material are co-evaporated may be formed, and a transparent conductive film (ITO, IZO, ZnO, or the like) may be stacked thereon. In the case where the first electrode is a cathode and the second electrode is an anode, an electrode material that similarly exhibits each polarity and has a light transmitting property may be used as appropriate.

  In this case, the light emitted from one light-emitting element is not emitted toward the other light-emitting element, and the display content on each display surface is doubled. For this reason, the layered insulating layer (114 in FIG. 1 and 215 in FIG. 2) that insulates each light emitting element is colored, preferably a material that does not reflect and does not substantially transmit visible light Form with. Examples of the material for the interlayer insulating layer include a metal film (such as chromium), carbon particles, or an insulating film (preferably an organic resin film) containing a black pigment.

  With the structure of this embodiment mode, when a reflective material is used for a light-shielding electrode (for example, the second electrode of the first light-emitting element, the first electrode of the second light-emitting element, or the like). The reflection of the external scenery that occurs (the state where the scenery is reflected by each reflective electrode and the external scenery appears on the display surface (the surface that faces the observer)) can be prevented. For this reason, it is not necessary to use an expensive circularly polarizing film, and since there is no loss of emitted light due to the circularly polarizing film, it is possible to obtain a light emitting device that is inexpensive and has good image quality.

  Note that the second electrode of the first light-emitting element is a light-shielding electrode, the first electrode of the second light-emitting element is formed of a light-transmitting electrode, and the interlayer insulating layer is colored Alternatively, it may be formed of a material that does not reflect and does not substantially transmit visible light. In this case, reflection occurs when the second electrode of the first light-emitting element is formed using a reflective conductive film. However, if the display surface formed by the first light-emitting element is used as a sub display surface. , Relatively less affected by reflections.

(Embodiment 4)
In this embodiment mode, a structure of a layer containing a light-emitting substance of the light-emitting element that can be applied in Embodiment Modes 1 to 3 (112 and 122 in Embodiment Mode 1 and 212 and 222 in Embodiment Mode 2) Will be described with reference to FIG.

  The light-emitting element includes a pair of an anode and a cathode, and a layer containing a light-emitting substance sandwiched between the anode and the cathode. Hereinafter, the electrode provided on the substrate side is referred to as a first electrode, and the electrode provided on the opposite side of the substrate is referred to as a second electrode.

  The layer containing a light-emitting substance includes at least a light-emitting layer, and includes any one or a plurality of layers having different functions for carriers, such as a hole injection layer, a hole transport layer, a blocking layer, an electron transport layer, and an electron injection layer. It is formed by combining and laminating.

  FIG. 3 illustrates an example of a cross-sectional structure of the light-emitting element.

  In FIG. 3A, a layer 1303 containing a light-emitting substance is formed over a first electrode (anode) 1301 with a hole injection layer 1304, a hole transport layer 1305, a light-emitting layer 1306, an electron transport layer 1307, and an electron injection. A layer 1308 is stacked, and a second electrode (cathode) 1302 is provided in contact with the electron injection layer 1308. This structure is referred to herein as a progressive stacking element.

  In FIG. 3B, the layer 1313 containing a light-emitting substance is formed over the first electrode (cathode) 1311 with an electron injection layer 1318, an electron transport layer 1317, a light-emitting layer 1316, a hole transport layer 1315, and a positive electrode. A hole injection layer 1314 is stacked, and a second electrode (anode) 1312 is provided in contact with the hole injection layer 1314. This structure is referred to herein as a reverse stacked element.

  In this embodiment mode, the first light-emitting element and the second light-emitting element can have a structure illustrated in FIG. 3A or 3B. Either the first light-emitting element or the second light-emitting element may form a forward-stacked element or a reverse-stacked element, and if one is a forward-stacked element, the other forms a reverse-stacked element. May be. The light-emitting elements of Embodiments 1 and 2 preferably have the former stacked structure.

