JP2006208538A - Electrooptical apparatus, electronic device, and manufacturing method of electrooptical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of an electrooptical apparatus by which a capacitance ratio can be secured even if a pixel area is reduced. <P>SOLUTION: In the electrooptical apparatus having a pair of substrates, an electrooptical substance 130 interposed between the pair of substrates, pixel electrodes 114 disposed on one side of the electrooptical substance, two terminal type nonlinear elements 117 connected to the pixel electrodes, a counter electrode 122 opposed to the pixel electrodes via the electrooptical substance, a driving IC driving the electrooptical substance and wirings 118 disposed outside a display region of the substrate and connecting the driving IC to the counter electrode, a capacitance electrode 112 disposed in opposition to the electrooptical substance with respect to the pixel electrodes and constructing auxiliary capacitance between the pixel electrodes and the auxiliary electrode is provided, the counter electrode is conductively connected to the wirings 118 provided on the pixel electrode side of the electrooptical substance and the capacitance electrode is conductively connected to the wirings. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electro-optical device, an electronic apparatus, and an electro-optical device manufacturing method, and more particularly to a structure of an electro-optical device suitable as various display devices having a switching element and a pixel electrode connected to the switching element.

  In general, an electro-optical device including a switching element such as a thin film transistor (TFT) or a thin film diode (TFD), for example, an active matrix liquid crystal device is known. In such an electro-optical device, a switching element is interposed between the image signal line and the pixel electrode, and an image signal is supplied from the image signal line to the pixel electrode via the switching element, thereby opposing the pixel electrode. A predetermined electric field is formed between the counter electrode (common electrode) and the optical state of the electro-optical material (liquid crystal).

  By the way, the predetermined voltage applied between the pixel electrode and the counter electrode based on the image signal supplied through the switching element is held for a certain period by turning off the switching element. For example, in the case of a liquid crystal device, In this period, the optical state of the liquid crystal is maintained. However, when the element capacitance of the switching element is increased, there is a problem that the display state is deteriorated because the voltage varies due to the variation of the wiring potential. That is, by increasing the ratio between the liquid crystal capacitance and the element capacitance (hereinafter simply referred to as “capacitance ratio”), it is necessary to suppress the voltage fluctuation and improve the display quality.

  Therefore, conventionally, a method has been employed in which an auxiliary capacitance is formed in parallel with the liquid crystal capacitance, thereby increasing the total of the liquid crystal capacitance and the auxiliary capacitance with respect to the element capacitance, thereby substantially increasing the capacitance ratio. Yes. For example, when a TFT is used as a switching element, in general, an auxiliary capacitor is formed by providing a capacitor wiring facing the semiconductor layer of the TFT via a gate insulating film, and the capacitance ratio is increased by the auxiliary capacitor. There is known a method for improving display quality (for example, see Patent Documents 1 and 2 below).

On the other hand, in a liquid crystal device, a cell structure is used in which a pair of transparent insulating substrates are bonded together and a liquid crystal is arranged between the substrates. In this case, on one substrate provided with switching elements and pixel electrodes, the other A lead wire for supplying a predetermined potential to the counter electrode provided on the substrate is formed, and the lead wire is connected to the counter electrode via a conductive material disposed between one substrate and the other substrate. There are cases where conductive connection is made (see, for example, Patent Document 2 below).
Japanese Patent Laid-Open No. 2002-229061 Japanese Patent Laid-Open No. 10-282515

  However, in recent years, there has been a strong demand for an improvement in display resolution of a display unit of a portable electronic device and an improvement in display quality of a moving image. Accordingly, in order to improve the definition and response speed of an electro-optical device. In addition, a reduction in pixel area and a reduction in liquid crystal capacity are becoming unavoidable. For this reason, there is a problem that the above-mentioned capacity ratio becomes small and the display quality deteriorates.

  In this case, it is conceivable to secure the capacitance ratio by providing the auxiliary capacitance as described above. However, in this method, since it is necessary to provide the auxiliary capacitance in the formation portion of the switching element such as TFT, the light shielding area increases. In particular, when the resolution is increased, the aperture ratio of the pixel is lowered, and there is a possibility that the display contrast and brightness cannot be sufficiently secured. In addition, it is necessary to use the structure of the switching element, and it may be difficult to increase the capacitance value of the auxiliary capacitor due to restrictions on the pixel structure.

