Light-emitting device

Abstract

To provide an active matrix type display device with a simple circuit structure, in which a threshold can be corrected.SOLUTION: In a circuit illustrated in FIG. 1, pulses are input to a first gate signal line 101 and a second gate signal line 102 in accordance with a timing chart in FIG. 3, so that a transistor in the circuit is turned on or off. As a result, the potential difference between a third node N3 and a second node N2 is determined just by a potential VData of a data line 103 and a potential V2 of a second wire 105 regardless of a threshold of a fourth transistor 112. Thus, an intended current can be supplied to a display element 107.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an active matrix display device. In particular, the present invention relates to a display device having a diode characteristic. The present invention relates to an active matrix display device using a display element having a diode characteristic. The elements are, for example, organic electroluminescent (EL) diodes and light-emitting diodes. These include, but are not limited to, diode characteristics or It exhibits characteristics similar to those of a diode, and as a result, the amount of light emitted, the transmittance, the reflectance, the color tone, and the saturation The term "display element" refers to an element in which the optical characteristics change due to changes such as the above. Hereinafter, the term "display element" will also be used simply. [Background technology]

[0002] A typical example of an electro-optical element having diode characteristics is an organic EL element. The electroluminescent elements are formed in a matrix on a substrate, and each element is controlled by a transistor to display an image. Active matrix organic electroluminescence (EL) display devices that display the above light are known.

[0003] The transistors used in active matrix organic EL displays have a limited temperature range. Because of the need to form large areas in the area, amorphous silicon, polysilicon, and oxide A compound semiconductor or the like is used (see, for example, Patent Documents 1 to 3).

[0004] Transistors using such semiconductor materials generally have a large variation in threshold voltage. In an EL display device, the degree of light emission is controlled by the current value flowing through the organic EL element, and gradation is obtained. In an active matrix organic EL display device, the current flowing through the organic EL element is controlled by a transistor. The current is controlled by a transistor, but the current value also depends on the transistor threshold value. When the threshold value of the driving transistor varies, the current value flowing through the organic EL element also varies, resulting in uneven display. This occurs.

[0005] In order to suppress display defects caused by such variations in the threshold value, a technique of correcting the threshold value using a plurality of transistors is known (see Patent Document 2 and Patent Document 3). Patent Document 2 and Patent Document 3 show examples of configuring a threshold correction circuit using only N-channel transistors, only P-channel transistors, or a combination of N-channel transistors and P-channel transistors. Patent Document 2 and Patent Document 3 show examples of configuring a threshold correction circuit using only N-channel transistors, only P-channel transistors, or a combination of N-channel transistors and P-channel transistors. This occurs. This occurs.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] By the way, depending on the available semiconductor material, there are cases where a practical P-channel transistor cannot be obtained. Conversely, there are also cases where an N-channel transistor cannot be obtained. Also, due to the manufacturing method and structural problems of the display element, it may be required that the transistor be connected to the positive electrode of the display element. Conversely, it may be required that the transistor be connected to the negative electrode of the display element. This occurs. This occurs. This occurs. This occurs.

[0008] For example, only N-channel transistors can be used, and the transistor is connected to the positive electrode of the display element. When it is required to be connected to the positive electrode, the method described in Patent Document 2 cannot be adopted. In such a case, for example, it was necessary to use a circuit as described in FIG. 39 of Patent Document 3.

[0009] The circuit disclosed in Patent Document 3 is shown in FIG. 2. FIG. 2 shows the circuit required for one dot (the minimum unit constituting the display device, and usually one pixel is composed of a plurality of types of primary color dots). It is. In addition to the nine wirings of the first gate signal line 201, the second gate signal line 202, the third gate signal line 203, the fourth gate signal line 204, the fifth gate signal line 205, the data line 206, the first wiring 207, the second wiring 208, and the third wiring 209 (which are formed on the element), a light emitting element 210, a capacitor 211, a first transistor 212, a second transistor 2 13, a third transistor 214, a fourth transistor 215, a fifth transistor 216, a dot using seven transistors, namely, a sixth transistor 217 and a seventh transistor 218.

[0010] Needless to say, an increase in the number of wirings and elements is not preferable because it reduces the manufacturing yield. One aspect of the present invention has an object of proposing a more simplified circuit configuration. Further, one aspect of the present invention has an object of proposing a driving method for the above circuit.

[0011] Note that the description of these problems does not prevent the existence of other problems. Note that one aspect of the present invention does not need to solve all of these problems. Note that other problems will become apparent from the descriptions in the specification, drawings, claims, etc., and the specification, drawings, claims From descriptions such as these, it is possible to extract problems other than these.

Means for Solving the Problems

[0012] The configuration capable of solving the above problems is shown below. Prior to that, the terms used in this specification will be described. In this specification and the like, a transistor is an element having at least three terminals including a gate, a drain, and a source. And, there is a channel region between the drain (drain terminal, drain region or drain electrode) and the source (source terminal, source region or source electrode), and current can flow through the drain, the channel region, and the source.

[0013] Here, since the source and the drain change depending on the structure or operating conditions of the transistor, etc., it is difficult to limit which one is the source or the drain. Therefore, the part that functions as the source, and the part that functions as the drain are not called the source or the drain respectively. In some cases, one of the source and the drain is denoted as the first electrode, and the other of the source and the drain is denoted as the second electrode.

[0014] Regarding two-terminal elements such as capacitors and diodes, in some cases, one electrode is called the first electrode and the other electrode is called the second electrode. At that time, in the case of capacitors and diodes, even when there is a distinction between the positive electrode and the negative electrode, it does not indicate which one the first electrode is. However, when it is necessary to specify the positive electrode and the negative electrode due to the nature of the circuit, it may be described separately.

[0015] In this specification and the like, terms such as first, second, and third refer to various elements, members, regions, Layers and regions are used to describe them separately from others. Thus, the first, second, third, etc. None of these terms limit the number of elements, members, regions, layers, areas, etc. Further, for example it is possible to replace "first" with "second" or "third", etc.

[0016] In addition, when it is explicitly described in this specification, etc. that X and Y are connected, it includes the case where X and Y are electrically connected, the case where X and Y are functionally connected, and the case where X and Y are directly connected. Here, X and Y are assumed to be objects (for example devices, elements, circuits, wirings, electrodes, terminals, conductive films, layers, etc.). Therefore it is not limited to a predetermined connection relationship, for example, the connection relationship shown in the figure or the text, but includes those other than the connection relationship shown in the figure or the text.

[0017] As an example of the case where X and Y are electrically connected, an element (for example, a switch, a transistor, a capacitor element, an inductor, a resistor element, a diode etc.) that enables the electrical connection between X and Y can be connected with one or more between X and Y.

[0018] In addition, when it is explicitly described that X and Y are electrically connected, it includes the case where X and Y are electrically connected (that is, connected with another element or another circuit sandwiched between X and Y) and the case where X and Y are functionally connected (that is, functionally connected with another circuit sandwiched between X and Y), and the case where X and Y are directly connected ( that is, connected without another element or another circuit sandwiched between X and Y). That is, when it is explicitly described as being electrically connected, it simply means connection​ It is to be considered the same as the case where it is only explicitly described as being so.

[0019] In the present specification and the like, for all terminals of active elements (such as transistors), passive elements (such as capacitors), etc., even if the connection destination thereof is not specified, those skilled in the art may be able to constitute an aspect of the invention. In particular, when there are multiple cases where the connection destination of the terminal is conceivable, it is not necessary to limit the connection destination of the terminal to a specific location. Therefore it may be possible to constitute an aspect of the invention by specifying the connection destination only for some terminals of active elements, passive elements, etc.

[0020] In the present specification and the like, for a certain circuit, if at least the connection destination is specified, those skilled in the art

[0021] may be able to specify the invention. Or, for a certain circuit, if at least the function is specified, those skilled in the art may be able to specify the invention.

[0022] Therefore, for a certain circuit, even if the function is not specified, if the connection destination is specified, it is disclosed as an aspect of the invention and it is possible to constitute an aspect of the invention. Also for a certain circuit, even if the connection destination is not specified, if the function is specified, it is disclosed as an aspect of the invention and it is possible to constitute an aspect of the invention. ​​​​​​​​Moreover, it is not limited to this, and it may also be singular.

[0023] In addition, in this specification and the like, pixels may be arranged (arrayed) in a matrix. Here, when pixels are arranged (arrayed) in a matrix, it means that in the vertical or horizontal direction, if the pixels are arranged in a straight line, or if they are arranged on a jagged line, it shall be included. Therefore, for example, when performing full-color display with three color elements (e.g., RGB), if it is arranged in stripes, when the dots of the three color elements are arranged in a delta pattern, when it is arranged in a Bayer pattern, when it is arranged in a mosaic pattern, etc. shall also be included. Note that the size of the display area may be different for each dot of the color element. By this, power consumption can be reduced, or the lifespan of the display element can be extended.