  The present embodiment is not limited to this, and various light-emitting element structures such as anode / hole injection layer / light-emitting layer / electron transport layer / cathode, anode / hole injection layer / hole transport layer / Light emitting layer / electron transport layer / electron injection layer / cathode, anode / hole injection layer / hole transport layer / light emission layer / hole blocking layer / electron transport layer / cathode, anode / hole injection layer / hole transport A structure such as a layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode may be used. Note that examples of the arrangement of the light emitting regions, that is, the arrangement of the pixel electrodes include a stripe arrangement, a delta arrangement, and a mosaic arrangement.

  As a material for forming the layers 1303 and 1313 containing a light-emitting substance, a known organic compound having a low molecular weight, a high molecular weight, or a medium molecular weight typified by an oligomer or a dendrimer can be used. Alternatively, a light-emitting material (fluorescent material or singlet compound) that emits light (fluorescence) by singlet excitation or a light-emitting material (phosphorescent material or triplet compound) that emits light (phosphorescence) by triplet excitation can be used.

  Specific examples of materials for forming the layers 1303 and 1313 containing a light-emitting substance are shown below.

As a hole injection material for forming the hole injection layers 1304 and 1314, porphyrin compounds are effective as long as they are organic compounds, and phthalocyanine (hereinafter referred to as H ₂ -Pc), copper phthalocyanine (hereinafter referred to as Cu--). And the like can be used. There are also materials obtained by chemically doping conductive polymer compounds, such as polyethylenedioxythiophene (hereinafter referred to as PEDOT) doped with polystyrene sulfonic acid (hereinafter referred to as PSS), polyaniline, polyvinylcarbazole (hereinafter referred to as PVK). For example). In addition, an inorganic semiconductor thin film such as vanadium pentoxide or molybdenum oxide or an ultrathin film of an inorganic insulator such as aluminum oxide is also effective.

As the hole transporting material for forming the hole transporting layers 1305 and 1315, an aromatic amine-based compound (that is, a compound having a benzene ring-nitrogen bond) is preferable. As a widely used material, for example, N, N′-bis (3-methylphenyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine (abbreviation: TPD), 4,4'-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (abbreviation: α-NPD) which is a derivative thereof. 4
, 4 ′, 4 ″ -tris (N, N-diphenyl-amino) -triphenylamine (abbreviation: TDATA) and 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N And starburst aromatic amine compounds such as -phenyl-amino] -triphenylamine (abbreviation: MTDATA).

Specific examples of a light emitting material for forming the light emitting layers 1306 and 1316 include tris (8-quinolinolato) aluminum (hereinafter referred to as Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (hereinafter referred to as Almq _3). ), Bis (10-hydroxybenzo [h] -quinolinato) beryllium (hereinafter referred to as BeBq ₂ ), bis (2-methyl-8-quinolinolato)-(4-hydroxy-biphenylyl) -aluminum (hereinafter referred to as BAlq). ), Bis [2- (2-hydroxyphenyl) -benzoxazolate] zinc (hereinafter referred to as Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) -benzothiazolate] zinc (hereinafter referred to as In addition to metal complexes such as Zn (BTZ) ₂ , various fluorescent dyes are effective. A triplet light emitting material is also possible, and is mainly a complex having platinum or iridium as a central metal. As the triplet light emitting material, tris (2-phenylpyridine) iridium (hereinafter referred to as Ir (ppy) ₃ ), 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin -Platinum (hereinafter referred to as PtOEP) is known.

As an electron transport material for forming the electron transport layers 1307 and 1317, tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10 -Hydroxybenzo [h] -quinolinato) beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato)-(4-hydroxy-biphenylyl) -aluminum (abbreviation: BAlq), bis [2- (2- Metal complexes such as hydroxyphenyl) -benzoxazolate] zinc (abbreviation: Zn (BOX) ₂ ) and bis [2- (2-hydroxyphenyl) -benzothiazolate] zinc (abbreviation: Zn (BTZ) ₂ ). . In addition to metal complexes, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- Oxadiazole derivatives such as (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4 -Phenyl-5- (4-biphenylyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) ) -1,2,4-triazole (abbreviation: p-EtTAZ) derivative, 2,2 ′, 2 ″-(1,3,5-benzenetriyl) tris [1-phenyl-1H-benzimidazole ] An imidazole derivative such as (abbreviation: TPBI), a phenanthroline derivative such as bathophenanthroline (abbreviation: BPhen), and bathocuproin (abbreviation: BCP) can be used.