  Therefore, the present invention solves the above problems, and an object thereof is to provide a structure of an electro-optical device capable of ensuring a capacitance ratio even when the pixel area is reduced.

  In view of such circumstances, the electro-optical device of the present invention includes a pair of substrates, an electro-optical material sandwiched between the pair of substrates, a pixel electrode disposed on one side of the electro-optical material, and the pixel A two-terminal nonlinear element connected to an electrode; a counter electrode facing the pixel electrode through the electro-optic material; a drive IC for driving the electro-optic material; and the display device disposed outside the display area of the substrate. In an electro-optical device having a driving IC and a wiring for connecting the counter electrode, the auxiliary electrode is disposed opposite to the electro-optical material with respect to the pixel electrode, and an auxiliary capacitor is formed between the pixel electrode and the pixel electrode. The capacitor electrode is provided, and the capacitor electrode is conductively connected to the counter electrode. In particular, the counter electrode is conductively connected to a wiring provided closer to the pixel electrode than the electro-optical material, and the capacitor electrode is conductively connected to the lead wiring.

  According to the present invention, the capacitor electrode can be configured regardless of the two-terminal nonlinear structure by arranging the auxiliary capacitor by disposing the capacitor electrode opposite to the electro-optical material of the pixel electrode. In addition, since the auxiliary capacitor can be provided by using the pixel electrode having the existing configuration, it is only necessary to provide the capacitor electrode as a new component for providing the auxiliary capacitor, and the capacitor is provided over the entire surface of the pixel electrode. The capacitance value of the auxiliary capacitor can be easily increased without being restricted by the structure of the two-terminal nonlinear element or the pixel structure, such as allowing the electrodes to face each other. Therefore, even if high definition and high speed response are achieved, the capacity ratio can be secured, so that display quality can be prevented from deteriorating.

  More specifically, since the conventional auxiliary capacitor is constituted by a gate insulating film between the capacitor line and the TFT semiconductor layer, the TFT semiconductor layer is extended so as to be opposed to the capacitor line. In addition, since the auxiliary capacitance is formed in the element region of the TFT, there is a problem that the capacitance of the auxiliary capacitance cannot be increased. In the present invention, by making the capacitor electrode face the pixel electrode itself, the auxiliary capacitance can be increased and the aperture ratio of the pixel is hardly affected.

  In addition, since the capacitor electrode is conductively connected to the counter electrode, the voltage component applied to the capacitance component sandwiching the electro-optic material and the auxiliary capacitance is basically the same. Since the voltage applied to the electro-optical material can be accurately and reliably maintained, the effect of improving the display quality can be enhanced and stabilized.

  Further, by providing a wiring (corresponding to a routing wiring described later) on the pixel electrode side of the electro-optic material, the connection with the driving circuit is facilitated, and the capacitive electrode is conductively connected to the wiring. The conductive connection structure between the electrode and the counter electrode can be easily configured. That is, by using the wiring provided on the pixel electrode side, it is not necessary to separately provide a conductive connection structure of the capacitor electrode and the counter electrode, so that the whole can be simply configured, and therefore, it is possible to easily cope with downsizing. become.

  In the present invention, the electro-optical material includes a first substrate on which the two-terminal nonlinear element, the pixel electrode, the capacitor electrode, and the wiring are provided, and a second substrate on which the counter electrode is provided. It is preferable to arrange between the first substrate and the second substrate. An electro-optic material is disposed between the first substrate and the second substrate, a two-terminal nonlinear element, a pixel electrode, a capacitor electrode, and a wiring are provided on the first substrate, and a counter electrode is provided on the second substrate. As a result, the electro-optical device can have a general configuration and can be easily manufactured.

  In the present invention, the capacitor electrode and the wiring are preferably conductively connected via a connection wiring formed in the same layer as the pixel electrode. According to this, by electrically connecting the capacitor electrode and the wiring via a connection wiring formed in the same layer as the pixel electrode, even if other wiring or conductive structure exists in the vicinity of the wiring, Since the distance between them can be secured, the parasitic capacitance can be reduced. Further, since it is formed in the same layer as the pixel electrode, it can be formed simultaneously with the pixel electrode, and in this case, it is not necessary to increase the number of manufacturing steps. In addition, if the pixel electrode and the connection wiring are made of the same material, it is possible to prevent electrolytic corrosion from occurring between them. Note that the connection wiring is preferably provided outside the driving region in which the pixels are arranged (that is, the peripheral region).