[0024] One aspect of the present invention has a first gate signal line, a second gate signal line, a data line, a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a capacitor, and a display element. The gate of the first transistor is connected to the first gate signal line, the first electrode of the first transistor is connected to the data line, and the second electrode of the first transistor is connected to the second electrode of the fourth transistor and the first electrode of the fifth transistor. The gate of the second transistor is connected to the first gate signal line, the first electrode of the second transistor is connected to the second electrode of the third transistor and the first electrode of the fourth transistor. The second electrode of the second transistor is connected to the gate of the fourth transistor and the first electrode of the capacitor. The gate of the third transistor is connected to the second gate signal line, and the second electrode of the fourth transistor is connected to the fifth transistor. ​is connected to the first electrode of the switch, the gate of the fifth transistor is connected to the second gate signal line, and the fifth electrode of the transistor is connected to the first electrode of the display element, the second electrode of the capacitor, and the first electrode of the sixth transistor. The gate of the sixth transistor is connected to the first gate signal line, and it has a circuit, which is an active matrix type display device.

[0025] Note that the number of transistors is not limited to six, and there may be seven or more. Also, neither the capacitor nor the display element is limited to one, and any of them may have two or more, and both may have two or more. Note that those in which the capacitor and the display element are structurally formed in series or parallel are regarded as one capacitor and one display element.

[0026] Here, all of the first transistor to the sixth transistor are of the same conductivity type. If the first transistor to the sixth transistor are N-channel type, the first electrode of the display element is the positive electrode and the second electrode is the negative electrode. Also, if the first transistor to the sixth transistor are P-channel type , the first electrode of the display element is the negative electrode and the second electrode is the positive electrode.

[0027] Also, if the first transistor to the sixth transistor are N-channel type, the potential of the first electrode of the third transistor is higher than the potential of the second electrode of the sixth transistor and the potential of the second electrode of the display element. If the first transistor to the sixth transistor are P-channel type, the potential of the first electrode of the third transistor is lower than the potential of the second electrode of the sixth transistor and the potential of the second electrode of the display element.

[0028] Note that when the first transistor to the sixth transistor are N-channel type, the sixth transistor The potential of the second electrode of the first transistor may be lower than or equal to the potential of the negative electrode of the display element. Also, the potential of the second electrode of the sixth transistor may be higher than the potential of the negative electrode of the display element. However, it is preferable that the potential difference between the second electrode of the first transistor and the negative electrode of the display element is smaller than the threshold value of the display element. Preferably.

[0029] Furthermore, the absolute value of the difference between the potential of the first electrode of the third transistor and the potential of the second electrode of the display element is preferably 5 times or more the absolute value of the threshold value of the fourth transistor.

[0030] Also, in one aspect of the present invention, in the above circuit, the pulse input to the second gate signal line has a period overlapping with the pulse input to the first gate signal line. This is a driving method of an active matrix type display device. matrix type display device. Preferably.

[0031] Also, one aspect of the present invention includes a display element, a capacitor, a data line, a first gate signal line, a second gate signal line, a plurality of transistors (transistor A) whose gates are connected to the first gate signal line, a plurality of transistors (transistor B) whose gates are connected to the second gate signal line, a transistor (transistor C) having a first electrode of one of the transistor A and a second electrode of one of the transistor B connected to its first electrode, a gate of one of the second electrodes of the transistor A and the first electrode of the capacitor connected thereto, and a second electrode of the other of the transistor B and a second electrode of the other of the transistor A connected to its second electrode. This is an active matrix type display device having a circuit. Here, the other first electrode of the transistor A may be connected to the data line. Also, the transistor Preferably. matrix type display device. type display device.

[0032] Here, the other first electrode of the transistor A may be connected to the data line. Also, the transistor The other second electrode of B may be connected to the first electrode of the display element. Also, all of transistors A to transistor C may be of the N-channel type. Further, the potential of the first electrode of transistor C may be higher than the potential of the second electrode of the display element.

[0033] Also, in one aspect of the present invention, in the above circuit, a first period in which both transistors A and B are on, a second period in which transistor A is on and transistor B is off, a third period in which both transistors A and B are off, and a fourth period in which transistor A is off and transistor B is on are provided. A driving method of an active matrix type display device characterized by having. Here, it is preferable that the second period follows the first period, the third period follows the second period, the fourth period follows the third period, and the first period follows the fourth period. Also, the first period and the third period may be set to be equal. Here, it is preferable that the second period follows the first period, the third period follows the second period, the fourth period follows the third period, and the first period follows the fourth period. Also, the first period and the third period may be set to be equal. Here, it is preferable that the second period follows the first period, the third period follows the second period, the fourth period follows the third period, and the first period follows the fourth period. Also, the first period and the third period may be set to be equal. Here, it is preferable that the second period follows the first period, the third period follows the second period, the fourth period follows the third period, and the first period follows the fourth period. Also, the first period and the third period may be set to be equal.

[0034] Here, it is preferable that the second period follows the first period, the third period follows the second period, the fourth period follows the third period, and the first period follows the fourth period. Also, the first period and the third period may be set to be equal. Here, it is preferable that the second period follows the first period, the third period follows the second period, the fourth period follows the third period, and the first period follows the fourth period. Also, the first period and the third period may be set to be equal. Here, it is preferable that the second period follows the first period, the third period follows the second period, the fourth period follows the third period, and the first period follows the fourth period. Also, the first period and the third period may be set to be equal.

Effects of the Invention

[0035] With the above configuration, the number of wirings and the number of elements (number of transistors) required for a pixel (or dot) can be reduced. For example, compared with the example of FIG. 2, three gate signal lines are reduced to two. Since a pulse needs to be input to the gate signal line, a driving circuit for that is also required, but when the number of gate signal lines decreases, the driving circuit for that becomes unnecessary, and accordingly, power consumption can be reduced. Also, when the number of wirings decreases, it is suitable for increasing the integration degree. With the above configuration, the number of wirings and the number of elements (number of transistors) required for a pixel (or dot) can be reduced. For example, compared with the example of FIG. 2, three gate signal lines are reduced to two. Since a pulse needs to be input to the gate signal line, a driving circuit for that is also required, but when the number of gate signal lines decreases, the driving circuit for that becomes unnecessary, and accordingly, power consumption can be reduced. Also, when the number of wirings decreases, it is suitable for increasing the integration degree. With the above configuration, the number of wirings and the number of elements (number of transistors) required for a pixel (or dot) can be reduced. For example, compared with the example of FIG. 2, three gate signal lines are reduced to two. Since a pulse needs to be input to the gate signal line, a driving circuit for that is also required, but when the number of gate signal lines decreases, the driving circuit for that becomes unnecessary, and accordingly, power consumption can be reduced. Also, when the number of wirings decreases, it is suitable for increasing the integration degree. With the above configuration, the number of wirings and the number of elements (number of transistors) required for a pixel (or dot) can be reduced. For example, compared with the example of FIG. 2, three gate signal lines are reduced to two. Since a pulse needs to be input to the gate signal line, a driving circuit for that is also required, but when the number of gate signal lines decreases, the driving circuit for that becomes unnecessary, and accordingly, power consumption can be reduced. Also, when the number of wirings decreases, it is suitable for increasing the integration degree. With the above configuration, the number of wirings and the number of elements (number of transistors) required for a pixel (or dot) can be reduced. For example, compared with the example of FIG. 2, three gate signal lines are reduced to two. Since a pulse needs to be input to the gate signal line, a driving circuit for that is also required, but when the number of gate signal lines decreases, the driving circuit for that becomes unnecessary, and accordingly, power consumption can be reduced. Also, when the number of wirings decreases, it is suitable for increasing the integration degree.

[0036] Particularly, for wirings that require potential fluctuations other than the data lines (that is, connected to the gates of transistors) The number of subsequent wirings is five in FIG. 2, but in the present invention, it can be two. Since potential fluctuations lead to an increase in power consumption, power consumption can be reduced by reducing the wirings that require potential fluctuations.

[0037] Even with such a simplified configuration, it is possible to correct the threshold voltage variations of transistors equivalently to the conventional example. Further, in a display element (for example, an organic EL element or a light emitting diode) in which display characteristics deteriorate over time with use, it is also possible to compensate for such deterioration.