As the electron injecting material that can be used for the electron injecting layers 1308 and 1318, the above-described electron transporting materials can be used. In addition, an ultra-thin film of an insulator such as an alkali metal halide such as LiF or CsF, an alkaline earth halide such as CaF ₂ , or an alkali metal oxide such as Li ₂ O is often used. In addition, alkali metal complexes such as lithium acetylacetonate (abbreviation: Li (acac) and 8-quinolinolato-lithium (abbreviation: Liq) are also effective.

  For the layer containing a light-emitting substance of the light-emitting element described in any of Embodiments 1 to 3, the structure and materials described above can be selected as appropriate.

  In the case where the light-emitting device of this embodiment mode is a full-color display, a material layer that emits red, green, and blue light can be deposited as the layers 1303 and 1313 containing a light-emitting substance using an evaporation mask. Further, instead of this method, a film can be selectively formed as appropriate, such as a spin coating method or an ink jet method.

  Further, a layer containing a light emitting substance may emit white light, and a full color display may be performed by separately providing a color filter. Alternatively, a layer containing a light emitting substance may emit blue light, and a full color display may be performed by separately providing a color conversion layer or the like.

(Embodiment 5)
Next, a driving method of the light-emitting device of the present invention described in Embodiments 1 to 4 will be described below.

  In this embodiment mode, the source region and the drain region of a TFT are difficult to distinguish depending on the structure and operating conditions, and thus one is described as a first electrode and the other as a second electrode. The first light-emitting element is a bottom-emission light-emitting element, the second light-emitting element is a top-emission light-emitting element, and regions where emitted light is obtained are a first region and a second region, respectively. One unit is included in the unit.

  An example of this embodiment is shown in FIG. Here, an example in which light emission and non-light emission control of the second light-emitting element 3007 is performed by the switching TFT 3004 and the driving TFT 3005, respectively.

  A region surrounded by a dotted frame 3000 is a pixel of a repeating unit of the light-emitting device. The second light-emitting element 3007, the source signal line 3001 of the second light-emitting element, the gate signal line 3002, and the power supply line (constant voltage or constant). A wiring for supplying current) 3003, a switching TFT 3004 and a driving TFT 3005 for the second light emitting element, a first light emitting element 3008, a row electrode signal line 3011 and a column electrode signal line 3012 for the first light emitting element.

  The gate electrode of the switching TFT 3004 of the second light emitting element is electrically connected to the gate signal line 3002, the first electrode is electrically connected to the source signal line 3001, and the second electrode is for driving. It is electrically connected to the gate electrode of the TFT 3005. The first electrode of the driving TFT 3005 is electrically connected to a power supply line (wiring for supplying a constant voltage or a constant current) 3003, and the second electrode is electrically connected to the first electrode of the second light emitting element 3007. Connected.

  On the other hand, the row electrode signal line 3011 is a first electrode of the first light emitting element, and the column electrode signal line 3012 is a second electrode of the first light emitting element.

  The video signal input to the source signal line 3001 is input to the gate electrode of the driving TFT 3005 at a timing when the switching TFT 3004 is turned on, and current is supplied to the second light emitting element 3007 according to the video signal to emit light. To do. When the row electrode signal line 3011 and the column electrode signal line 3012 are turned on, the first light emitting element emits light. As described above, outgoing light is obtained from the front and back of the substrate in each of the first region and the second region.

  Note that when the first light-emitting element is an area-color light-emitting element, the power supply line (wiring for supplying a constant voltage or a constant current) 3003 and the column electrode are shared, and the first light-emitting element is turned on and off in a column. You may control by an electrode. In addition, although the example in which the driving TFT for controlling light emission and non-light emission of the second light emitting element is provided in the pixel is shown, it is not limited to this, and the outside of the pixel portion (peripheral portion), an external IC chip, etc. It may be used.

