JP2006184873A - Display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display which has a light shading film manufactured at a low cost without increasing the number of processes. <P>SOLUTION: This display has a monitor element to suppress the effects by the changes in temperature and over aging of the light emitting elements, and a TFT to drive the monitor. This TFT to drive the monitor do not overlap the monitor element. Further, it has a 1st light shading film overlapping the 1st electrode of the monitor element, and a 2nd light shading film overlapping the outer fringe of the 1st electrode. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device using a semiconductor element (an element using a semiconductor thin film). In particular, the present invention relates to a display device using an electroluminescence (EL) element and a thin film transistor (hereinafter referred to as “TFT”). Further, the present invention relates to an electronic device using the display device for a display portion.

  In recent years, so-called self-luminous display devices in which pixels are formed by light-emitting elements such as light-emitting diodes (LEDs) have attracted attention. As a light-emitting element used in such a self-luminous display device, an organic light-emitting diode (also referred to as an OLED (Organic Light Emitting Diode), an organic EL element, or an electroluminescence (EL) element) attracts attention. It has been used for organic EL displays and the like.

  An EL element has an electroluminescent layer between a pair of electrodes, and is a self-luminous type that emits light by passing a current between the electrodes. Therefore, the EL element has higher visibility than a liquid crystal display and does not require a backlight. This is advantageous in that the response speed is fast. The luminance of the light emitting element is controlled by the value of current flowing through the light emitting element.

  A light-emitting element has a property that its resistance value (internal resistance value) changes depending on the ambient temperature (hereinafter referred to as “environmental temperature”). Specifically, when the room temperature is a normal temperature, the resistance value decreases when the temperature is higher than normal, and the resistance value increases when the temperature is lower than normal. Therefore, in constant voltage driving, the current value increases to a higher brightness than the desired brightness when the temperature increases, and the current value decreases to a brightness lower than the desired brightness when the temperature decreases. In addition, light emitting elements used recently have the property that the current value decreases with time even when a predetermined voltage is applied.

Due to the properties of the light emitting element as described above, when the environmental temperature changes or changes with time occur, the luminance varies. In order to solve the problem of variation in luminance of the light emitting element due to the change in ambient temperature and the change with time, it has been proposed to provide a monitor element (see, for example, Patent Document 1). One electrode of the monitor element is connected to a constant current source and the input (input terminal) of the amplifier, and the output (output terminal) of the amplifier is connected to one electrode of the light emitting element provided in the pixel of the pixel portion. It is connected. With such a configuration, the magnitude of the current flowing through the light emitting element of the pixel is kept constant based on the temperature characteristics of the monitor element. Note that in this specification, “connected” includes not only a direct connection but also an electrical connection. Therefore, another element or wiring may be formed between them. In this specification, the term “overlap” includes not only the case where elements (for example, insulating films and wirings) constituting the display device are in direct contact with each other and overlapping, but also the case where they overlap with each other via another element. Shall be.
JP 2002-333861 A

  With the above structure, even when the temperature of the light emitting element (electroluminescent layer) changes, the magnitude of the current flowing through the light emitting element of the pixel can be kept constant. Therefore, even if the environmental temperature of the display device rises, the power consumption of the display device can be prevented from increasing, and the luminance can be kept constant.

  Since the monitor element is not used for displaying an image, it is necessary to shield the area where the monitor element is provided (monitor element unit) so that light generated from the monitor element does not leak. As a method of solving the light leakage, there is a method of providing a light shielding film. Further, there is a method in which an uneven portion is provided on the reflection surface of the cathode of the monitor element (the surface in contact with the light emitting layer side) to scatter the reflected light on the reflection surface of the cathode.

  A configuration example of the light shielding film provided in the monitor element portion will be described with reference to FIGS. FIG. 1 is a layout of the monitor element portion, and FIG. 2 is a cross-sectional structure diagram taken along the chain line A-A ′ of FIG. 1. 13 shows the same monitor element portion as FIG. 1, but the description of the first electrode 207 is omitted in the region indicated by reference numeral 212 for easy understanding of the position of the TFT for driving the monitor element. In the region indicated by reference numeral 213, the illustration of the current supply line 202, the light shielding film 214, and the drain electrode 215 is omitted.

  As shown in FIGS. 1, 2, and 13, in the monitor element portion, a control line 201 for applying a potential to the gate wiring of the TFT 211 that drives the monitor element, and a gate wiring 206 of the TFT provided in the light emitting element of the pixel portion In the region surrounded by, there are a monitor element composed of a first electrode (anode or cathode), an electroluminescent layer 208, and a second electrode (cathode or anode) 209, and a TFT for driving the monitor element, respectively. Is provided. A region 204 surrounded by a dotted line in FIGS. 1, 2, and 13 represents a region where a monitor element including an anode, an electroluminescent layer, and a cathode emits light. Further, the gate wiring 205 of the TFT for driving the monitor element overlaps the first electrode 207 of the monitor element portion. In addition, since the TFT 211 is formed in a region surrounded by the control line 201 and the gate wiring 206, and the gate electrode 205 of the TFT 211 is formed on the same layer as the light shielding film 203, the light shielding film 203 overlaps with the TFT 211. It is necessary to form so as not to become. For this reason, it is difficult to form the light shielding film 203 having a size and shape sufficient to shield light. As a result, light generated from the monitor element leaks from the gap between the TFT 211 and the light shielding film 203. Also, from a region corresponding to a gap between the current supply line 202 that connects the source region of the TFT that drives the monitor element and the constant current source and the control line 201 that applies a potential to the gate wiring of the TFT that drives the monitor element. Light leaks. In FIG. 2, reference numeral 210 is an interlayer insulating film, and 211 is an insulating film (referred to as a bank, partition, barrier, bank, etc.).

  This light leakage can be prevented by lowering the aperture ratio of the monitor element section, but considering the deterioration characteristics of the light emitting element, the aperture ratio of the monitor element section and the aperture ratio of the pixel section should be the same. Is desirable. Therefore, lowering the aperture ratio of the monitor element portion is not desirable for achieving the original purpose of compensating for the temperature and deterioration of the light emitting element in the pixel portion.

  An object of the present invention is to provide a display device in which a light-shielding film is formed without increasing the number of steps and without increasing the cost.

  The display device of the present invention includes a monitor element for suppressing an influence due to a temperature change and a change with time of the light emitting element, and a TFT for driving the monitor element, and the monitor element and the monitor element are driven. The TFTs for this purpose are provided in different regions. That is, the TFT for driving the monitor element is provided so as not to overlap the monitor element. In addition, the display device of the present invention includes a first light-shielding film provided so as to overlap with the first electrode of the monitor element, and a second light-shielding film overlapping with the outer edge portion of the first electrode. In the present specification, the “monitor element portion” refers to the entire region where the monitor element is provided.