  In the present invention, it is preferable that the capacitor electrode is formed between the pixel electrode and the two-terminal nonlinear element. According to this, by disposing the capacitor electrode on the pixel electrode side of the two-terminal nonlinear element, it is possible to reduce the distance between the pixel electrode and the capacitor electrode and increase the capacitance value of the auxiliary capacitor. The parasitic capacitance can be reduced by sufficiently securing the distance between the pixel electrode and the two-terminal nonlinear element and the wiring. As a specific structure in this case, in the first substrate, the capacitor electrode is formed on the two-terminal nonlinear element with a first interlayer insulating film interposed therebetween, and the second interlayer insulating film is formed on the capacitor electrode. The pixel electrode is formed via a contact hole, and the pixel electrode is conductively connected to the two-terminal nonlinear element through a contact hole provided in the first interlayer insulating film and the second interlayer insulating film, and is connected to the capacitor electrode. It is desirable that an opening for avoiding the contact hole is provided.

  In the present invention, it is preferable that the pixel electrode has a plurality of pixel electrodes facing the common counter electrode, and the capacitor electrode is integrally formed with a portion facing the plurality of pixel electrodes. According to this, when a common counter electrode facing a plurality of pixel electrodes is provided, the structure can be simplified by providing an integral capacitance electrode for the plurality of pixel electrodes. In addition, the facing area between the pixel electrode and the pixel electrode can be increased, and the conductive connection with the wiring is facilitated.

  In the present invention, when the pixel electrode and the capacitor electrode are made of a transparent conductor, a transmissive electro-optical device can be formed, and the pixel electrode is made of a transparent conductor. When the capacitive electrode is made of a light-reflective conductor, it is possible to construct a reflective or semi-transmissive electro-optical device in which the capacitive electrode is also used as a reflective electrode. .

  Next, an electronic apparatus according to an aspect of the invention includes the electro-optical device according to any one of the above and a control unit that controls the electro-optical device. By mounting the above-described electro-optical device in an electronic device, the display quality of a display body with high definition or high-speed response can be improved. In particular, a portable electronic device can display a high-quality image within a limited display area. Examples of the electronic device include a monitor device, a television device, a computer device, and a projection display device. Particularly, examples of the portable electronic device include a mobile phone, a portable information terminal, and an electronic timepiece.

  Furthermore, the method of manufacturing the electro-optical device according to the present invention includes a pair of substrates, an electro-optical material sandwiched between the pair of substrates, a pixel electrode disposed on one side of the electro-optical material, and the pixel electrode A two-terminal nonlinear element connected to the substrate, a counter electrode facing the pixel electrode through the electro-optic material, a drive IC for driving the electro-optic material, and the drive arranged outside the display area of the substrate In a method of manufacturing an electro-optical device having an IC for use and a wiring for connecting the counter electrode, forming the two-terminal nonlinear element and forming a first interlayer insulating film on the two-terminal nonlinear element Forming a capacitor electrode on the first interlayer insulating film; forming a second interlayer insulating film on the capacitor electrode; and forming a wiring closer to the pixel electrode than the electro-optic material. And second interlayer insulation Forming the pixel electrode conductively connected to the two-terminal nonlinear element and forming an auxiliary capacitor between the capacitor electrode and the pixel electrode; and the capacitor electrode and the wiring And a step of conductively connecting the wiring and the counter electrode. In this case, the step of forming the wiring may be performed at any stage as long as it is prior to the step of conductively connecting the capacitor electrode and the wiring. In particular, the step of forming a two-terminal nonlinear element It is desirable to do it at the same time.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Each of the attached drawings is drawn in a different manner depending on the size and abstraction necessary for explaining each part of the embodiment described below, and the actual dimensions, dimensional ratios, or shapes are accurately shown. Not shown in These dimensions and the like are appropriately pointed out in the description as necessary.

[First Embodiment]
First, the configuration of the liquid crystal display device 100 that is the electro-optical device according to the first embodiment of the invention will be described with reference to FIGS. 1 to 6. 1 is a schematic plan view showing the inner surface structure of the first substrate 110, FIG. 2 is a schematic plan view showing the inner surface structure of the second substrate 120, and FIG. 3 is a schematic longitudinal sectional view showing the overall configuration of the liquid crystal display device 100. is there.