[0038]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

BEST MODE FOR CARRYING OUT THE INVENTION

[0039] Hereinafter, embodiments will be described with reference to the drawings. However, the embodiments can be implemented in many different modes, and without departing from the spirit and scope thereof, the forms and It will be readily understood by those skilled in the art that various changes in details can be made. Therefore, the present invention is not construed as being limited to the description of the following embodiments. It is not construed as being limited to the description of the following embodiments.

[0040] In addition, in the drawings, the size, layer thickness, or area may be exaggerated for clarity. Therefore, it is not necessarily limited to that scale.

[0041] Note that the drawings schematically show ideal examples and are not limited to the shapes or values shown in the drawings. For example, it can include variations in shape due to manufacturing techniques, variations in shape due to errors, variations in signals, voltages, or currents due to noise, or variations in signals, voltages, or currents due to timing deviations. For example, variations in shape due to manufacturing techniques, variations in shape due to errors, variations in signals, voltages, or currents due to noise, or variations in signals, voltages, or currents due to timing deviations. Furthermore, the technical terms are often used for the purpose of describing specific embodiments or examples. However, one aspect of the invention is not construed as being limited by the technical terms. Furthermore, the technical terms are often used for the purpose of describing specific embodiments or examples. However, one aspect of the invention is not construed as being limited by the technical terms.

[0042] Furthermore, the technical terms are often used for the purpose of describing specific embodiments or examples. However, one aspect of the invention is not construed as being limited by the technical terms. However, one aspect of the invention is not construed as being limited by the technical terms. .

[0043] In addition, words not defined in this specification (including scientific and technical words such as technical terms or academic terms) can be used as having the same meaning as the general meaning understood by ordinary skilled persons. Words defined by a dictionary or the like are preferably interpreted in a meaning that does not conflict with the background of the related art. In addition, words not defined in this specification (including scientific and technical words such as technical terms or academic terms) can be used as having the same meaning as the general meaning understood by ordinary skilled persons. Words defined by a dictionary or the like are preferably interpreted in a meaning that does not conflict with the background of the related art. In addition, words not defined in this specification (including scientific and technical words such as technical terms or academic terms) can be used as having the same meaning as the general meaning understood by ordinary skilled persons. Words defined by a dictionary or the like are preferably interpreted in a meaning that does not conflict with the background of the related art. In addition, words not defined in this specification (including scientific and technical words such as technical terms or academic terms) can be used as having the same meaning as the general meaning understood by ordinary skilled persons. Words defined by a dictionary or the like are preferably interpreted in a meaning that does not conflict with the background of the related art.

[0044] Note that the content described in one embodiment (even part of the content) can be applied, combined, or replaced with the content described in another part of that embodiment (even part of the content), and / or the content described in one or more other embodiments (even part of the content). Note that the content described in one embodiment (even part of the content) can be applied, combined, or replaced with the content described in another part of that embodiment (even part of the content), and / or the content described in one or more other embodiments (even part of the content). Note that the content described in one embodiment (even part of the content) can be applied, combined, or replaced with the content described in another part of that embodiment (even part of the content), and / or the content described in one or more other embodiments (even part of the content). Note that the content described in one embodiment (even part of the content) can be applied, combined, or replaced with the content described in another part of that embodiment (even part of the content), and / or the content described in one or more other embodiments (even part of the content).

[0045] In the case of referring to those of the same material or those formed simultaneously, the same reference numerals may be used However, especially when it is necessary to distinguish among them, " _1", " _ 2", etc. may be appended to the reference numerals for display. For example, when a plurality of first layer wirings 303 are formed of the same material in the drawing, reference numerals such as "303_1", "303_2", etc. are assigned to each of them. And when the first layer wiring is collectively referred to in the specification, it is denoted as "first layer wiring 303" but when one of them is to be distinguished from the others, it may be denoted as "first layer wiring 303_1" in this way.

[0046] (Embodiment 1) FIG. 1(A) illustrates an example of a circuit of a display device according to this embodiment. The circuit shown in FIG. 1(A) is used as one dot of the display device. It has six wirings: a first gate signal line 101, a second gate signal line 102, a data line 103, a first wiring 104, a second wiring 105, and a third wiring 106. The potentials of the first wiring 104, the second wiring 105, and the third wiring 106 may each be kept constant. Among these, the second wiring 105 and the third wiring 106 may be designed and set to have the same potential.

[0047] Further, it has a display element 107, a capacitor 108, a first transistor 109, a second transistor 110, a third transistor 111, a fourth transistor 112, a fifth transistor 113, and a sixth transistor 114.

[0048] The gate of the first transistor 109 is connected to the first gate signal line 101, and the first transistor The first electrode of the 109 is connected to the data line 103, and the second electrode of the first transistor 109 is connected to the second electrode of the fourth transistor 112 and the first electrode of the fifth transistor 113.

[0049] Also, the gate of the second transistor 110 is connected to the first gate signal line 101, and the first electrode of the second transistor 110 is connected to the second electrode of the third transistor 111 and the first electrode of the fourth transistor 11 2, and the second electrode of the second transistor 110 is connected to the gate of the fourth transistor 112 and the first electrode of the capacitor 108.

[0050] The gate of the third transistor 111 is connected to the second gate signal line 102, the second electrode of the fourth transistor 112 is connected to the first electrode of the fifth transistor 113, the gate of the fifth transistor 11 3 is connected to the second gate signal line 102, and the second electrode of the fifth transistor 113 is the table connected to the first electrode of the display element 107, the second electrode of the capacitor 108, and the first electrode of the sixth transistor 114. The gate of the sixth transistor 114 is connected to the first gate signal line 101.

[0051] Furthermore, the first electrode of the third transistor 111 is connected to the first wiring 104, the second electrode of the sixth transistor 114 is connected to the second wiring 105, and the second electrode of the display element 107 is connected to the third wiring 1 06. The first wiring 104, the second wiring 105, and the third wiring 106 may be set to maintain a constant potential.

[0052] Note that the intersection of the second electrode of the first transistor 109, the second electrode of the fourth transistor 112, and the first electrode of the fifth transistor 113 is the first node N1, and the second electrode of the fifth transistor 113 The intersection of the pole, the first electrode of the sixth transistor 114, and the first electrode of the display element 107 is defined as the second node N2. The intersection of the second electrode of the second transistor 110, the gate of the fourth transistor 112, and the first electrode of the capacitor 108 is called the third node N3.

[0053] Here, all the transistors are of the N-channel type. Therefore, the first electrode of the display element 107 is the positive electrode, and the second electrode is the negative electrode. Also, the potential of the first wiring 104 is required to be higher than the potentials of the second wiring 1 05 and the third wiring 106. The potential difference is set considering the breakdown voltage of the circuit, etc. However, the larger the potential difference, the more the threshold voltage dispersion of the transistor and the deterioration of the display element can be compensated for the reasons described later.

[0054] The potential difference is also determined by the display performance of the display element 107. For example, if the threshold voltage of the fourth transistor 112 is set to +1V, the potential difference between the first wiring 104 and the third wiring 106 should be 5V or more, preferably 10V or more. Hereinafter, the potential of the first wiring 104 is denoted as V1 , the potential of the second wiring 105 is denoted as V2, and the potential of the third wiring 106 is denoted as V3. For example, the potential V1 can be +10V, the potential V2 can be 0V, and the potential V3 can be 0V.

[0055] To drive the circuit shown in Fig. 1(A), video data is input to the data line 103, and , pulse signals as shown in Fig. 3 are input to the first gate signal line 101 and the second gate signal line 102. Here, V H is the potential at which the above transistor turns on, and V L is the potential at which it turns off.

[0056] As shown in Fig. 3, one frame is the potential of the first gate signal line 101 and the second gate signal ​​​The potential of line 102 is both V H during period a, and the potential of the first gate signal line 101 is V H while the potential of the second gate signal line 102 is V L during period b, and the potential of the first gate signal line 101 and the second gate signal line 102 are both V L during period c, and the potential of the first gate signal line 101 is V L while the potential of the second gate signal line 102 is V H during period d. It consists of these four periods

[0057] Note that the period τ1 during which the potential of the first gate signal line 101 is V H and the period τ2 during which the potential of the second gate signal line 102 is V may be different, but it is preferable to design them to be the same because the circuit L can be simplified. That is, after shaping one pulse, the pulse can be output to the first gate signal line 101 as it is. On the other hand, by outputting the inverted version of the same pulse through a delay circuit, it can be output to the second gate signal line 102 Below, using FIG. 4, the operating states of the transistors in each period will be described. In FIG. 4(A) shows the state of the transistors in period a, FIG. 4(B) shows the state in period b, FIG. 4(C) shows the state in period c, and FIG. 4(D) shows the state in period

[0058] d. For transistors in the on state, a circle is superimposed on the transistor symbol, and for transistors in the off state, an × is superimposed for notation In period a, all the transistors (the first transistor 109, the second transistor 110, the third transistor 111, the fifth transistor 113, the sixth transistor 114) connected to the first gate signal line 101 and the second gate signal line 102 turn on. Also, the fourth transistor is marked with a circle for transistors in the on state and an × for transistors in the off state

[0059] In period a, all the transistors (the first transistor 109, the second transistor 110, the third transistor 111, the fifth transistor 113, the sixth transistor 114) connected to the first gate signal line 101 and the second gate signal line 102 turn on. Also, the fourth transistor the fifth transistor 113, the sixth transistor 114) connected to the first gate signal line 101 and the second gate signal line 102 turn on. Also, the fourth transistor In stage 112, the potential of the gate and the potential of the first electrode are approximately equal to V1, and the potential of the second electrode (the first node N1) is approximately equal to the potential V of the data line 103 Data , but the latter is sufficiently smaller than the former so it turns on. At this time, the potential of the first electrode (the third node N3 ) of the capacitor is approximately equal to V1, and the potential of the second electrode (the second node N2) of the capacitor is approximately equal to V2 .