  A display device including a light-emitting element to which the present invention can be applied is an active matrix type. As a method for emitting light emitted from the light emitting element, a bottom emission type or a double emission type can be applied.

  The first light shielding film is simultaneously formed under the same manufacturing conditions as the gate signal line of the monitor element and the gate signal line of the light emitting element provided in the pixel portion, and the second light shielding film is formed of the monitor element. They are formed simultaneously under the same manufacturing conditions as the source signal line of the element and the source signal line of the light emitting element provided in the pixel portion.

  The display device of the present invention includes a plurality of pixels, a source signal line driver circuit (source driver), and a gate signal line driver circuit (gate driver). Each of the plurality of pixels holds a light-emitting element, a first transistor that controls input of a video signal to the pixel, a second transistor that controls lighting or non-lighting of the light-emitting element, and a video signal. And a capacitor. Note that the capacitor is not necessarily provided, and the gate capacitor of the second transistor can be used instead.

  Further, the monitor element portion (region where the monitor element is provided) may be provided in the pixel portion, or may be provided in other regions. However, in order not to affect the display of the image and to place the monitor element portion and the light emitting element of the pixel portion in the same environment as much as possible, the monitor element portion should be provided close to a region other than the pixel portion. Is desirable.

  The number of monitor elements can be selected as appropriate. That is, only one monitor element may be provided, or a plurality of monitor elements may be provided. When only one monitor element is used, the current value to be supplied to the constant current source may be set to a current value to be supplied to the light emitting element of each pixel, so that power consumption can be reduced. In addition, when a plurality of monitor elements are provided, it is possible to average variations in characteristics for each monitor element.

  When color display is performed using a panel including a light-emitting element, an electroluminescent layer having a different emission wavelength band is preferably provided for each pixel. Typically, red (R), green (G), and blue (B It is preferable to provide an electroluminescent layer corresponding to each color. In this case, it is preferable to provide monitor elements corresponding to the respective colors of red, green, and blue so that the power supply voltage can be corrected for each color. In this case as well, a configuration may be adopted in which one monitor element is provided for each color, but a configuration in which a plurality of monitor elements are preferably provided for each color is preferable.

The structure of the invention related to the active matrix display device disclosed in this specification is as follows.
A pixel portion in which a plurality of pixels each having a light emitting element and a first thin film transistor for driving the light emitting element are provided in a matrix;
A monitor element having a first electrode, an electroluminescent layer formed on the first electrode, and a second electrode formed on the electroluminescent layer;
A second thin film transistor for driving the monitor element;
A constant current source for supplying a constant current to the monitor element;
An amplifier, and
The constant current source is electrically connected to one of a source and a drain of the second thin film transistor and an input of the amplifier,
The other of the source and the drain of the second thin film transistor is electrically connected to one electrode of the monitor element,
One electrode of the light emitting element is electrically connected to the output of the amplifier via the first thin film transistor,
The monitor element and the second thin film transistor are provided so as not to overlap each other.
A first light-shielding film is provided so as to overlap the first electrode of the monitor element;
A second light-shielding film is provided so as to overlap with an end portion of the first electrode of the monitor element.

Further, another invention relating to an active matrix display device disclosed in this specification includes:
A pixel portion in which a plurality of pixels each having a light emitting element and a first thin film transistor for driving the light emitting element are provided in a matrix;
A monitor element having a first electrode, an electroluminescent layer formed on the first electrode, and a second electrode formed on the electroluminescent layer; a second thin film transistor for driving the monitor element; Including a monitor element unit,
A constant current source for supplying a constant current to the monitor element;
An amplifier, and
The constant current source is electrically connected to one of a source and a drain of the second thin film transistor and an input of the amplifier,
The other of the source and the drain of the second thin film transistor is electrically connected to one electrode of the monitor element,
One electrode of the light emitting element is electrically connected to the output of the amplifier via the first thin film transistor,
In the monitor element section,
A first light-shielding film formed of the same material as the gate signal line;
An interlayer insulating film formed on the first light shielding film;
A second light-shielding film formed of the same material as the source signal line and formed on the interlayer insulating film;
And the monitor element formed on the interlayer insulating film and the second light shielding film,
The monitor element and the second thin film transistor are provided in different regions through the gate signal line,
A first light-shielding film is provided so as to overlap the first electrode of the monitor element via the interlayer insulating film;
A second light-shielding film is provided so as to overlap with an end portion of the first electrode of the monitor element.

  In the configuration of the invention described above, the second light-shielding film is annular.

  In the configuration of the invention described above, the display device is a bottom emission type or a double emission type.

  In the configuration of the invention described above, the amplifier is a voltage follower.

  In the above structure of the invention, the monitor element and the TFT for driving the monitor element are provided in the vicinity of the pixel portion.

  In the structure of the invention described above, the pixel portion includes a plurality of pixels that emit red, a plurality of pixels that emit green, and a plurality of pixels that emit blue, and drives the monitor element and the monitor element. The thin film transistor is provided for each emission color.

  In the above-described structure, the monitor element and the light-emitting element are EL elements.

  In the above-described structure, the monitor element and the light-emitting element are formed using the same material and in the same process.

  Another structure of the invention related to the display device disclosed in this specification is an EL television including the display device.

In addition, the structure of the invention related to a method for manufacturing an active matrix display device disclosed in this specification is as follows.
Form a base film on the substrate,
Forming a semiconductor layer on the base film;
Forming a gate insulating film on the semiconductor layer;
Forming a gate electrode on the gate insulating film and simultaneously forming a first light-shielding film;
A source region and a drain region are formed by adding impurities to the semiconductor layer using the gate electrode as a mask, and a thin film transistor for driving a monitor element is formed,
Forming an interlayer insulating film on the gate insulating film, the gate electrode, and the first light shielding film;
Forming a source electrode and a drain electrode connected to the source region and the drain region, respectively, and simultaneously forming a second light-shielding film;
A first electrode is formed so as to overlap the first light-shielding film through the interlayer insulating film, an electroluminescent layer is formed on the first electrode, and a second electrode is formed on the electroluminescent layer. By forming a monitor element on the interlayer insulating film,
The end of the first electrode overlaps the second light-shielding film in the previous period,
The monitor element is formed so as not to overlap a thin film transistor that drives the monitor element.

  The present invention is characterized in that, in a region where a monitor element is provided (monitor element portion), a region where the monitor element is provided and a region where a thin film transistor for driving the monitor element is provided are different from each other. . That is, the thin film transistor for driving the monitor element does not overlap with the monitor element. Then, a first light-shielding film is formed using a conductive film used for forming a gate electrode and a gate signal line of a TFT for driving the monitor element. Further, a second light-shielding film is formed using a conductive film used for forming the source signal line. By forming two light shielding films in this way, a highly reliable light shielding film can be formed without increasing the number of steps. In addition, a display device with high yield and reliability can be provided at low cost.