  The liquid crystal display device 100 is formed by bonding a first substrate 110 shown in FIG. 1 and a second substrate 120 shown in FIG. 2 using a sealing material 131 as shown in FIG. In the region, the liquid crystal layer 130 is arranged inside both the substrates. The first substrate 110 and the second substrate 120 have a thickness of about 0.3 to 1.5 mm, for example, and the liquid crystal layer 130 has a thickness of about 3 to 10 μm, for example. A polarizing plate 132 is disposed on the outer surface of the first substrate 110, and a polarizing plate 133 is also disposed on the outer surface of the second substrate 120. The first substrate 110 includes a substrate extending portion 110T extending outward from the outer shape of the second substrate 120, and an X driver 134 and a Y driver 135 made of a semiconductor chip or the like are formed on the inner surface of the substrate extending portion 110T. Has been implemented.

  As shown in FIG. 3, a first interlayer insulating film 111, a capacitor electrode 112, a second interlayer insulating film 113, a pixel electrode 114, and an alignment film 115 are sequentially stacked on the inner surface of the first substrate 110. In addition, a color filter 121, a counter electrode 122, and an alignment film 123 are sequentially stacked on the inner surface of the second substrate 120.

  As shown in FIG. 1, on the inner surface of the first substrate 110, a drive region 110A in which the pixel electrodes 114 are arranged vertically and horizontally and a peripheral region 110B provided around the drive region 110A are provided. . The drive region 110A is provided with a plurality of image signal lines 116 extending in the vertical direction in the figure and a plurality of switching elements 117 respectively connected to the image signal lines 116. The switching elements 117 are respectively connected to the corresponding pixel electrodes 114. It is connected. The image signal line 116 is drawn out on the substrate overhanging portion 110T and is conductively connected to the X driver 134 described above. A plurality of routing wires 118 are provided in the peripheral region 110B, and a connection pad portion 118P is provided at one end of these routing wires 118. Further, the other end side of the lead-out wiring 118 is drawn out on the substrate extension portion 110T and is conductively connected to the Y driver 135. Further, the X driver 134 and the Y driver 135 are conductively connected to a plurality of input terminals 119 formed on the substrate extension portion 110T.

  On the other hand, as shown in FIG. 2, on the inner surface of the second substrate 120, a drive region 120A corresponding to the drive region 110A and a peripheral region 120B corresponding to the peripheral region 110B are provided. A color filter 121 is formed in the drive region 120A, and the color filter 121 is provided with colored layers 121R, 121G, and 121B that exhibit different color tones in the regions corresponding to the pixel electrodes 114. In the case of the illustrated example, the colored layers 121R, 121G, and 121B are each configured in a strip shape extending in the vertical direction in the figure, and show a color filter 121 in a striped array that is configured in a striped shape as a whole. Thus, it may be composed of other arrangement patterns.

  A plurality of strip-like counter electrodes 122 extending in the left-right direction in the figure from the drive region 120A to the peripheral regions 120B on both sides thereof are arranged in a stripe pattern. The counter electrode 122 includes a connection pad portion 122P at a position corresponding to the connection pad portion 118P of the routing wiring 118 in the peripheral region 120B. In this embodiment, a TFD element (MIM element) which is a two-terminal nonlinear element is used as the switching element.

  When the first substrate 110 and the second substrate 120 are bonded together by the sealing material 131 as shown in FIG. 3, the connection pad portions 118P and 122P are conductively connected via the sealing material 131. It is configured. In this case, the sealing material 131 contains conductive particles or the like in a base material made of insulating resin or the like, and the conductive particles are interposed between the connection pad portions 118P and 122P, thereby conducting conductive connection. A state is secured. Note that a sealing material in which conductive particles are mixed is used only in a region where the connection pad portions 118P and 122P are opposed to each other (vertical conductive portion), and conductive particles are not mixed in other regions (for example, insulating as a spacer). A sealing material in which particles are mixed may be used. Further, the connection pad portions 118P and 122P may be conductively connected not by the sealing material 131 but by a conductive material provided separately from the sealing material 131.