[0060] As described above, a potential difference occurs between the first electrode and the second electrode of the fourth transistor 112 in the on state, and a potential difference also occurs between the first electrode and the second electrode of the fifth transistor 113 in the on state . Therefore, the fourth transistor 112 and the fifth transistor 113 consume power. For this reason, period a is preferably as short as possible, and it is preferably set to 100 ns to 500 ns .

[0061] In period b, since the potential of the second gate signal line 102 becomes V L , the third transistor 111 and the fifth transistor 113 connected thereto turn off. The potential of the third node N3 is the same as the potential in period a at the beginning of period b. On the other hand, the first transistor 109, the second transistor 110, and the sixth transistor 114 are on. Therefore, the potential of the first node N1 is , the potential V of the data . Also, the potential of the second node N2 becomes V2. Data

[0062] The fourth transistor 112 is on, and since the potential V Data is lower than the potential V1, charge flows from the third node N3 through the first electrode of the fourth transistor 112 to the first node N1 . Along with this, the potential of the third node N3 decreases. Along with the flow of this charge, the third The potential drop of node N3 continues until the potential of the third node N3 becomes (V Data +V th ). That is, the potential difference between the first electrode and the second electrode of the capacitor 108 is (V +V Data +V th −V2).

[0063] During period c, since the potential of the first gate signal line 101 also becomes V L , the first transistor 109, the second transistor 110, and the sixth transistor 114 connected thereto also turn off. Here , the potentials of the first node N1, the second node N2, and the third node N3 hardly change compared to those in period b. change.

[0064] During period d, since the potential of the second gate signal line 102 becomes V H , the third transistor 111 and the fifth transistor 113 connected thereto turn on. At the beginning of period d, since the potential of the second node N2 is V2, when the fifth transistor 113 turns on, the potential of the second electrode of the fourth transistor 112 also becomes V2. Also, when the third transistor 111 turns on, the potential of the first electrode of the fourth transistor 112 becomes V1.

[0065] At this time, the potential of the gate of the fourth transistor 112 is (V Data +V th +V), and the potential of the first electrode is higher than that of the second electrode. Therefore, the potential difference (V +V Data +V th −V2) between the gate and the second electrode of the fourth transistor 112 is smaller than the potential difference (V1−V2) between the first electrode and the second electrode, and the current I flowing between the first electrode and the second electrode follows the formula for the drain current in the saturation region. ​

[0066] That is, it is proportional to the square of the value obtained by subtracting the threshold value from the potential difference between the gate and the source (in this case, the second electrode). In this case, the second electrode of the fourth transistor 112 corresponds to the source.

[0067] I ∝ {(V Data + V th ― V2) ― V th} 2 = (V Data ― V2) 2 (Equation 1 )

[0068] As is clear from Equation 1, the current I does not depend on the threshold value of the fourth transistor 112.

[0069] As current flows and charge accumulates at the second node, the potential of the second node N2 rises. However, the increase in the potential of the second node N2 causes an increase in the potential of the third node N3 due to capacitive coupling through the capacitor 108. Therefore, the difference between the potential of the third node N3 and the potential of the second node N2 remains unchanged. That is, regardless of the potential of the second node N2, the current I is constant. However, the increase in the potential of the second node N2 causes an increase in the potential of the third node N3 due to capacitive coupling through the capacitor 108. Therefore, the difference between the potential of the third node N3 and the potential of the second node N2 remains unchanged. That is, regardless of the potential of the second node N2, the current I is constant. As the potential of the second node N2 increases, the display element 107 becomes more likely to conduct current. When the potential of the second node N2 reaches a certain value, the current flowing through the display element 107 and the current I reach equilibrium. That is, the potential of the second node N2 becomes constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V As is clear from Equation 1, the potential of the second node N2 remains constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V

[0070] As the potential of the second node N2 increases, the display element 107 becomes more likely to conduct current. When the potential of the second node N2 reaches a certain value, the current flowing through the display element 107 and the current I reach equilibrium. That is, the potential of the second node N2 becomes constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V As the potential of the second node N2 increases, the display element 107 becomes more likely to conduct current. When the potential of the second node N2 reaches a certain value, the current flowing through the display element 107 and the current I reach equilibrium. That is, the potential of the second node N2 becomes constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V and so on. That is, the potential of the second node N2 becomes constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V and so on. That is, the potential of the second node N2 becomes constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V As is clear from Equation 1, the potential of the second node N2 remains constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V Data and so on. That is, the potential of the second node N2 becomes constant. The display element 107 changes its display state (such as light emission amount, transmittance, reflectance, color tone, chroma, etc.) according to the value of the current flowing through it, but that state is determined by the potential of the data V In this way, variations in the threshold values of the transistors can be corrected.

[0071] As is clear from Equation 1, for the current I to be constant, it is essential that the potential of the third node N3 be constant. If the potential of the third node N3 fluctuates, the current I will also fluctuate accordingly. For example, if the off characteristics of the second transistor 110 are insufficient, the potential of the third node N3 will rise during the period of one frame.

[0072] As the potential of the third node N3 rises, the current I also increases. Such fluctuations appear as defects in individual pixels or dots, but can also be observed throughout the display device . In excessive cases, display defects such as flickering will occur. Therefore, in particular, it is preferable that the off characteristics of the second transistor 11 0 be sufficient (that is, the off current be sufficiently low).

[0073] (Embodiment 2) In this embodiment, one aspect of the display device of the present invention will be described with reference to FIGS. 5 to 7. In this embodiment, a display device using an organic EL as a light-emitting element will be described. In particular , a top emission type display device in which a light-emitting layer is formed on an active matrix circuit and light is irradiated above the active matrix circuit for display will be described.

[0074] FIGS. 5(A) to 5(C) show the layout of wirings, contact holes, semiconductor layers, etc. used for fabricating one dot of the display device. Note that various insulating films, etc. are not shown. The rectangle indicated by the dotted line in each figure represents one dot.

[0075] FIG. 5(A) shows the positions of the first layer wiring 303, the semiconductor layer 305, and the first contact hole 306 from the first layer wiring to the upper wiring. Among these, the first layer wiring 303_1 is shown in FIG. 1(A It is a wiring corresponding to the second wiring 105 in It becomes a part of the first gate signal line 101 in FIG. 1(A). Also, the first-layer wiring 303_4 becomes a part of the second gate signal line 102 in FIG. 1(A). Also, a part of the first-layer wiring 303_3 becomes a part of the first electrode of the capacitor 108 in FIG. 1(A). The other first-layer wirings 303 become the gates of the first transistor 109 to the sixth transistor 114 in FIG. 1(A).

[0076] Also, the semiconductor layers 305_1, 305_2, 305_3, 305 _4, 305_5, 305_6 respectively become the semiconductor layers of the first transistor 109, the second transistor 110, the third transistor 111, the fourth transistor 1 12, the fifth transistor 113, and the sixth transistor 114 in FIG. 1(A).

[0077] FIG. 5(B) shows the position of the second-layer wiring 307 and the second contact hole 31 0 connecting to the wiring above it. Among these, the second-layer wiring 307_1 becomes the data line 103 in FIG. 1(A) . Also, a part of the second-layer wiring 307_6 becomes a part of the second electrode of the capacitor 108 in FIG. 1(A) . The other second-layer wirings 307 become the first electrode or the second electrode of the first transistor 109 to the sixth transistor 114 in FIG. 1(A).