  The best mode for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below. Note that in structures of the present invention described below, the same portions or portions having similar functions are denoted by the same reference numerals in different drawings, and description thereof is not repeated.

(Embodiment 1)
In this embodiment mode, characteristics of the light shielding film provided in the monitor element portion will be described.

  FIG. 3 shows a layout diagram in the region where the monitor element is provided. FIG. 4A shows a cross-sectional structure diagram taken along the chain line A-A ′ in FIG. 3.

  The first light shielding film 301 is a conductive film formed of the same layer as the gate signal line 302 connected to the gate driver. The first light shielding film 301 and the gate signal line 302 are formed of the same layer as the gate wiring 303 of the TFT 310 for driving the monitor element. The first light shielding film 301 is provided so as to overlap with the first electrode 321 of the monitor element. The first light-shielding film 301 is provided so as not to overlap at least the gate signal line 302 in a region surrounded by the two gate signal lines 302 and the two current supply lines 312. The light shielding film 301 may be provided so as to overlap with the current supply line 312.

  The second light shielding film 311 is a conductive film formed of the same layer as the current supply line 312 that connects the source region of the TFT 310 that drives the monitor element and the constant current source. The second light shielding film 311 also functions as a drain electrode of the TFT 310. Further, the second light shielding film 311 and the current supply line 312 are formed of the same layer as the control line 313 for applying a potential to the gate wiring 303 of the TFT 310. The second light shielding film 311 has an annular shape and is provided so as to cover the outer periphery (outer edge) portion of the first electrode 321. By providing the second light shielding film 311 in this manner, it is possible to cover a region that is not covered with the first electrode 321 only by the first light shielding film 301. Reference numeral 324 denotes an insulating film (referred to as a bank, a partition, a barrier, a bank, or the like).

  Note that the first electrode 321 is one electrode for applying a potential to the electroluminescent layer 320 and functions as an anode or a cathode. 3A and 3B, a light-emitting region 322 indicated by a dotted line is a region where the light-emitting element emits light when a potential is applied to the first electrode 321 and the second electrode 323, respectively.

  In this embodiment mode, in the bottom-illuminated display device, a plurality of monitor elements and drive TFTs are arranged alternately for a plurality of pixels arranged in a matrix. In other words, the monitor element and the TFT for driving the monitor element are provided in different regions through the gate signal line. In addition, the first light shielding film 301 and the second light shielding film 311 overlap the first electrode 321 so that light emitted from the monitor element does not leak. With this structure, light emitted from the monitor element can be sufficiently blocked.

  In addition, the first light shielding film 301 and the second light shielding film 311 are formed in the same process as the wiring for forming the TFT 310 for driving the monitor element. For this reason, the light shielding film can be formed without increasing unnecessary costs and the number of processes.

  Here, a light-emitting element having a bottom emission structure (bottom emission method) provided in the pixel portion, which is formed over the same substrate as the monitor element portion, will be described with reference to FIG.

  As a material used for the first electrode 1302 functioning as an anode, a material having a high work function is preferably used. For example, a transparent conductive film such as an ITO (indium tin oxide) film or an indium zinc oxide (IZO) film can be used. An anode capable of transmitting light can be formed by using a conductive film having transparency. Note that the first electrode 1302 is connected to the TFT 1301.

In addition, as a material used for the second electrode 1304 functioning as a cathode, a material having a low work function (Al, Ag, Li, Ca, or an alloy thereof, MgAg, MgIn, AlLi, CaF ₂ , or calcium nitride) A metal film made of can be used. Thus, by using a metal film that reflects light, a cathode that does not transmit light can be formed. Reference numeral 1303 denotes an electroluminescent layer.

In this manner, light from the light emitting element provided in the pixel portion can be extracted to the lower surface as indicated by an arrow in FIG. In the case where a light-emitting element having a bottom emission structure provided in the pixel portion is used for a display device, the substrate 1300 is a light-transmitting substrate. In the case of providing an optical film, the substrate 1300 may be provided with an optical film.
(Embodiment 2)

  In this embodiment mode, a structure of a display device including a light-blocking film in the case where two interlayer insulating films are formed in a monitor element portion will be described with reference to FIG. In the present embodiment, only differences from the first embodiment will be described.

  In Embodiment Mode 1, since only one interlayer insulating film is formed as shown in FIG. 4A, the first electrode 321 is formed in contact with the second light-shielding film 311 over the interlayer insulating film 331. In contrast, in the present embodiment, two interlayer insulating films are formed. The outer edge (end) of the first electrode 321 overlaps the second light-shielding film 311 with the second-layer interlayer insulating film 332 interposed therebetween. Note that FIG. 4B illustrates an example in which the second light-shielding film 311 has an annular shape; however, the present invention is not limited to this. That is, in the case where the first electrode 321 and the second light shielding film 311 overlap with the second interlayer insulating film 332 interposed therebetween, the second light shielding film 311 is formed between the first light shielding film 301 and the gate wiring 302. It suffices to have a shape that at least shields the gap between them. Also in this embodiment mode, the region where the monitor element is provided and the region where the TFT for driving the monitor element are arranged so as not to overlap with each other; In addition, the second light-shielding film 311 enables a structure in which light does not leak from the display device to the outside.

(Embodiment 3)
In this embodiment mode, a manufacturing process of a monitor element portion of a display device will be described. Note that a thin film transistor or a light-emitting element provided in the pixel portion of the display device may be formed using the same manufacturing conditions and manufacturing steps as those of the thin film transistor and the monitor element provided in the monitor element portion. The description is omitted here.

  5 and 6 are cross-sectional views taken along the chain line BB ′ of FIG. 8 which is a top view. First, as illustrated in FIG. 5A, the base film 102 is formed over the insulating substrate 101. As the insulating substrate 101, 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. A substrate made of a synthetic resin having flexibility such as plastic generally has a lower heat-resistant temperature than the above-mentioned substrate, but can be used as long as it can withstand the processing temperature in the manufacturing process. It is. Alternatively, the surface of the insulating substrate 101 may be polished and planarized by a CMP method or the like.

  As a method for forming the base film 102, a known method such as a CVD method typified by a plasma CVD method or a low-pressure CVD method, or a sputtering method may be used. Further, as the base film, a single-layer structure using any one of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, and a silicon nitride oxide film may be used, or a structure in which these layers are appropriately stacked may be used. Note that in this specification, silicon oxynitride refers to a substance having a higher oxygen composition ratio than nitrogen, and can also be referred to as silicon oxide containing nitrogen. In this specification, silicon nitride oxide refers to a substance having a higher nitrogen composition ratio than oxygen, and can also be referred to as silicon nitride containing oxygen. In this embodiment mode, a silicon nitride oxide film and a silicon oxynitride film are sequentially stacked as the base film.