    With the above driving method, different images can be simultaneously displayed on the first region and the second region, that is, on the front and back of the light emitting device. Therefore, it is possible to form a light-emitting device having a light-emitting element that meets the display content required for each display surface.

  In this example, a manufacturing process of the light-emitting element having the structure of Embodiment Mode 1 will be described with reference to FIGS.

  FIG. 4 shows a step of forming a first electrode of the first light-emitting element and a part of the TFT of the second light-emitting element. FIG. 4A is a top view and FIG. It is sectional drawing of (A)-(A ') of FIG. 4 (A).

As shown in FIG. 4A, a base insulating film 402 is formed over a glass substrate (first substrate 401). In this embodiment, the base insulating film has a two-layer structure, and the first silicon oxynitride film formed using SiH ₄ , NH ₃ , and N ₂ O as a reaction gas is 50 to 100 nm, SiH ₄ , and N _2. A second silicon oxynitride film formed using O as a reaction gas is stacked to a thickness of 100 to 150 nm.

  Next, an amorphous silicon film is formed over the base insulating film by a known method such as a plasma CVD method, a low pressure CVD method, or a sputtering method, and heat treatment is performed for crystallization. In this case, in crystallization, silicide is formed in a portion of the semiconductor film in contact with a metal element that promotes crystallization of the semiconductor, and crystallization proceeds using the silicide as a nucleus. Here, after heat treatment for dehydrogenation (450 ° C., 1 hour), heat treatment for crystallization (550 to 650 ° C. for 4 to 24 hours) is performed.

  Thereafter, gettering of the metal element is performed from the crystalline silicon film by a known method, and the metal element in the crystalline silicon film is removed or the concentration is reduced. Next, it is preferable to irradiate the crystalline silicon film with a laser beam in order to increase the crystallization rate (the ratio of the crystal component in the total volume of the film) and repair defects remaining in the crystal grains.

  Next, a TFT is formed by a known method using a crystalline silicon film. The crystalline silicon film is etched into a desired shape to form semiconductor regions 403a, 403b, and 403c. 403a is a semiconductor region of the switching TFT of the second light emitting element, 403b is a semiconductor region of the driving TFT of the second light emitting element, and 403c is a capacitor element formed between the source region and the gate electrode of the driving TFT. Become part. Next, after cleaning the surface of the silicon film with an etchant containing hydrofluoric acid, an insulating film containing silicon as a main component and serving as the gate insulating film 404 is formed.

  Next, a known conductive film, here a laminated film of tantalum nitride and tungsten, is formed and etched into a desired shape to form gate electrodes (gate signal lines) 405a and 405b.

  Next, an impurity element imparting n-type conductivity (P, As, etc.) and an impurity element imparting P-type conductivity (B, etc.), here phosphorus and boron, are added as appropriate, so that an n-channel TFT and a p-channel transistor are added. A source region and a drain region of the TFT are formed.

  Next, after part of the switching TFT 407a is etched to expose part of the source region of the semiconductor region 403a, a conductive film is formed and etched into a desired shape to be connected to the source region of the switching TFT 407a. An electrode 406 is formed.

Next, after a second insulating film (not shown) is formed over the substrate, heat treatment or intense light irradiation is performed to activate the added impurity element. This step can recover plasma damage to the gate insulating film and plasma damage to the interface between the gate insulating film and the semiconductor film simultaneously with activation.

  Next, an acrylic resin is applied on the second insulating film. In this embodiment, a positive photosensitive acrylic resin is used. Thereafter, the positive photosensitive acrylic resin is exposed by a photolithography process, and the organic resin is developed to form a first interlayer insulating film 408. Since the first interlayer insulating film has the first opening having a curvature, there is an effect that the coverage (coverage) of an electrode to be formed later is increased. In addition, since a photosensitive acrylic resin is used, the first opening can be formed by development and exposure without forming a resist mask, and the resist mask needs to be ashed or removed with a stripping solution. There is no process reduction.