[0078] FIG. 5(C) shows the position of the third-layer wiring 311 and the third contact hole 3 14 connecting to the first electrode of the display element. Among these, the third-layer wiring 311_1 becomes a part of the first gate signal line 1 01 in FIG. 1(A), the third-layer wiring 311_4 becomes a part of the second gate signal line 102, and the third layer wiring 311_5 becomes a part of the first wiring 104.

[0079] Stack a wiring layer, a semiconductor layer, contact holes, etc. having the shapes shown in FIGS. 5(A) to 5(C). By doing so, a circuit used for a display device can be fabricated. Hereinafter, with reference to FIGS. 6 and 7, an explanation of the fabrication method of the display device will be given. FIGS. 6 and 7 are cross-sectional views of the fabrication process, but correspond to the cross-section of the dashed line A - B in FIGS. 5(A) to 5(C).

[0080] Form a base insulating layer 302 on a first substrate 301 having an insulating surface. Further, after forming a conductive layer, perform a first photolithography process to form a resist mask, and remove unnecessary portions by etching to form a first-layer wiring 303. As shown in FIG. 6(A), when etching is performed so that a tapered shape is formed at the end of the first-layer wiring 303, it is preferable because the covering property of the laminated film is improved.

[0081] There is no major limitation on the substrate that can be used for the first substrate 301, but at least it is necessary to have heat resistance to withstand subsequent heat treatment. A glass substrate can be used for the first substrate 301, but it is not limited to this, and various transparent, opaque, insulating, and conductive materials can be used. In particular, in this embodiment, since the light used for display is irradiated above the first substrate, the substrate does not need to be transparent. For example, a metal material may be used to enhance heat dissipation.

[0082] When using a glass substrate as the first substrate, when the temperature of the subsequent heat treatment is high, it is preferable to use one having a strain point of 730°C or higher. Further, for the glass substrate, for example, glass materials such as aluminosilicate glass, aluminoborosilicate glass, and barium borosilicate glass are used. ​​​​​​​​​​​​It is used. By including more barium oxide (BaO) compared to boric acid, a more practical heat-resistant glass can be obtained. Therefore, it is preferable to use a glass substrate containing more BaO than B2O3.

[0083] Instead of the above glass substrate, a substrate made of an insulator such as a ceramic substrate, a quartz substrate, or a sapphire substrate

[0084] The underlying insulating layer 302 has a function of preventing the diffusion of impurity elements from the first substrate 301, and also has a function of maintaining the insulation of the circuit when the first substrate 301 is conductive. The underlying insulating layer 302

[0085] can be formed by a laminated structure of one or more films selected from a silicon nitride film, a silicon oxide film, a silicon oxynitride film, or a silicon nitride oxide film. For example, a structure in which indium nitride or molybdenum oxide with a high work function is laminated on Ti can be used.

[0086] Next, a gate insulator 304 is formed on the first layer wiring 303. The gate insulator 304 can be formed by a single layer or a laminate of a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, a silicon nitride oxide layer, or an aluminum oxide layer using

[0087] Next, a semiconductor layer is formed, and island-shaped semiconductor layer 305 is formed by a second photolithography process. The material of semiconductor layer 305 can be formed using a silicon semiconductor or an oxide semiconductor. Examples of silicon semiconductors include single-crystalline silicon and polycrystalline silicon, and examples of oxide semiconductors include In-Ga-Zn-based oxides, which can be appropriately used.

[0088] Here, for example, the In-Ga-Zn-based oxide means an oxide mainly composed of In, Ga, and Zn, and the ratio of In, Ga, and Zn is not limited. Also, other metal elements may be included in addition to In, Ga, and Zn.

[0089] For example, as semiconductor layer 305, an oxide semiconductor that is an In-Ga-Zn-based oxide is used to form a semiconductor layer with low off-current, thereby reducing the leakage current of the transistor. In particular, keeping the potential of the third node N3 in FIG. 1(A) constant is preferable for improving the display quality.

[0090] Note that the oxide semiconductor is not limited to the In-Ga-Zn-based oxide, and those containing at least indium ( In) or zinc (Zn) may be used. In particular, it is preferable to contain In and Zn. Also, in order to reduce the variation in the electrical characteristics of the transistor using the oxide semiconductor, it is preferable to have gallium (Ga) in addition to them as a stabilizer. Further, it is preferable to have tin (Sn) as a stabilizer. Also, it is preferable to have hafnium (Hf) as a stabilizer. Also, it is preferable to have aluminum (Al) as a stabilizer.

[0091] Also, as other stabilizers, lanthanum (La), cerium, which are lanthanoids, (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), hol mium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lut etium (Lu) may have any one or more of them.

[0092] For example, as other oxide semiconductors, indium oxide, tin oxide, zinc oxide, binary metal oxides such as In-Zn system oxides, Sn-Ga-Zn system oxides, Al-Ga-Zn system oxides, Sn-Al-Zn system oxides, Sn-Zn system oxides, Al-Zn system oxides, Zn- Mg system oxides, Sn-Mg system oxides, In-Mg system oxides, In-Ga system oxides, ternary metal oxides such as In-Al-Zn system oxides, In-Sn-Zn system oxides, In-Hf -Zn system oxides, In-La-Zn system oxides, In-Ce-Zn system oxides, In-Pr- Zn system oxides, In-Nd-Zn system oxides, In-Sm-Zn system oxides, In-Sm-Z n system oxides, In-Eu-Zn system oxides, In-Gd-Zn system oxides, In-Tb-Zn system oxides, In-Dy-Zn system oxides, In-Ho-Zn system oxides, In-Er-Zn system oxides, In-Tm-Zn system oxides, In-Yb-Zn system oxides, In-Lu-Zn system acid oxides, quaternary metal oxides such as In-Sn-Ga-Zn system oxides, In-Hf-Ga- Zn system oxides, In-Al-Ga-Zn system oxides, In-Sn-Al-Zn system oxides, I n-Sn-Hf-Zn system oxides, In-Hf-Al-Zn system oxides can be used. .

[0093] For example, oxides of an In-Ga-Zn system with an atomic ratio of In:Ga:Zn = 1:1:1 (= 1 / 3:1 / 3:1 / 3) or In:Ga:Zn = 2:2:1 (= 2 / 5:2 / 5:1 / 5), and oxides in the vicinity of their compositions can be used. Alternatively, oxides of an In-Sn-Zn system with an atomic ratio of In:Sn:Zn = 1:1:1 (= 1 / 3:1 / 3:1 / 3), In:Sn:Zn = 2:1:3 (= 1 / 3:1 / 6:1 / 2), or In:Sn:Zn = 2:1:5 (= 1 / 4:1 / 8:5 / 8), and oxides in the vicinity of their compositions may be used. However, it is not limited to these, and those with an appropriate composition may be used according to the required semiconductor characteristics (mobility, threshold value, variation, etc.). Also, in order to obtain the required semiconductor characteristics, it is preferable to make the carrier concentration, impurity concentration, defect density, atomic number ratio of metal element and oxygen, interatomic bond distance, density, etc. appropriate. For example, in an In-Sn-Zn system oxide, relatively high mobility can be obtained easily. However, even in an In-Ga-Zn system oxide, the mobility can be increased by increasing the defect density in the bulk. Note that, for example, an oxide with an atomic ratio of In:Ga:Zn = a:b:c (a + b + c = 1) is in the vicinity of an oxide with an atomic ratio of In:Ga:Zn = A:B:C (A + B + C = 1) by r means that a, b, and c satisfy (a - A) 2 +(b - B) 2 +(c - C) 2 ≤ r 2 . As r, for example, 0.05 may be used. The same applies to other oxides.

[0094]

[0095]

[0096] (a―A) 2 +(b―B) 2 +(c―C) 2 ≦r 2 ​

[0097] The oxide semiconductor may be single crystal or non-single crystal. In the latter case, it may be amorphous or polycrystalline and may also have a structure including a crystalline portion in the amorphous. It may also be non-amorphous .

[0098] Since an amorphous oxide semiconductor can relatively easily obtain a flat surface, interface scattering when manufacturing a transistor using this can be reduced, and relatively easily, relatively high mobility can be obtained.

[0099] Also, in a crystalline oxide semiconductor, more bulk defects can be reduced, and if the flatness of the surface is enhanced, mobility higher than that of an amorphous oxide semiconductor can be obtained. To enhance the flatness of the surface, it is preferable to form the oxide semiconductor on a flat surface , specifically, it may be formed on a surface with an average surface roughness (Ra) of 1 nm or less, preferably 0.3 nm or less, more preferably 0.1 nm or less.

[0100] After forming the semiconductor layer 305, a first contact hole 306 reaching the first layer wiring is formed in a part of the gate insulator 304 by a third photolithography process. The method for forming the first contact hole 306 may be appropriately selected such as dry etching or wet etching . The cross section up to here is shown in FIG. 6(A).