  Next, the semiconductor film 103 is formed over the base film 102. An amorphous semiconductor film may be formed as the semiconductor film 103, but a microcrystalline semiconductor film or a crystalline semiconductor film may be formed. There is no limitation on the material of the semiconductor film, but silicon or silicon germanium is preferably used. In this embodiment mode, an amorphous silicon film is formed. Note that a step of removing hydrogen contained in the semiconductor film may be performed after the semiconductor film is formed.

  In addition, when the base film 102 and the semiconductor film 103 are formed, if the interface between the base film 102 and the semiconductor film 103 is not exposed to the atmosphere, contamination of the interface can be prevented, and characteristics of the manufactured TFT can be prevented. Can be reduced. In this embodiment mode, the base film 102 and the semiconductor film 103 are successively formed using the plasma CVD method without being exposed to the atmosphere.

  Next, a crystalline semiconductor film is formed from the semiconductor film 103 by a known method (laser crystallization method, thermal crystallization method, thermal crystallization method using an element that promotes crystallization such as nickel). Here, after crystallization, an impurity imparting p-type conductivity such as boron (B) is doped on the entire surface of the crystalline semiconductor film, and channel doping is performed on a region to be a channel formation region of the TFT. The threshold voltage may be controlled. Note that although a crystalline semiconductor film obtained by crystallizing the semiconductor film 103 is used in this embodiment mode, an amorphous semiconductor film can be used instead of the crystalline semiconductor film.

  Next, as shown in FIG. 5B, the crystalline semiconductor film is patterned to form a crystalline semiconductor layer 104 (island semiconductor layer). Note that FIG. 8A illustrates a top view of the crystalline semiconductor layer 104. In this specification, “patterning” refers to etching into a desired shape.

  Next, a gate insulating film 105 is formed over the patterned crystalline semiconductor layer 104. The gate insulating film 105 may have a single-layer structure using any one of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, and a silicon nitride oxide film, or a structure in which these are stacked as appropriate.

  Next, as shown in FIGS. 5C and 8B, a gate wiring 106 (gate electrode) is formed on the gate insulating film 105 and simultaneously connected to the first light shielding film 151 and the gate driver. A gate signal line 160 is formed. Note that the first light-blocking film 151 is formed so as to overlap with the first electrode 110 manufactured in a later step. Further, the first light shielding film 151 is provided in the monitor element portion, and is not provided in the light emitting element of the pixel portion. As a material for the gate wiring 106 and the first light-blocking film 151, a material containing at least one of aluminum, molybdenum, titanium, and carbon, or a plurality of types may be used. At this time, the composition ratio of molybdenum or titanium is preferably 7.0 to 20% by atom.

  Next, using the gate wiring 106 as a mask, the crystalline semiconductor layer 104 is doped with an impurity imparting p-type conductivity such as boron (B). By this step, the source region and drain region of the TFT can be formed in a self-aligned manner. In this embodiment mode, a low concentration impurity region (LDD region) is formed between a channel formation region of TFT and a source region and a drain region by a known doping method. However, a low concentration impurity region is provided. There may be no configuration.

  In addition, after the doping, heat treatment, intense light irradiation, or laser light irradiation may be performed in order to activate the impurity element doped in the impurity region. Accordingly, not only activation of the impurity element but also plasma damage to the gate insulating film 105 and plasma damage to the interface between the gate insulating film 105 and the crystalline semiconductor layer 104 can be recovered.

  Next, as illustrated in FIG. 5D, a first interlayer insulating film 107 is formed over the gate insulating film 105 and the gate wiring 106. In this embodiment, a silicon nitride oxide film and a silicon oxynitride film are stacked in this order.

  After the formation of the first interlayer insulating film 107, heat treatment is performed at 300 to 550 ° C. (more preferably 400 to 500 ° C.) for 1 to 12 hours in a nitrogen atmosphere, and the patterned crystalline semiconductor layer 104 (semiconductor) The step of hydrogenating the layer) is preferably carried out. Through this step, dangling bonds in the semiconductor layer can be terminated by hydrogen contained in the first interlayer insulating film 107. In this embodiment, heat treatment is performed at 410 ° C. for 1 hour.

  Next, contact holes are formed in the first interlayer insulating film 107 so as to reach the source region and the drain region of the TFT. The shape of the contact hole is preferably a tapered shape.

  Next, as shown in FIGS. 6A and 8C, the wiring 108 (current supply line) is formed so as to cover the contact hole, and at the same time, the second light shielding film 152 and the control line 154 are formed. The wiring 108 functions as a source electrode (or current supply line), and the second light shielding film 152 functions not only as light shielding but also as a drain electrode. 8C, the second light-shielding film 152 includes at least the first light-shielding film 151 and the gate signal line 160 over the first light-shielding film 151 when viewed from above. It is provided so as to overlap with the region between them, and has an annular shape. The second light-shielding film 152 is provided on the monitor element and is not provided on the light-emitting element of the pixel portion.

  Examples of materials for the wiring 108 and the second light shielding film 152 include Ag, Au, Cu, Ni, Pt, Pd, Ir, Rh, W, Al, Ta, Mo, Cd, Zn, Fe, Ti, Zr, Ba, and the like. Or a metal nitride thereof, or a metal nitride thereof, or a semiconductor material such as Si or Ge. Moreover, it is good also as these laminated structure. In this embodiment mode, titanium (Ti) is formed to a thickness of 100 nm, an alloy of aluminum and silicon (Al—Si) is formed to a thickness of 700 nm, titanium (Ti) is formed to a thickness of 200 nm, and is patterned into a desired shape.

  Next, as shown in FIGS. 6B and 8D, the first electrode 110 is formed in contact with the first interlayer insulating film 107 and the second light-shielding film 152. As shown in the top view of FIG. 8D, the first electrode 110 is provided so as to be entirely disposed on the first light-shielding film 151 when viewed from above. The outer edge portion of the first electrode 110 is in contact with the upper surface and side surfaces of the second light shielding film 152.

  In this embodiment mode, the first electrode 110 is formed using a light-transmitting film in order to extract light from the light-emitting element in the pixel portion from the first electrode 110 side. As the first electrode 110, indium tin oxide containing silicon oxide (also referred to as indium tin oxide containing silicon oxide; hereinafter referred to as “ITSO”), zinc oxide, tin oxide, indium oxide, or the like can be used. . A transparent conductive film such as an indium zinc oxide alloy in which 2 to 20 atomic% of zinc oxide (ZnO) is mixed with indium oxide can also be used. In addition to the transparent conductive film, a titanium nitride film or a titanium film may be used. In this case, after forming the transparent conductive film, the titanium nitride film or the titanium film is formed to a thickness that allows light to pass therethrough (preferably about 5 to 30 nm). In this embodiment, an ITSO film is formed to 110 nm as the first electrode 110.

  Further, the first electrode 110 may be cleaned by polishing with a CMP method or a polyvinyl alcohol-based porous body so that the surface thereof is planarized. Further, after polishing using the CMP method, the surface of the first electrode 110 may be subjected to ultraviolet irradiation, oxygen plasma treatment, or the like.