  Next, a known transparent conductive film, here ITO, is formed and etched into a desired shape to form row electrodes 409.

  FIG. 5 illustrates a step of forming a layer containing a light-emitting substance of the first light-emitting element, a second electrode, and a TFT of the second light-emitting element. FIG. 5A is a top view thereof, FIG. FIG. 5B is a cross-sectional view taken along line (A)-(A ′) of FIG.

A layer 419 including a first light-emitting substance is formed over the first pixel electrode (row electrode) 409 of the first light-emitting element. The green light emitting element has a stacked structure of 20 nm CuPc, 30 m α-NPD, and 50 nm Alq ₃ . Next, 1-10 nm of Ag—Mg and 50-200 nm of ITO are stacked and etched into a desired shape to form a second pixel electrode (column electrode) 412 of the first light emitting element. . In FIG. 5A, the light-emitting region of the first light-emitting element is 420. Note that as the layer containing the first light-emitting substance, the material described in Embodiment 4 is used as appropriate to form a red light-emitting element or a blue light-emitting element as appropriate in addition to the green light-emitting element.

  Next, after etching the first interlayer insulating film 408, the second insulating film, and the gate insulating film 404 to expose the drain region of the switching TFT, the source region and the drain region of the driving TFT, Here, a titanium film (film thickness 100 nm) / aluminum-silicon alloy film (film thickness 350 nm) / titanium film (film thickness 100 nm) (Ti / Al-Si / Ti) is formed, etched into a desired shape, and then source An electrode 411 and drain electrodes 410a and 410b are formed. In this embodiment, the source electrode 411 of the driving TFT 407b is a part of the source electrode signal line. The light emitting region of the first light emitting element is 420.

  Note that the source electrode and the drain electrode can also be formed by landing a metal solution on the first opening region using an inkjet method. In this case, the steps for forming and removing the resist mask can be reduced.

  6A and 6B illustrate a step of forming the second light-emitting element. FIG. 6A is a top view thereof, and FIG. 6B is a cross-sectional view of (A)-(A ′) in FIG. FIG.

  Next, an insulating film is formed over the entire surface of the substrate to form a second interlayer insulating film 413. In this embodiment, a non-photosensitive acrylic resin is used as the second interlayer insulating film. Next, after etching a part of the second interlayer insulating film to expose a part of the drain electrode of the driving TFT 407b, a known conductive film, here an Ag film, is deposited, and then ITO is laminated. These are etched into a desired shape to form the first pixel electrode 414 of the second light emitting element.

Next, a layer 415 containing a second light-emitting substance is formed in the pixel portion, and a second pixel electrode 416 is formed thereon. The layer containing the second light-emitting substance has a stacked structure of 50 nm Alq ₃ , 30 m α-NPD, and 20 nm CuPc. In addition to the green light-emitting element, a red light-emitting element or a blue light-emitting element is formed as appropriate, using the material described in Embodiment 4 as appropriate, similarly to the layer containing the first light-emitting substance.

  The first pixel electrode 414, the layer 415 containing the second light-emitting substance, and the second pixel electrode 416 constitute a second light-emitting element. In addition, the light emitting region 418 of the second light emitting element covers the light emitting region 420 of the first light emitting element.

  Next, a transparent protective film 417 formed of a silicon nitride oxide film, a silicon oxynitride film (SiON (O> N), SiNO (N> O)) is formed on the entire surface of the substrate, and water and oxygen are transmitted. Suppress.

  As shown in FIG. 7, a pixel driving circuit is provided on a substrate provided with a pixel portion, and an n-channel TFT and a p-channel TFT are formed as a CMOS circuit so that the driving circuit and the pixel portion are the same. A display device formed over a substrate can be obtained.