[0101] Next, a conductive film is formed on the gate insulator 304 and the semiconductor layer 305, and a second layer wiring 307 is formed by a fourth photolithography graphy process. As the conductive film used for the second layer wiring 307 , for example, a metal film containing an element selected from Al, Cr, Cu, Ta, Ti, Mo, and W , or a metal nitride film containing the above-described elements as components (such as a titanium nitride film, a molybdenum nitride film, a tungsten nitride film), etc. can be used.

[0102] Also, on one or both of the lower side and the upper side of a metal film such as Al or Cu, a high melting point metal film such as Ti, Mo, or W or a metal nitride film thereof (titanium nitride film, molybdenum nitride film, tungsten nitride film) may be laminated.

[0103] Also, the second layer wiring 307 may be formed of a conductive metal oxide. As the conductive metal oxide, indium oxide, tin oxide, zinc oxide, In - Sn - based oxide (such as ITO), In - Zn - based oxide, or those containing silicon oxide in these metal oxide materials can be used.

[0104] Next, a first interlayer insulator 308 and a second interlayer insulator 309 are formed on the semiconductor layer 305 and the second layer wiring 307. As the first interlayer insulator 308, an inorganic insulating film such as a silicon oxide film or a silicon oxynitride film can be used. As the second interlayer insulator 309, it is preferable to select an insulating film having a planarizing function in order to reduce surface irregularities caused by transistors. For example, inorganic materials such as SOG (spin - on glass), and organic materials such as polyimide, acrylic, benzocyclobutene, etc. can be used. The second interlayer insulator 309 may be formed by laminating a plurality of insulating films formed of these materials.

[0105] Next, by a fifth photolithography process, a second contact hole 310 reaching the second layer wiring 307 is formed in the first interlayer insulator 308 and the second interlayer insulator 309. The second contact ​​​​​​​​​​​The method for forming the tact hole 310 may be appropriately selected, such as dry etching or wet etching. The state up to this point is shown in FIG. 6(B). That's all. The state up to this point is shown in FIG. 6(B).

[0106] Next, a conductive film is formed on the second interlayer insulator, and the third layer wiring 311 is formed by the sixth photolithography process. As the conductive film used for the third layer wiring 311, it can be selected from the materials used for the second layer wiring 307, but those with particularly low resistivity are preferred, and Cu or its alloy may be used. That's all.

[0107] Next, a third interlayer insulator 312 and a fourth interlayer insulator 313 are formed on the third layer wiring 311. The third interlayer insulator 312 and the fourth interlayer insulator 313 can be formed of materials that can be used for the first interlayer insulator 308 and the second interlayer insulator 309.

[0108] Next, by the seventh photolithography process, a third contact hole 314 reaching the third layer wiring 311 is formed in the third interlayer insulator 312 and the fourth interlayer insulator 313. The method for forming the third contact hole 314 may be appropriately selected such as dry etching or wet etching. The state up to this point is shown in FIG. 6(C). That's all. The state up to this point is shown in FIG. 6(C).

[0109] Next, a conductive film is formed on the fourth interlayer insulator 313, and by the eighth photolithography process a reflective electrode layer 315 is formed. The reflective electrode layer 315 corresponds to the first electrode of the display element 107 in FIG. 1(A). As the reflective electrode layer 315, in order to improve the light extraction efficiency, a material that efficiently reflects the light emitted by the light-emitting layer 317 formed later is preferred.

[0110] Note that the reflective electrode layer 315 may have a laminated structure. For example, gold is on the side in contact with the light-emitting layer 317 A conductive film made of an oxide, or a thin film of titanium or the like is formed, and on the other hand, a metal film with high reflectivity (such as aluminum, an alloy containing aluminum, or silver) can be used. By configuring it in this way, it is possible to suppress the formation of an insulating film formed between the light-emitting layer 317 and the metal film with high reflectivity (such as aluminum, an alloy containing aluminum, or silver), so it is preferable. Next, a partition wall 316 is formed on the reflective electrode layer 315. As the partition wall 316, an organic insulating material or an inorganic insulating material is used. In particular, it is preferable to use a photosensitive resin material to form an opening on the reflective electrode layer 315 so that the side wall of the opening becomes an inclined surface formed with a continuous curvature. Next, a light-emitting layer 317 is formed on the reflective electrode layer 315 and the partition wall 316, and a transmissive electrode layer 318 is formed on the light-emitting layer 317. The light-emitting layer 317 may be composed of a single layer or a plurality of layers laminated, but in this embodiment, the light emitted by the light-emitting layer 317 is white, and it is preferable to have light having peaks in the respective wavelength regions of red, green, and blue. In this embodiment, since an organic EL material is used as the light-emitting layer 317, the light-emitting layer 317 is preferably formed by a vacuum deposition method. Also, due to its characteristics, it is difficult to pattern the film formed on the light-emitting layer 317 and above by a photolithography process, so the light-emitting layer 317 and the transmissive electrode layer 318 are uniformly formed on the first substrate. Note that the transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A). It is suitable.

[0111] Next, a partition wall 316 is formed on the reflective electrode layer 315. The partition wall 316 is formed using an organic insulating material or an inorganic insulating material. In particular, a photosensitive resin material is used to form an opening on the reflective electrode layer 315 such that the side wall of the opening becomes an inclined surface formed with a continuous curvature. It is preferably formed in this way. Next, a light-emitting layer 317 is formed on the reflective electrode layer 315 and the partition wall 316, and a transmissive electrode layer 318 is formed on the light-emitting layer 317. The light-emitting layer 317 may be composed of a single layer or a plurality of layers laminated, but in this embodiment, the light emitted by the light-emitting layer 317 is white, and it is preferable to have light having peaks in the respective wavelength regions of red, green, and blue. It is preferably formed in this way.

[0112] Next, a light-emitting layer 317 is formed on the reflective electrode layer 315 and the partition wall 316, and a transmissive electrode layer 318 is formed on the light-emitting layer 317. The light-emitting layer 317 may be composed of a single layer or a plurality of layers laminated, but in this embodiment, the light emitted by the light-emitting layer 317 is white, and it is preferable to have light having peaks in the respective wavelength regions of red, green, and blue. The light-emitting layer 317 may be composed of a single layer or a plurality of layers laminated, but in this embodiment, the light emitted by the light-emitting layer 317 is white, and it is preferable to have light having peaks in the respective wavelength regions of red, green, and blue. In this embodiment, since an organic EL material is used as the light-emitting layer 317, the light-emitting layer 317 is preferably formed by a vacuum deposition method. Also, due to its characteristics, it is difficult to pattern the film formed on the light-emitting layer 317 and above by a photolithography process, so the light-emitting layer 317 and the transmissive electrode layer 318 are uniformly formed on the first substrate. Note that the transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A). In this embodiment, since an organic EL material is used as the light-emitting layer 317, the light-emitting layer 317 is preferably formed by a vacuum deposition method. Also, due to its characteristics, it is difficult to pattern the film formed on the light-emitting layer 317 and above by a photolithography process, so the light-emitting layer 317 and the transmissive electrode layer 318 are uniformly formed on the first substrate. Note that the transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A).

[0113] In this embodiment, since an organic EL material is used as the light-emitting layer 317, the light-emitting layer 317 is preferably formed by a vacuum deposition method. Also, due to its characteristics, it is difficult to pattern the film formed on the light-emitting layer 317 and above by a photolithography process, so the light-emitting layer 317 and the transmissive electrode layer 318 are uniformly formed on the first substrate. Note that the transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A). In this embodiment, since an organic EL material is used as the light-emitting layer 317, the light-emitting layer 317 is preferably formed by a vacuum deposition method. Also, due to its characteristics, it is difficult to pattern the film formed on the light-emitting layer 317 and above by a photolithography process, so the light-emitting layer 317 and the transmissive electrode layer 318 are uniformly formed on the first substrate. Note that the transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A). In this embodiment, since an organic EL material is used as the light-emitting layer 317, the light-emitting layer 317 is preferably formed by a vacuum deposition method. Also, due to its characteristics, it is difficult to pattern the film formed on the light-emitting layer 317 and above by a photolithography process, so the light-emitting layer 317 and the transmissive electrode layer 318 are uniformly formed on the first substrate. Note that the transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A). In this embodiment, since an organic EL material is used as the light-emitting layer 317, the light-emitting layer 317 is preferably formed by a vacuum deposition method. Also, due to its characteristics, it is difficult to pattern the film formed on the light-emitting layer 317 and above by a photolithography process, so the light-emitting layer 317 and the transmissive electrode layer 318 are uniformly formed on the first substrate. Note that the transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A). The transmissive electrode layer 318 corresponds to the second electrode of the display element 107 in FIG. 1(A).