  Note that in this embodiment, the process for manufacturing a p-channel TFT has been described. However, the present invention can also be applied to manufacturing an n-channel TFT by doping an impurity imparting n-type conductivity into the crystalline semiconductor layer 104 using the gate electrode as a mask. The present invention can also be applied to the case where a p-channel TFT and an n-channel TFT are formed over the same substrate.

  The TFT may have a single gate structure in which one channel formation region is formed in the crystalline semiconductor layer 104, a double gate structure in which two channel formation regions are formed, or a triple gate structure in which three channel formation regions are formed. The thin film transistor in the peripheral driver circuit region may have a single gate structure, a double gate structure, or a triple gate structure.

  In addition to the TFT manufacturing method described in this embodiment mode, a top gate type (planar type), a bottom gate type (reverse stagger type), or a channel formation region is disposed above and below a gate insulating film. The present invention can also be applied to a dual gate type or other structure having two gate electrodes.

  Next, as illustrated in FIG. 6C, an insulating film 111 (referred to as a bank, a partition, a barrier, a bank, or the like) is formed so as to cover the end portion of the first electrode 110 and the TFT.

  As the insulating film 111, silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, aluminum nitride, aluminum oxynitride, and other inorganic insulating materials, acrylic acid, methacrylic acid, and derivatives thereof, polyimide, aromatic Inorganic siloxanes containing Si—O—Si bonds among silicon, oxygen, and hydrogen compounds formed from heat-resistant polymers such as aromatic polyamides, polybenzimidazoles, or siloxane-based materials as starting materials It is possible to use an organic siloxane-based insulating material in which hydrogen is substituted with an organic group such as a methyl group or a phenyl group. You may form using photosensitive and non-photosensitive materials, such as an acryl and a polyimide. In this embodiment mode, the insulating film 111 is formed using photosensitive polyimide so as to have a thickness of 1.5 μm in a flat region.

  In addition, the insulating film 111 preferably has a shape in which the radius of curvature continuously changes, and the coverage of the electroluminescent layer (a layer containing an organic compound) formed on the insulating film 111 and the second electrode can be improved. .

  In order to further improve the reliability, heat treatment may be performed before forming the electroluminescent layer. By the heat treatment, moisture contained in and attached to the first electrode 110 and the insulating film 111 is preferably released.

  Next, as illustrated in FIG. 10, the electroluminescent layer 112 is formed over the first electrode 110. Note that FIG. 10 corresponds to a cross-sectional view taken along chain line B-B ′ in FIGS. 3 and 8D. Although only one monitor element is shown in FIG. 10, in this embodiment, electric field electrodes corresponding to each color of red (R), green (G), and blue (B) are separately formed. In this embodiment mode, a material that emits red (R), green (G), and blue (B) light is selectively formed as the electroluminescent layer 112 by an evaporation method using an evaporation mask. The materials that emit red (R), green (G), and blue (B) light can be selectively formed by a vapor deposition method using a vapor deposition mask or a droplet discharge method. In the case of the droplet discharge method, there is an advantage that RGB can be separately applied without using a mask. In this embodiment mode, materials that emit red (R), green (G), and blue (B) light are formed by an evaporation method.

  A known organic light emitting material or inorganic light emitting material can be used for the electroluminescent layer. The organic light emitting material includes a low molecular (monomer) material and a high molecular (polymer) material, either of which may be used. The structure of the electroluminescent layer may be a stacked structure or a single layer structure by freely combining a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, or the like.

  Note that before the electroluminescent layer is deposited, it is preferable to perform heat treatment in an atmosphere containing an inert gas as a main component, an oxygen concentration of 5% or less, and a water concentration of 1% or less to remove moisture and the like. . In this embodiment, heat treatment is performed at 300 ° C. for 1 hour.

Next, a second electrode 113 made of a conductive film is formed over the electroluminescent layer 112. Note that when the first electrode 110 functions as an anode, the second electrode 113 functions as a cathode, and when the first electrode 110 functions as a cathode, the second electrode 113 functions as an anode. Also,
As a material for the second electrode 113, a material having a low work function (Al, Ag, Li, Ca, or an alloy thereof, MgAg, MgIn, AlLi, CaF ₂ , or calcium nitride) may be used.

  Through the above steps, a monitor element including the first electrode 110, the electroluminescent layer 112, and the second electrode 113 is formed. A region where the monitor element emits light is represented by a light emitting region 153 in FIG. The light emitting region 153 is shielded by the first light shielding film 151 and the second light shielding film 152 so that light does not leak from the substrate side.

  In the display device illustrated in FIG. 10, light emitted from the monitor element passes through a film formed between the substrate 101 and the first electrode 110 and is emitted in the direction of the arrow from the first electrode 110 side. The first light shielding film 151 and the second light shielding film 152 are shielded from light.

  In addition, it is effective to provide a passivation film so as to cover the second electrode 113. As the passivation film, silicon nitride, silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum nitride, aluminum oxynitride (AlON) having an oxygen content higher than the nitrogen content, and nitriding having a nitrogen content higher than the oxygen content The insulating film includes aluminum oxide (AlNO), aluminum oxide, diamond-like carbon (DLC), or a nitrogen-containing carbon film (CN), and a single layer or a combination of the insulating films can be used. In addition, a skeleton structure is formed by a bond of silicon (Si) and oxygen (O), and at least one of a material containing at least hydrogen as a substituent, or fluorine, an alkyl group, or an aromatic hydrocarbon as a substituent. You may use the material which has.

  At this time, it is preferable to use a film with good coverage as the passivation film, and it is effective to use a carbon film, particularly a DLC film. Since the DLC film can be formed in a temperature range from room temperature to 100 ° C., it can be easily formed over the electroluminescent layer 112 having low heat resistance. In addition, the DLC film has a high blocking effect against oxygen and can suppress oxidation of the electroluminescent layer 112. Therefore, the problem that the electroluminescent layer 112 is oxidized during the subsequent sealing step can be prevented.

  Next, the substrate 101 on which the light emitting element and the monitor element are formed and the sealing substrate are fixed with a sealing material, and the light emitting element and the monitor element are sealed. Since intrusion of moisture from the cross section is blocked by the sealing material, deterioration of the light emitting element can be prevented and the reliability of the display device is improved. Note that a region surrounded by the sealing material may be filled with a filler, or nitrogen or the like may be sealed by sealing in a nitrogen atmosphere. Further, the filler can be dropped in a liquid state and filled in the display device. Since this embodiment is a bottom emission type, it is not necessary to use a light-transmitting filler. However, in the case of a structure in which light is extracted through the filler, a light-transmitting material is used. It is necessary to form a filler. As an example of the filler, visible light curing, ultraviolet curing, or thermosetting epoxy resin can be given. Through the above steps, a display device having a light-emitting element is completed.