  FIG. 7 is a top view showing the light emitting device. In FIG. 7, 1101 indicated by a dotted line is a pixel portion, 1102 is a source signal line driving circuit of the first light emitting element, and 1104 is a gate signal line driving circuit of the first light emitting element. Reference numeral 1103 denotes a column electrode driving circuit for the second light emitting element, and reference numeral 1105 denotes a row electrode driving circuit for the second light emitting element. Reference numeral 1107 denotes a first substrate, 1108 denotes a counter substrate, 1106 denotes a sealing material containing a gap material for maintaining a gap between a pair of substrates, and the inside surrounded by the sealing material 1106 is filled with a sealing material Has been. In this embodiment, a highly viscous epoxy resin containing a filler is used as the sealing material.

  Further, an external input terminal 1110 such as an FPC (Flexible printed circuit), a TAB (Tape Automated Bonding) tape, or a TCP (Tape Carrier Package) is provided, a source signal line driving circuit 1102, a column electrode driving circuit 1103, a gate signal. Signals such as video signals and clock signals input to the line driver circuit 1104 and the row electrode driver circuit 1105 are transmitted through the connection wiring 1109. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC.

  Note that in this example, the manufacturing process of the light-emitting device described in Embodiment Mode 1 was described; however, the manufacturing process of the light-emitting device described in Embodiment Mode 2 can be applied.

  In this embodiment, a structure example of a light-emitting device in which at least a pixel portion, a driver circuit for driving a pixel, and an image processing circuit are formed over a substrate having an insulating surface and an operation method for reducing power consumption will be described.

  FIG. 11 illustrates an example of a system having a display portion formed over a glass substrate. On the glass substrate, a pixel portion 801, a source line driver circuit 802, a gate line driver circuit 803, and three different functions are provided. Two image processing circuits 804 to 806, a memory 807, an interface circuit 808, and a power supply timing control circuit 809 are provided.

  In the block diagram illustrated in FIG. 11, a pixel portion 801 is a portion that displays an image, and a source line driver circuit 802 and a gate line driver circuit 803 are driver circuits that drive pixels. Image data is input to the source line driver circuit 802. The interface circuit 808 receives image data or image base data from the outside, converts the image data into an appropriate internal signal, and outputs the internal signal to the source line driver circuit 802, the image processing circuits 804 to 806, or the memory 807. .

  As a function of the light emitting device, various image processing using the three image processing circuits 804 to 806 and the memory 807 can be performed. For example, by using one or more of these image processing circuits, image conversion such as image distortion correction, resizing, mosaic processing, scrolling, and inversion, multi-window processing, image generation using the memory 807, and these Complex processing can be considered.

  Corresponding to this, various operation modes can be considered, and in the light emitting device of this configuration, it is effective to apply a nonvolatile latch circuit to the registers and latch circuits included in the image processing circuits 804 to 806. . That is, a configuration in which the logical states of the image processing circuits 804 to 806 can be restored by a nonvolatile latch circuit is effective. By doing so, it is possible to cut off the power supply while maintaining the operation state of the image processing circuits 804 to 806, and it is possible to cut off the power supply of the image processing circuits that are not used. As a result, power consumption can be reduced.

  In addition, even during standby, the power supply can be stopped while maintaining the system status, so it is possible to simultaneously achieve high-speed transition between standby and operation and reduction of power consumption during standby. It becomes.

  The operation mode switching control is performed by a power supply timing control circuit 809. Specifically, in accordance with the operation mode, the storage procedure and the restoration procedure may be performed on the image processing circuit that is not used before and after the mode switching.

  In this embodiment, the case where the entire image processing circuits 804 to 806 can be restored has been described. However, the present invention is not necessarily limited to this. The image processing circuits 804 to 806 may be configured to be able to restore the logic states of some of the circuits (for example, the circuit C). In that case, power can be supplied to the circuit C only when the circuit C is used, and power consumption can be reduced.

  In addition, a nonvolatile latch circuit can be applied to the interface circuit, the source line driver circuit, or the gate line driver circuit. As a result, when each logic circuit does not operate, power consumption can be reduced by shutting off the power supply of the logic circuit.

  In addition, this embodiment can be freely combined with any structure of Embodiment Modes 1 to 5 and Embodiment 1.