[0114] By the above process, a transistor for controlling the driving of the light-emitting element and the light-emitting layer 317 are formed. The state up to this point is shown in FIG. 7(A).

[0115] Next, a method for manufacturing the second substrate 319 on which the light-shielding film 320, the color filter 321, and the overcoat film 322 are formed will be shown below. The second substrate 319 needs to be transparent, but other conditions are looser compared to the first substrate 301, and a material with inferior heat resistance can also be used. However, other conditions are looser compared to the first substrate 301, and a material with inferior heat resistance can also be used.

[0116] First, an opaque film is formed on the second substrate 319, and a photolithography process is performed to form the light-shielding film 320. The light-shielding film 320 can prevent color mixing and light leakage between pixels. Note that the light-shielding film 320 may not be provided. As the light-shielding film 320, a metal film with a low reflectivity such as titanium or chromium, or an organic resin film impregnated with a black pigment or a black dye can be used. By the light-shielding film 320, color mixing and light leakage between pixels can be prevented. Note that the light-shielding film 320 may not be provided. As the light-shielding film 320, a metal film with a low reflectivity such as titanium or chromium, or an organic resin film impregnated with a black pigment or a black dye can be used. Note that the light-shielding film 320 may not be provided. As the light-shielding film 320, a metal film with a low reflectivity such as titanium or chromium, or an organic resin film impregnated with a black pigment or a black dye can be used.

[0117] Next, a color filter 321 is formed on the second substrate 319 and the light-shielding film 320. The color filter 321 is a colored layer that transmits light in a specific wavelength band. For example, a red (R) color filter that transmits light in the red wavelength band, a green (G) color filter that transmits light in the green wavelength band, or a blue (B) color filter that transmits light in the blue wavelength band can be used. Each color filter can be formed at a desired position using a known material by a printing method, an inkjet method, an etching method using photolithography technology, or the like. The color filter 321 is a colored layer that transmits light in a specific wavelength band. For example, a red (R) color filter that transmits light in the red wavelength band, a green (G) color filter that transmits light in the green wavelength band, or a blue (B) color filter that transmits light in the blue wavelength band can be used. Each color filter can be formed at a desired position using a known material by a printing method, an inkjet method, an etching method using photolithography technology, or the like. Each color filter can be formed at a desired position using a known material by a printing method, an inkjet method, an etching method using photolithography technology, or the like.

[0118] Here, a method using three colors of RGB has been described, but it is not limited to this, and R ​​​​​It may be a configuration using four colors, GB and Y (yellow), or a configuration using five or more colors.

[0119] Next, an overcoat film 322 is formed on the light-shielding film 320 and the color filter 321. The overcoat film 322 is preferably made of an organic resin film such as acrylic or polyimide. The overcoat film 322 can remove impurities contained in the color filter 321. It is possible to prevent the components from diffusing to the light-emitting layer 317 side. The insulating film 2 may have a laminated structure of an organic resin film and an inorganic insulating film. The overcoat film 322 may be formed of silicon, silicon oxide, or the like. It is not necessary to do so.

[0120] Through the above steps, the light-shielding film 320, the color filter 321, and the overcoat film 322 are formed. Then, the first substrate 301 and the second substrate 319 are formed. The two are aligned and bonded together to form a display device.

[0121] There is no particular limitation on the bonding of the first substrate 301 and the second substrate 319. The first substrate 301 and the second substrate 302 are connected to each other by a light-transmitting adhesive. A sealed space 323 is formed between the first and second electrodes 19. The space 323 is not particularly limited, and may be a light-transmitting space. It is sufficient that the insulation is stable and that outside air does not enter.

[0122] However, it is preferable to fill the space 323 with a light-transmitting material having a refractive index greater than that of air. When the refractive index is small, the light emitted from the light emitting layer 317 in an oblique direction enters the space 323. This causes further refraction, and in some cases, light may escape from adjacent pixels. As 323, for example, an adhesive with a large refractive index that allows the first substrate 301 and the second substrate 319 to be adhered can be used. Also, an adhesive with high light transmittance can be used.

[0123] In addition, an inert gas such as nitrogen or argon can also be used. Further, a desiccant or the like may be dispersed in the space 323. The state up to this point is shown in FIG. 7(B). The display device shown in FIG. 7(B) is a display device having a so-called top emission structure that emits light from the light-emitting layer 317 toward the second substrate 319. Further, it is a structure in which white light emitted from the light-emitting layer 317 is color-separated by the color filter 321.

[0124] A display device having a top emission structure (hereinafter abbreviated as a white + CF + TE structure) combining such a white light-emitting light-emitting element and a color filter, and a top emission structure of a light-emitting element formed by a painting method (hereinafter abbreviated as a painting + TE structure) are compared. The painting method is a method of painting each pixel with RGB materials by a vapor deposition method or the like. First, regarding colorization, in the case of the white + CF + TE structure, colorization is performed using a color filter. Therefore, a color filter is required. On the other hand, in the case of the painting + TE structure, since each pixel is painted by vapor deposition or the like to perform colorization, a color filter is not required. However, in the white + CF + TE structure, a color filter is required, but in the painting + TE structure, a metal mask or the like is required for painting. In addition, it is also possible to perform painting using an inkjet or the like without using a metal mask.

[0125]

[0126] ​​​​​​​​​​​​There are still many technical problems.

[0127] In addition, when using a metal mask, the vapor deposition material is also deposited on the metal mask, so there are also problems such as poor material utilization efficiency and high cost. Also, since the metal mask contacts the light-emitting element, destruction of the light-emitting element, or scratches, particles, etc. due to the contact occur, resulting in a decrease in yield.

[0128] Next, regarding the pixel size, in the case of the divided coating + TE structure, it is necessary to separately coat the colors of each pixel, and it is necessary to provide an area for separation between pixels. Therefore, the size of one pixel cannot be increased. As a result, the aperture ratio is significantly reduced. On the other hand, in the case of the white + CF + TE structure, since there is no need to provide an area for separation between pixels, the size of one pixel can be increased, and accordingly, the aperture ratio can be improved.

[0129] Also, when increasing the size of the display device, the manufacturing technology of the display device becomes an essential element. In the case of the divided coating + TE structure, a metal mask is required for coating, and the technology and production equipment for large-sized metal masks have not been established and are difficult. Also, even if the technology and production equipment for large-sized metal masks are established, the problem of material utilization efficiency such as the vapor deposition material being deposited on the metal mask is not solved. On the other hand, in the case of the white + CT + TE structure, since a metal mask is not required, it is possible to manufacture using the existing production equipment, which is suitable.

[0130] Also, regarding the productivity of the display device, the manufacturing equipment of the display device is an important element. For example, when the light-emitting element has a multi-stage stacked structure, the equipment for manufacturing the display device is It is preferable to form a plurality of vapor deposition sources as multi-chambers on a substrate at once or continuously. In the case of the divided + TE structure, since it is necessary to paint each pixel a different color, it is necessary to form it at a desired position by exchanging the metal mask. To exchange the metal mask, it is difficult to make the manufacturing apparatus inline or multi-chamber. On the other hand, in the case of the white + CF + TE structure, since there is no need to use a metal mask, it is easy to configure the manufacturing apparatus as an inline or multi-chamber type.

[0131] (Embodiment 3) In this embodiment, an example of an electronic device manufactured using the display device described in the above embodiment will be described with reference to FIG. 8.

[0132] As an example of an electronic device to which the present invention is applicable, a television device (also referred to as a television or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone, a portable game machine, a portable information terminal, an audio reproduction device, a gaming machine (such as a pachinko machine or a slot machine), and a game cabinet can be mentioned. Specific examples of these electronic devices are shown in FIG. 8.

[0133] FIG. 8(A) shows a table 400 having a display unit. The table 400 has a display unit 403 incorporated in a housing 4 01. A display device manufactured using an aspect of the present invention can be used for the display unit 403, and it is possible to display an image on the display unit 403. Note that a configuration in which the housing 401 is supported by four legs 402 is shown. Also shown is a power cord 405 for power supply in the housing 401.