  In addition, as a sealing material, ultraviolet curable resin, thermosetting resin, silicone resin, epoxy resin, acrylic resin, polyimide resin, phenol resin, PVC (polyvinyl chloride), PVB (polyvinyl butyral), or EVA (ethylene vinyl acetate). It is possible to use. Further, the sealing material may be a filler (a rod-like or fiber-like spacer) or a spherical spacer added.

  Further, it is preferable to install a desiccant in the display panel in order to prevent deterioration of the element due to moisture. In this embodiment mode, a desiccant is provided in a concave portion formed in the sealing substrate so as to surround the pixel portion and the monitor element portion, and the thickness is not hindered. In addition, by installing a desiccant in the region corresponding to the gate wiring layer, the water absorption area can be increased, and the water absorption effect is high. Further, since the desiccant is formed on the gate wiring layer that does not emit light directly, the light extraction efficiency of the pixel portion is not lowered.

  Note that in this embodiment, the case where a light-emitting element is sealed with a glass substrate is described; however, the sealing process is a process for protecting the light-emitting element from moisture and is mechanically sealed with a cover material. Or a method of encapsulating with a thermosetting resin or an ultraviolet light curable resin, or a method of encapsulating with a thin film having a high barrier ability such as a metal oxide or nitride. As the cover material, glass, ceramics, plastic, or metal can be used. However, when light is emitted to the cover material side, it must be translucent. In addition, the cover material and the substrate on which the light emitting element is formed are bonded together using a sealing material such as a thermosetting resin or an ultraviolet light curable resin, and the resin is cured by heat treatment or ultraviolet light irradiation treatment to form a sealed space. Form. It is also effective to provide a hygroscopic material typified by barium oxide in this sealed space. This hygroscopic material may be provided in contact with the sealing material, or may be provided on the partition wall or in the peripheral portion so as not to block light from the light emitting element. Further, the space between the cover material and the substrate on which the light emitting element is formed can be filled with a thermosetting resin or an ultraviolet light curable resin. In this case, it is effective to add a moisture absorbing material typified by barium oxide in the thermosetting resin or the ultraviolet light curable resin.

  Further, a glass substrate or a plastic substrate is used as the cover material. As the plastic substrate, polyimide, polyamide, acrylic resin, epoxy resin, PES (polyethylene sulfide), PC (polycarbonate), PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) may be used in the form of a plate or film. it can.

  The sealed space is filled with a dry inert gas. A small amount of moisture is removed from the inner sealed space surrounded by the sealing material with a desiccant and is sufficiently dried. As the desiccant, it is possible to use a substance that absorbs moisture by chemical adsorption, such as an oxide of an alkaline earth metal such as calcium oxide or barium oxide. As another desiccant, a substance that adsorbs moisture by physical adsorption, such as zeolite or silica gel, may be used.

  Further, if necessary, on the light emission surface of the light emitting element, optical films such as a polarizing plate or a circular polarizing plate (including an elliptical polarizing plate), a retardation plate (λ / 4 plate, λ / 2 plate), a color filter, etc. A film may be provided as appropriate. Further, an antireflection film may be provided on the polarizing plate or the circularly polarizing plate. For example, anti-glare treatment that diffuses reflected light due to surface irregularities and can reduce reflection can be performed. Moreover, you may perform the anti-reflection process which heat-processes to a polarizing plate or a circularly-polarizing plate. Thereafter, a hard coat treatment may be applied to protect from external impacts.

(Embodiment 4)
In this embodiment, a structure of a display device including a light-emitting element provided in a pixel portion and a monitor element provided in a monitor element portion will be described with reference to FIGS. The display device in this embodiment includes a gate driver 2107, a source driver 2108, and a pixel portion 2109. In addition, a monitor element portion 2110 provided in the vicinity of the pixel portion 2109 is provided. The monitor element portion 2110 is provided for three columns corresponding to each color of RGB. In each column, rows in which monitor elements are provided and rows in which TFTs for driving the monitor elements are provided are alternately arranged. That is, the number of the monitor elements and the TFTs for driving the monitor elements are respectively provided corresponding to half of one column of the light emitting elements of the pixel portion provided in a matrix. Note that a TFT for driving the monitor element may be either an n-channel TFT or a p-channel TFT. In this embodiment mode, a p-channel TFT is used.

  In the display device described in this embodiment, the monitor element provided in the monitor element portion 2110 and the light-emitting element provided in the pixel portion are provided over the same substrate. In other words, the light-emitting element and the monitor element are manufactured in the same process under the same manufacturing conditions, and approximately the same characteristics can be obtained with respect to changes in environmental temperature and changes with time. In addition, since the aperture ratios of the light emitting element and the monitor element portion are approximately the same, they have the same deterioration characteristics.

  The constant current source 2201a is connected to one electrode (anode) of the monitor element 2202a and the non-inverting input terminal of the voltage follower circuit 2203a. The other electrode (cathode) of the monitor element 2202a is connected to the ground potential. The output terminal of the voltage follower circuit 2203a is connected to one electrode of the light emitting element through a TFT for driving the light emitting element provided in the pixel portion 2109.

  A pixel connected to the signal line S1 emits R light, a pixel connected to the signal line S2 emits G light, and a pixel connected to the signal line S3 emits B light. And The constant current source 2201a supplies current to the monitor element 2202a, the voltage follower circuit 2203a detects the potential of the anode of the monitor element 2202a, and sets this potential to the power supply line V1. The constant current source 2201b supplies current to the monitor element 2202b, the voltage follower circuit 2203b detects the potential of the anode of the monitor element 2202b, and sets this potential to the power supply line V2. The constant current source 2201c supplies current to the monitor element 2202a, and the voltage follower circuit 2203c detects the potential of the anode of the monitor element 2202c, and sets this potential to the power supply line V3. By having such a configuration, a potential can be set for each of RGB. Therefore, even when the temperature characteristics and the degree of deterioration differ depending on the EL material for each RGB, a desired potential can be set for each light emitting element for each color, and the power supply potential can be corrected for each RGB.

  In the present embodiment, one electrode of the monitor element connected to the constant current source has been described as an anode (anode), but may be a cathode (cathode). In this embodiment, the cathode, which is the other electrode of the monitor element, is set to the ground potential. However, the present invention is not limited to this configuration.

(Embodiment 5)
In this embodiment, an example of a light-emitting display panel is described with reference to FIGS. FIG. 12A is a top view of a panel in which a space between a first substrate and a second substrate is sealed with a first sealant 1205 and a second sealant 1206. FIG. ) Corresponds to cross-sectional views taken along lines AA ′ and BB ′ in FIG.