 Electric appliances having the light-emitting devices formed in Embodiments 1 to 5 and Examples 1 to 2 will be described. Typically, a video camera, a digital camera, a notebook personal computer, a portable information terminal (such as a mobile computer, a mobile phone, a portable game machine, or an electronic book), and an image reproducing device (specifically, a digital device) including a recording medium A device having a display capable of reproducing a recording medium such as a video disc (DVD) and displaying the image), a television receiver, an electric bulletin board, a register, and the like. In this embodiment, an example in which the light-emitting device of the present invention is applied to a mobile phone is shown as a typical example of these.

  9A and 9B are schematic views of a mobile phone according to the present invention, in which FIG. 9A is a perspective view in an opened state, and FIG. 9B is a perspective view in a closed state of the same, It is the perspective view seen from the 1st housing | casing side provided with 2 display surfaces.

  In the mobile phone, two housings (a first housing 8000a and a second housing 8000b) are connected by a hinge 8101, and can be rotated around the hinge 8101.

  The first housing 8000a is provided with a first display surface 8001a, a second display surface 8001b, operation buttons 8002b, speakers 8003a and 8003b, an antenna 8004, a camera lens 8005, and the like.

  On the other hand, the second housing 8000b includes operation buttons 8002a, a microphone 8102, and the like.

  When the cellular phone is open, the first display surface 8001a is used as a main display surface. The screen operation is performed using the operation button 8002a. When the cellular phone is closed, the second display surface 8001b is used as a main display surface. In this case, the display information is operated with the operation button 8002b.

  FIG. 9C is a cross-sectional view of the mobile phone in FIG. 9A viewed from the side. A display controller 8008 connected to the display unit is provided inside the first casing 8000a, and controls display contents. In addition, a battery 8010 and a main body driving module 8009 are provided inside the second housing 8000b, and the display unit, the display controller 8008, the main body driving module 8009, and the like are driven using the power generated in the battery 8010. To do.

  FIG. 9D is an enlarged view of a region A in FIG. The first display surface 8001a and the second display surface 8001b display images emitted from the display portion 8013 (including light-emitting elements formed between the substrate 8011 and the counter substrate 8012) on each display surface. is doing.

  By using the light-emitting devices described in Embodiments 1 to 5 and Examples 1 and 2 for the display portion 8013 of this embodiment, two light-emitting devices can display two display surfaces (a first display surface 8001a and a second display surface). Display surface 8001b), and information suitable for the contents of each display unit can be displayed. For example, a light-emitting element that can be displayed on the first display portion is a light-emitting element of an active matrix driving method, and a light-emitting element that can be displayed on the second display portion is a light-emitting element of a passive matrix driving method or light emission for area color. By using the element, high-definition images and moving images can be displayed on the first display unit, and simple information such as a clock and an incoming mail status can be displayed on the second display unit.

  Conventionally, in order to display the first display surface and the second display surface, two display devices are necessary. In this embodiment, one display device can display on different display surfaces. The volume and weight of the mobile phone can be reduced, and the size of the device can be reduced.

  Conventionally, the display unit having the second display surface can be incorporated only with a small display area because of space, but according to the present invention, the display unit having the same display size as that of the first display surface 8001a can be provided. Since the second display surface 8001b can be provided, high added value can be realized.

    In this example, a register is used as an example of an electronic device to which Embodiment Modes 1 to 5 and Examples 1 and 2 are applied.

  FIG. 10 is a side view of a register according to the present invention, in which a first housing 9000a and a second housing 9000b are connected by a hinge 9001, and the second housing 9000b can rotate.

  The first housing 9000 a is provided with a portion for taking out the operation button 9003 and the receipt 9004. On the other hand, the second casing 9000b is provided with a first display portion 9002a and a second display portion 9002b on both sides. The first display portion 9002a faces the salesperson, and the second display portion 9002b faces the purchaser.