  4 is an enlarged plan view showing the drive region 110A of the first substrate 110 in an enlarged manner, and FIG. 5 is an enlarged view showing the switching element 117 and the surrounding structure in the pixel structure shown in FIG. It is a perspective sectional view. The image signal line 116 is conductively connected to the first pattern portion 117A constituting the switching element 117. The first pattern portion 117A is stacked on the second pattern portion 117B, and the second pattern portion 117B is the third pattern portion 117C. Are stacked. The pixel electrode 114 is conductively connected to the third pattern portion 117C. More specifically, the first interlayer insulating film 111, the capacitor electrode 112, and the second interlayer insulating film 113 are provided between the third pattern portion 117C and the pixel electrode 114 as shown in FIG. An opening 112a is formed for each pixel in the capacitor electrode 112, and the inside of the through hole formed in the first interlayer insulating film 111 and the second interlayer insulating film 113 so as to pass through the opening 112a. In addition, the constituent material of the pixel electrode 114 penetrates to form the contact portion 114a, and the pixel electrode 114 and the third pattern portion 117C are conductively connected through the contact portion 114a. Note that the capacitor electrode 112 is integrally formed across a plurality of pixels having a common counter electrode 122, and is configured in a pattern having the opening 112a for each of these pixels.

As shown in FIG. 5, the image signal line 116 includes a first metal layer 110U made of Ta or Ta alloy (Ta-W or the like), and an insulation made of Ta ₂ O ₅ or the like formed on the surface. The film 110V has a three-layer structure in which a second metal layer 110W made of Cr or the like formed on the insulating film 110V is stacked. In addition, the first pattern portion 117 </ b> A includes only the second metal layer 110 </ b> W configured integrally with the image signal line 116. The second pattern portion 117B has a structure in which the first metal layer 110U and the insulating film 110V are stacked. Further, the third pattern portion 117C is configured by the second metal layer 110W.

  The switching element 117 of the present embodiment includes an MIM (metal-insulation) of the second metal layer 110W, the insulating film 110V, and the first metal layer 110U, which is configured in the stacked portion of the first pattern portion 117A and the second pattern portion 117B. Body-metal) structure MIM structure of the first metal layer 110U, the insulating film 110V, and the second metal layer 110W, which is formed in the stacked portion of the element portion 117X having the second pattern portion 117B and the third pattern portion 117C. The element portion 117Y is formed of a structure in which the element portions 117Y are connected in series, that is, a so-called back-to-back structure, and the element portions 117X and 117Y have a symmetrical junction structure, whereby the electrical characteristics of the switching element 117 are symmetrical. (Symmetry regarding the polarity of the current-voltage characteristic) is ensured. However, the present embodiment is not limited to such a structure, and any element structure may be used as long as it has a switching function with a predetermined nonlinear characteristic.

  This embodiment shows a transflective liquid crystal device, and FIG. 4 shows a planar structure in which an optical opening 112b that defines a light transmission region is provided in the capacitor electrode 112. FIG. However, the optical aperture 112b is not necessary when a reflective liquid crystal device is configured, and the optical aperture 112b is not required when a transmissive liquid crystal device is configured by configuring the capacitive electrode 112 with a transparent conductor. There is no need to provide it.

  FIG. 6 is an enlarged partial longitudinal sectional view schematically showing a sectional structure in a range from the drive region to the peripheral region in the liquid crystal display device 100 of the present embodiment (sectional view taken along line VI-VI in FIGS. 4 and 7). FIG. 7 is an enlarged partial plan view of the first substrate in the range shown in FIG. Here, in FIGS. 6 and 7, the cross-sectional shape and planar shape of the capacitor electrode 112, the pixel electrode 114, the image signal line 116, the switching element 117, the liquid crystal layer 130, the sealing material 131, and the like are represented by schematic shapes. It is different from the actual shape. For example, the conductive particles 131a disposed in the sealing material 131 are actually substantially spherical or cylindrical, but are shown in FIG. 6 in an aspect having an elliptical cross section for convenience.

  In the present embodiment, the capacitor electrode 112 extends from the driving region to the peripheral region between the first interlayer insulating film 111 and the second interlayer insulating film 113, and in the formation region of the plurality of leading wirings 118, Conductive connection. The lead wiring 118 constitutes a connection pad portion 118P after being conductively connected to the capacitor electrode 112. A surface layer 118Q formed at the same time (with the same material) as the pixel electrode 114 is laminated on the connection pad portion 118P, and the surface layer 118Q is in conductive contact with the conductive particles 131a of the sealing material 131 constituting the vertical conduction portion. is doing.