  In FIG. 12A, 1202 indicated by a dotted line is a pixel portion, 1230 is a monitor element portion, and 1203 is a scanning line (gate line) drive circuit. In this embodiment, the pixel portion 1202, the scan line driver circuit 1203, and the connection region 1210 are in a region sealed with a first sealant and a second sealant. Reference numeral 1201 denotes a signal line (source line) drive circuit, and a chip-like signal line drive circuit is provided on the first substrate 1200. As the first sealing material, it is preferable to use a highly viscous epoxy resin containing a filler. As the second sealing material, it is preferable to use an epoxy resin having a low viscosity. The first sealing material 1205 and the second sealing material 1206 are preferably materials that do not transmit moisture and oxygen as much as possible.

Further, a desiccant may be provided between the pixel portion 1202 and the sealant 1205. Further, in the pixel portion, a desiccant may be provided on the scan line or the signal line. As the desiccant, it is preferable to use a substance that adsorbs water (H ₂ O) by chemical adsorption such as an alkaline earth metal oxide such as calcium oxide (CaO) or barium oxide (BaO). However, the present invention is not limited to this, and a substance that adsorbs water by physical adsorption such as zeolite or silica gel may be used.

  In addition, the resin can be fixed to the second substrate 1204 in a state where a highly moisture-permeable resin contains a granular material of a desiccant. Further, instead of a highly moisture-permeable resin, an inorganic substance such as a siloxane polymer, polyimide, PSG (phosphorus glass), or BPSG (phosphorus glass) may be used.

  Further, a desiccant may be provided in a region overlapping with the scanning line. Furthermore, you may fix to the 2nd board | substrate in the state which included the granular substance of the desiccant in resin with high moisture permeability. By providing these desiccants, it is possible to suppress the intrusion of moisture into the light emitting element and the deterioration due to it without reducing the aperture ratio. For this reason, it is possible to suppress variations in deterioration of the light emitting elements in the peripheral portion and the central portion of the pixel portion 1202.

  Reference numeral 1210 denotes a connection wiring region for transmitting signals input to the signal line driver circuit 1201 and the scanning line driver circuit 1203. The connection wiring 1208 is connected from an FPC (flexible printed wiring) 1209 serving as an external input terminal. Receive video signals and clock signals.

  Next, a cross-sectional structure will be described with reference to FIG. A driver circuit and a pixel portion are formed over the first substrate 1200, and includes a plurality of semiconductor elements typified by TFTs. A signal line driver circuit 1201 and a pixel portion 1202 are shown as driver circuits. Note that as the signal line driver circuit 1201, a CMOS circuit in which an n-channel TFT 1221 and a p-channel TFT 1222 are combined is formed.

  In this embodiment mode, a scanning line driver circuit and a TFT of a pixel portion are formed over the same substrate. For this reason, the volume of the light emitting display device can be reduced.

  The pixel portion 1202 is formed of a plurality of pixels including a switching TFT 1211, a driving TFT 1212, and a first pixel electrode (anode) 1213 made of a light-transmitting conductive film electrically connected to the drain thereof. The

  In addition, insulators (called banks, partition walls, barriers, banks, or the like) 1214 are formed at both ends of the first pixel electrode (anode) 1213. In order to improve the coverage (coverage) of the film formed over the insulator 1214, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 1214. The surface of the insulator 1214 may be covered with a protective film formed of an aluminum nitride film, an aluminum nitride oxide film, a thin film containing carbon as its main component, or a silicon nitride film. Further, by using an organic material obtained by dissolving or dispersing a material that absorbs visible light, such as a black pigment or a dye, as the insulator 1214, stray light from a light-emitting element to be formed later can be absorbed. As a result, the contrast of each pixel is improved.

  Further, an organic compound material is deposited on the first pixel electrode (anode) 1213 to selectively form the electroluminescent layer 1215. Further, a second pixel electrode (cathode) 1216 is formed on the electroluminescent layer 1215.

  In this manner, a light emitting element 1217 including the first pixel electrode (anode) 1213, the electroluminescent layer 1215, and the second pixel electrode (cathode) 1216 is formed. The light emitting element 1217 emits light toward the first substrate 1200 side.

  In addition, a protective film 1218 is formed to seal the light emitting element 1217. The protective film is composed of, for example, a laminate of a first inorganic insulating film, a stress relaxation film, and a second inorganic insulating film. Next, the protective film 1218 and the second substrate 1204 are bonded with the first sealant 1205 and the second sealant 1206. Note that the second sealant is preferably dropped using a device for dropping the sealant. After the sealing material is dropped or discharged from the dispenser to apply the sealing material onto the active matrix substrate, the second substrate and the active matrix substrate are bonded together in a vacuum and then cured by ultraviolet curing. it can.

  Note that an antireflection film 1226 is provided on the surface of the second substrate 1204 to prevent external light from being reflected by the substrate surface. One or both of a polarizing plate and a retardation plate may be provided between the second substrate and the antireflection film. By providing the retardation plate and the polarizing plate, it is possible to prevent external light from being reflected by the pixel electrode 1213. Note that the first pixel electrode 1213 and the second pixel electrode 1216 are formed using a light-transmitting conductive film or a semi-transparent conductive film (characteristic that transmits about half of the irradiated light). When the interlayer insulating film 1214 is formed using a material that absorbs visible light or an organic material in which a material that absorbs visible light is dissolved or dispersed, each pixel electrode does not reflect external light. In addition, a polarizing plate may not be used.

  The connection wiring 1208 and the FPC 1209 are electrically connected by an anisotropic conductive film or an anisotropic conductive resin 1227. Furthermore, it is preferable that the connection portion between each wiring layer and the connection terminal is sealed with a sealing resin. With this structure, moisture from the cross section can be prevented from entering and deteriorating the light emitting element.

  Note that a space filled with an inert gas such as nitrogen gas may be provided between the second substrate 1204 and the protective film 1218 instead of the second sealant 1206. It is possible to enhance prevention of moisture and oxygen from entering.

  Further, a colored layer can be provided between the second substrate and the polarizing plate. In this case, a full color display can be performed by providing a light emitting element capable of emitting white light in the pixel portion and separately providing a colored layer showing RGB. Further, full color display can be performed by providing a light emitting element capable of emitting blue light in the pixel portion and separately providing a color conversion layer or the like. Furthermore, each pixel portion, a light emitting element that emits red, green, and blue light can be formed, and a colored layer can be used. Such a display module has a high color purity of each RGB and enables high-definition display.

  Alternatively, the light-emitting display module may be formed using one of the first substrate 1200 and the second substrate 1204, or a substrate such as a film or resin. When sealing is performed without using the counter substrate in this manner, the weight, size, and thickness of the display device can be improved.

  Further, an IC chip such as a controller, a memory, and a pixel driver circuit may be provided on the surface or end of an FPC (flexible printed wiring) 1209 that serves as an external input terminal to form a light emitting display module.

  This embodiment can be combined with any of Embodiments 1 to 4 as appropriate.

(Embodiment 6)
The display device of the present invention can be used for display portions of various electronic devices. In particular, it is desirable to use the display device of the present invention for mobile devices that are required to be thin and light.