  When the light-emitting device of the present invention is used for the first display portion 9002a and the second display portion 9002b, two display surfaces can be provided with one display device, so that the thickness of the display portion can be suppressed. Thus, the weight of the display portion is reduced and the thickness is reduced. Further, the calculated value of the product is displayed on the first display unit, and the advertisement or TV image is displayed on the second display unit, so that the salesperson 9005 finishes calculating the product. The purchaser 9006 can watch advertisements, television images, and the like, and can receive information on merchandise without taking time to spare.

FIG. 6 illustrates a cross section of a light-emitting device of the present invention. FIG. 6 illustrates a cross section of a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a process for manufacturing a light-emitting device of the present invention. 4A and 4B illustrate a process for manufacturing a light-emitting device of the present invention. 4A and 4B illustrate a process for manufacturing a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a driving method of a light-emitting device of the present invention. 8A and 8B each illustrate an example of an electronic device of the invention. 8A and 8B each illustrate an example of an electronic device of the invention. The figure which shows the system block diagram of a light-emitting device.

Claims (15)

Pixels having a first light emitting element and a second light emitting element are arranged in a matrix on the substrate,
The first light emitting element emits light in a first direction;
The second light emitting element emits light in a second direction opposite to the first direction;
A light-emitting device, wherein a semiconductor element is electrically connected to the first electrode of the first light-emitting element.   2. The light emitting device according to claim 1, wherein the semiconductor element and the second light emitting element are formed between the first light emitting element and the substrate.   The light-emitting device according to claim 1, wherein the first light-emitting element and the semiconductor element are formed between the second light-emitting element and the substrate. Pixels each including a first light-emitting element, a second light-emitting element, and a semiconductor element electrically connected to the first electrode of the first light-emitting element are arranged in a matrix over a substrate, and An insulating film is formed between the light-emitting element and the second light-emitting element. The first light-emitting element includes a first electrode, a layer containing a first light-emitting substance, and a second electrode. , Having a laminated structure provided in order from the substrate side,
The second light-emitting element has a stacked structure in which a third electrode, a layer containing a second light-emitting substance, and a fourth electrode are sequentially provided from the substrate side. The light-emitting device, wherein the second light-emitting element and the semiconductor element are formed between the substrate and the substrate, and the second electrode and the third electrode have translucency.   5. The light-emitting device according to claim 4, wherein the first electrode and the fourth electrode have a light-transmitting property and the insulating film is colored.   5. The light-emitting device according to claim 4, wherein the first electrode or the fourth electrode has a light-transmitting property and the insulating film is colored.  Pixels each including a first light-emitting element, a second light-emitting element, and a semiconductor element electrically connected to the first electrode of the first light-emitting element are arranged in a matrix over a substrate, An insulating film is formed between one light-emitting element and the second light-emitting element, and the first light-emitting element includes a first electrode, a layer containing a first light-emitting substance, and a second electrode However, the second light-emitting element includes a third electrode, a layer containing a second light-emitting substance, and a fourth electrode in order from the substrate side. The first light emitting element and the semiconductor element are formed between the second light emitting element and the substrate, and the first electrode and the fourth electrode are translucent. A light emitting device comprising:   The light-emitting device according to claim 7, wherein the second electrode and the third electrode have a light-transmitting property and the insulating film is colored.   The light-emitting device according to claim 7, wherein the second electrode or the third electrode has a light-transmitting property and the insulating film is colored.   The light emission according to claim 5, wherein the colored insulating film is an organic resin in which metal particles, carbon particles, or black pigments are dispersed. apparatus.   11. The light-emitting element according to claim 1, wherein the first light-emitting element is an active matrix light-emitting element, and the second light-emitting element is a passive matrix light-emitting element. A light emitting device characterized by the above.   11. The light-emitting element according to claim 1, wherein the first light-emitting element is an active matrix light-emitting element, and the second light-emitting element is an area color light-emitting element. A light emitting device characterized.   13. The light-emitting device according to claim 1, wherein the first light-emitting element or the second light-emitting element is a light-emitting element that emits light from an organic compound.   14. The light-emitting device according to claim 1, wherein the semiconductor element is a thin film transistor, a MOS transistor, an organic transistor, or a diode. An electronic apparatus comprising the light emitting device according to claim 1.

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