[0134] The display unit 403 has a touch input function, and by touching the display button 404 displayed on the display unit 403 of the table 400 with a finger or the like, screen operations and information can be input. Also, the screen of the display unit 403 can be set perpendicular to the floor by a hinge provided on the housing 401, and it can also be used as a television device. In a narrow room, installing a television device with a large screen will narrow the free space, but if the table has a built-in display unit, the space in the room can be effectively utilized. If the display device provided with the light-shielding spacer shown in the previous embodiment is used, color bleeding, color shift, etc. are less likely to occur in the display, so by using the display device for the display unit 403, a display unit 403 with higher display quality than before can be obtained. Also, since a pair of substrates are held by the light-shielding spacer, it is extremely resistant to external forces such as impact and distortion, so it can be suitably used as the table shown in Fig. 8(A). Fig. 8(B) shows a television device 410. The television device 410 has a display unit 412 incorporated in a housing 411. The display device manufactured using one aspect of the present invention can be used for the display unit 412, and the display unit 412 can display an image. Here, a configuration in which the housing 411 is supported by a stand 413 is shown. The operation of the television device 410 can be performed by an operation switch provided on the housing 411 or a separate remote control operation unit 414. The operation keys 41 provided on the remote control operation unit 414

[0135]

[0136]

[0137] By 6, operations such as channel and volume can be performed, and the image displayed on the display unit 412 can be operated. Also, a configuration may be adopted in which the remote control operation unit 414 is provided with a display unit 415 for displaying information output from the remote control operation unit 414. The television device 410 shown in FIG. 8(B) includes a receiver, a modem, and the like. The television device 410 can receive general television broadcasts by a receiver, and further

[0138] by connecting to a wired or wireless communication network via a modem, one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication can also be performed. (sender to receiver) or two-way (sender and receiver, or receivers among themselves, etc.) information communication can also be performed.

[0139] If the display device provided with the light-shielding spacer shown in the previous embodiment is used, bleeding and color shift in the display are less likely to occur. Therefore, by using the display device for the display unit 412 of the television device, a television device with higher display quality than conventional ones can be obtained. bleeding, color shift, etc. in the display are less likely to occur. Therefore, by using the display device for the display unit 412 of the television device, a television device with higher display quality than conventional ones can be obtained. bleeding, color shift, etc. in the display are less likely to occur. Therefore, by using the display device for the display unit 412 of the television device, a television device with higher display quality than conventional ones can be obtained. can be achieved.

[0140] FIG. 8(C) shows a personal computer 420, which includes a housing 421, a housing 422, a display unit 4 23, a keyboard 424, an external connection port 425, a pointing device 426, etc. The computer is manufactured by using the display device manufactured according to one aspect of the present invention for its display unit 423. The computer is manufactured by using the display device manufactured according to one aspect of the present invention for its display unit 423.

[0141] Also, if the display device provided with the light-shielding spacer shown in the previous embodiment is used, bleeding and color shift in the display are less likely to occur. Therefore, by using the display device for the By using it for the display unit 423, it becomes possible to obtain a display unit with higher display quality than conventional ones. It can be achieved.

[0142] Fig. 8(D) shows an example of a mobile phone. The mobile phone 430 includes, in addition to a display unit 432 incorporated in a housing 431, a power button 433, an external connection port 434, a speaker 435 , a microphone 436, operation buttons 437, etc. The mobile phone 430 is manufactured by using a display device manufactured using an aspect of the present invention for the display unit 432.

[0143] The mobile phone 430 shown in Fig. 8(D) can perform operations such as inputting information, making a call, or creating an email by touching the display unit 432 with a finger or the like.

[0144] The screen of the display unit 432 mainly has three modes. The first is a display mode mainly for displaying images, and the second is an input mode mainly for inputting information such as characters. The third is a mode in which the two modes of the display mode and the input mode are mixed.

[0145] For example, when making a call or creating an email, the display unit 432 can be set to an input mode mainly for inputting characters, and an input operation of the characters displayed on the screen can be performed. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display unit 432.

[0146] Also, by providing a detection device having sensors such as a gyro and an acceleration sensor inside the mobile phone 430 to detect the inclination, the orientation (portrait or landscape) of the mobile phone 430 can be determined, and the screen display of the display unit 432 can be automatically switched.

[0147] In addition, the switching of the screen mode is performed by touching the display unit 432 or operating the operation buttons 437 of the housing 431. Also, it is possible to switch according to the type of image displayed on the display unit 432. For example, if the image signal to be displayed on the display unit is video data then switch to the display mode, and if it is text data, switch to the input mode.

[0148] Also, in the input mode, the signal detected by the optical sensor of the display unit 432 is detected, and if there is no input by the touch operation of the display unit 432 for a certain period, the screen mode may be controlled to switch from the input mode to the display mode.

[0149] Also, the display unit 432 can also function as an image sensor. For example, by touching the palm or finger on the display unit 432 and imaging the palm print, fingerprint, etc., personal authentication can be performed Also, if a backlight that emits near-infrared light or a light source for a sensor that emits near-infrared light is used for the display unit, it is also possible to image finger veins, palm veins, etc. Using the display device provided with the light-shielding spacers shown in the previous embodiment, since color bleeding, color shift, etc. are less likely to occur in the display, by using the display device for the display unit 4

[0150] 32 of the mobile phone, it is possible to make a mobile phone with higher display quality than before. Also, since a pair of substrates are held by the light-shielding spacers, it is extremely resistant to any external force such as impact and distortion, and can be suitably used as the mobile phone shown in Fig. 8(D). In addition, since a pair of substrates are held by the light-shielding spacers, it is extremely resistant to any external force such as impact and distortion, and can be suitably used as the mobile phone shown in Fig. 8(D).

[0151] As described above, the configurations, methods, etc. shown in the present embodiment are suitable for the configurations, methods, etc. shown in other embodiments. ​​​They can be used in combination.

Explanation of symbols

[0152] 101 First gate signal line 102 Second gate signal line 103 Data line 104 First wiring 105 Second wiring 106 Third wiring 107 Display element 108 Capacitor 109 First transistor 110 Second transistor 111 Third transistor 112 Fourth transistor 113 Fifth transistor 114 Sixth transistor 201 First gate signal line 202 Second gate signal line 203 Third gate signal line 204 Fourth gate signal line 205 Fifth gate signal line 206 Data line 207 First wiring 208 Second wiring 209 Third wiring 210 Light-emitting element 211 Capacitor 212 First transistor 213 Second transistor 214 Third transistor 215 Fourth transistor 216 Fifth transistor 217 Sixth transistor 218 Seventh transistor 301 First substrate 302 Underlying insulating layer 303 First layer wiring 304 Gate insulator 305 Semiconductor layer 306 First contact hole 307 Second layer wiring 308 First interlayer insulator 309 Second interlayer insulator 310 Second contact hole 311 Third layer wiring 312 Third interlayer insulator 313 Fourth interlayer insulator 314 Third contact hole 315 Reflective electrode layer 316 Partition wall 317 Light-emitting layer 318 Transparent electrode layer 319 Second substrate 320 Light-shielding film 321 Color filter 322 Overcoat film 323 Space 400 Table 401 Housing 402 Leg 403 Display unit 404 Display button 405 Power cord 410 Television device 411 Housing 412 Display unit 413 Stand 414 Remote control operation unit 415 Display unit 416 Operation key 420 Personal computer 421 Housing 422 Housing 423 Display unit 424 Keyboard 425 External connection port 426 Pointing device 430 Mobile phone 431 Housing 432 Display unit 433 Power button 434 External connection port 435 Speaker 436 Microphone 437 Operation button N1 First node N2 Second node N3 Third Node

Claims

1. a first wiring to which video data is supplied; a first gate signal line intersecting the first wiring; a second gate signal line intersecting the first wiring; a second wiring intersecting the first wiring; a light-emitting element; a first transistor having a function of controlling a current flowing from the second wiring to the light-emitting element in accordance with the video data, in a pixel; a first conductive film having a function as the second wiring, a second conductive film having a function as the first gate signal line, and a third conductive film having a function as the second gate signal line each have a region in contact with an upper surface of a first insulating film; a fourth conductive film having a function as a gate electrode of the first transistor has a region in contact with an upper surface of a second insulating film different from the first insulating film, and does not overlap with the second conductive film and the third conductive film in a plan view; a fifth conductive film having a function as the first wiring has a region in contact with an upper surface of a third insulating film different from the first insulating film; a light-emitting device.

2. In Claim 1, the second wiring, the first gate signal line, and the second gate signal line have a region extending along the same direction; a light-emitting device.

3. In Claim 1 or Claim 2, a second transistor is provided in the pixel; the first gate signal line is electrically connected to a gate electrode of the second transistor; a sixth conductive film having a function as a gate electrode of the second transistor has a region in contact with an upper surface of the second insulating film; a light-emitting device.

4. In any one of Claims 1 to 3, a third transistor is provided in the pixel; the second gate signal line is electrically connected to a gate electrode of the third transistor; a seventh conductive film having a function as a gate electrode of the third transistor has a region in contact with an upper surface of the second insulating film; a light-emitting device.

Images