  As electronic devices in which the display device described in any of the above embodiments is incorporated in a housing, a television device (also simply referred to as a TV, a television, or a television receiver), a camera (a video camera, a digital camera, or the like), a goggle-type display , Navigation system, sound reproduction device (car audio, audio component, etc.), computer, game device, portable information terminal (mobile computer, mobile phone, portable game machine, electronic book, etc.), image reproduction device provided with recording medium (Specifically, a device having a display capable of playing back a recording medium such as a DVD (digital versatile disc), an HD DVD (High Definition DVD), a Blu-ray Disc (Blu-ray Disc), and the like) Display section Such as electrical appliances with, and the like. A specific example of the electronic device is illustrated in FIG.

  A portable information terminal illustrated in FIG. 9A includes a main body 9201, a display portion 9202, and the like. As the display portion 9202, the display portion shown in Embodiment Modes 1 to 5 can be applied. By using the display device which is one embodiment of the present invention, a highly reliable portable information terminal can be provided at low cost.

  A digital video camera shown in FIG. 9B includes a display portion 9701, a display portion 9702, and the like. As the display portion 9701, the display portion described in Embodiment Modes 1 to 5 can be applied. By using the display device which is one embodiment of the present invention, a highly reliable digital video camera can be provided at low cost.

  A portable terminal illustrated in FIG. 9C includes a main body 9101, a display portion 9102, and the like. The display portion 9102 can be any of those shown in Embodiment Modes 1 to 5. By using the display device which is one embodiment of the present invention, a highly reliable portable terminal can be provided at low cost.

  A portable television device shown in FIG. 9D includes a main body 9301, a display portion 9302, and the like. As the display portion 9302, any of those shown in Embodiment Modes 1 to 5 can be applied. By using the display device which is one embodiment of the present invention, a highly reliable portable television device can be provided at low cost. Such a television device can be widely applied from a small one mounted on a portable terminal such as a cellular phone to a medium-sized one that can be carried and a large one (for example, 40 inches or more). .

  A portable computer shown in FIG. 9E includes a main body 9401, a display portion 9402, and the like. As the display portion 9402, one shown in Embodiment Modes 1 to 5 can be applied. By using the display device which is one embodiment of the present invention, a portable computer having high reliability can be provided at low cost.

  A television device illustrated in FIG. 9F includes a main body 9501, a display portion 9502, and the like. As the display portion 9502, any of those shown in Embodiment Modes 1 to 5 can be applied. By using the display device which is one embodiment of the present invention, a highly reliable television device can be provided at low cost.

  Among the electronic devices listed above, those using a secondary battery can extend the usage time of the electronic device as much as power consumption is reduced, and can save the trouble of charging the secondary battery.

  In addition to the electronic devices described above, the projector can be used for a front or rear projector.

  As described above, the applicable range of the present invention is so wide that it can be used for electronic devices in various fields.

Monitor pixel layout (comparative example) Cross-sectional structure of monitor pixel (comparative example) Layout diagram of monitor pixel of the present invention Cross-sectional structure diagram of monitor pixel of the present invention The figure explaining the manufacturing process of the monitor element of this invention The figure explaining the manufacturing process of the monitor element of this invention The figure explaining the light emission direction in the display apparatus of this invention The top view explaining the manufacturing process of the monitor element of this invention FIG. 11 is a diagram showing an electronic device including the display device of the invention. Cross-sectional structure diagram of the monitor element of the present invention The figure showing the relationship between the pixel part of the display apparatus of this invention, and a monitor element part Top and cross-sectional views illustrating a structure of a display device of the present invention Monitor pixel layout (comparative example)

Explanation of symbols

110 First electrode 112 Electroluminescent layer 113 Second electrode 151 First light shielding film 152 Second light shielding film 153 Light emitting region

Claims (10)

A pixel portion in which a plurality of pixels each having a light emitting element and a first thin film transistor for driving the light emitting element are provided in a matrix;
A monitor element having a first electrode, an electroluminescent layer formed on the first electrode, and a second electrode formed on the electroluminescent layer;
A second thin film transistor for driving the monitor element;
A constant current source for supplying a constant current to the monitor element;
An amplifier, and
The constant current source is electrically connected to one of a source and a drain of the second thin film transistor and an input of the amplifier,
The other of the source and the drain of the second thin film transistor is electrically connected to one electrode of the monitor element,
One electrode of the light emitting element is electrically connected to the output of the amplifier via the first thin film transistor,
The monitor element and the second thin film transistor are provided so as not to overlap each other.
A first light-shielding film is provided so as to overlap the first electrode of the monitor element;
An active matrix display device, wherein a second light-shielding film is provided so as to overlap with an end portion of the first electrode of the monitor element. A pixel portion in which a plurality of pixels each having a light emitting element and a first thin film transistor for driving the light emitting element are provided in a matrix;
A monitor element having a first electrode, an electroluminescent layer formed on the first electrode, and a second electrode formed on the electroluminescent layer; a second thin film transistor for driving the monitor element; Including a monitor element unit,
A constant current source for supplying a constant current to the monitor element;
An amplifier, and
The constant current source is electrically connected to one of a source and a drain of the second thin film transistor and an input of the amplifier,
The other of the source and the drain of the second thin film transistor is electrically connected to one electrode of the monitor element,
One electrode of the light emitting element is electrically connected to the output of the amplifier via the first thin film transistor,
In the monitor element section,
A first light-shielding film formed of the same material as the gate signal line;
An interlayer insulating film formed on the first light shielding film;
A second light-shielding film formed of the same material as the source signal line and formed on the interlayer insulating film;
And the monitor element formed on the interlayer insulating film and the second light shielding film,
The monitor element and the second thin film transistor are provided in different regions through the gate signal line,
A first light-shielding film is provided so as to overlap the first electrode of the monitor element via the interlayer insulating film;
An active matrix display device, wherein a second light-shielding film is provided so as to overlap with an end portion of the first electrode of the monitor element.   3. The active matrix display device according to claim 1, wherein the second light shielding film is annular.   4. The active matrix display device according to claim 1, wherein the display device is a bottom emission type or a dual emission type. 5.   5. The active matrix display device according to claim 1, wherein the amplifier is a voltage follower.   6. The active matrix display device according to claim 1, wherein the monitor element and a thin film transistor that drives the monitor element are provided in proximity to the pixel portion.   7. The monitor element and the monitor element according to claim 1, wherein the pixel unit includes a plurality of pixels that emit red, a plurality of pixels that emit green, and a plurality of pixels that emit blue. The active matrix display device is characterized in that a thin film transistor for driving is provided for each emission color.   The active matrix display device according to claim 1, wherein the monitor element and the light-emitting element are EL elements.   9. The active matrix display device according to claim 1, wherein the monitor element and the light-emitting element are formed in the same process using the same material. 10. An EL television in which the display device according to claim 1 is incorporated.

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