  On the other hand, on the second substrate, there are colored layers 121R, 121G, and 121B (121B not shown) and a light-shielding portion 121M provided in the outer peripheral portion and the inter-pixel region. The color filter 121 is formed by laminating the overcoat layer 121C with a system resin or the like. The counter electrode 122 is formed on the color filter 121, and the counter electrode 122 extends from the drive region to the peripheral region to reach the connection pad portion 122P. The connection pad portion 122P has the conductive property. The particles 131a are in conductive contact.

  In the present embodiment, the pixel electrode 114 and the counter electrode 122 are made of a transparent conductor such as ITO (Indium Tin Oxide), and the capacitor electrode 112 is made of a light reflective conductor and also serves as a light reflection layer. The capacitor electrode 112 is made of an Ag alloy such as Al, Ag, or APC (Ag—Pd—Cu), or a metal material such as Cr. In particular, Al, Al alloys (alloys based on Al), Ag, Ag alloys (alloys based on Ag) have high light reflectivity, and the appearance of reflective displays is good. This is preferable. The capacitor electrode 112 is provided with the optical aperture 112b in the pixel region, and light is transmitted through the optical aperture 112b. Further, the capacitor electrode 112 is formed over the entire range overlapping the pixel electrode 114 except for the opening 112a and the optical opening 112b. In the illustrated example, the capacitor electrode 112 is also formed in an inter-pixel region where the pixel electrode 114 is not formed. .

  Note that the capacitor electrode 112 is integrally formed over a range corresponding to the formation range of the corresponding counter electrode 122 having substantially the same potential, that is, over a plurality of pixels formed by the corresponding counter electrode 122. Yes. In the case of the present embodiment, since a plurality of counter electrodes 122 are arranged in stripes, a plurality of capacitance electrodes 112 are arranged in stripes at positions corresponding to these. That is, each capacitor electrode 112 is disposed on the opposite side of each of the corresponding counter electrodes 122 with the plurality of pixel electrodes 114 interposed therebetween. Therefore, the facing area between the capacitor electrode 112 and the pixel electrode 114 can be easily increased, and the wiring structure can be easily configured as compared with the case where the capacitor electrode 112 is individually connected to a predetermined potential.

  In the present embodiment, as shown in FIG. 7, the width of the capacitor electrode 112 is formed to be substantially the same as the width of the pixel electrode 114 or slightly smaller than the width of the pixel electrode 114. Accordingly, since the width of the capacitor electrode 112 does not deviate from the range in the width direction of the pixel electrode 114, a problem in electrical configuration, for example, a short circuit between the adjacent capacitor electrodes 112 can be avoided.

  However, in order to increase the opposing area of the capacitor electrode 112 and the pixel electrode 114 to increase an auxiliary capacitance component described later, or to increase the light reflection region by the capacitor electrode 112 as much as possible, the width of the capacitor electrode 112 Is preferably the same as or larger than the width of the pixel electrode 114. In this case, in order to avoid electrical problems, it is desirable that the displacement amount in the width direction between the capacitor electrode 112 and the opposing pixel electrode 114 is 10% or less. It is more desirable to set it to 5% or less.

  In this embodiment, in order to use the capacitor electrode 112 as a light reflection layer, a fine uneven shape is formed on the surface of the first interlayer insulating film 111 by using a photolithography method or the like, and the capacitor electrode 112 is formed thereon. By forming the film, the surface of the capacitor electrode 112 is configured to function as a light-scattering reflective film. As a result, it is possible to prevent the reflection of the background and the illusion caused by the light source in the reflective display. In addition, the fine concavo-convex structure of the capacitor electrode 112 has an effect of increasing the auxiliary capacitance by increasing the electrode facing area between the capacitor electrode 112 and the pixel electrode 114.

  Furthermore, in this embodiment, since the second interlayer insulating film 113 completely covers the capacitive electrode 112, the risk of corrosion is reduced even if the capacitive electrode 112 is made of a material that is relatively easily corroded, such as Ag. can do. In addition, since the second interlayer insulating film forms a capacitive insulating film between the capacitive electrode 112 and the pixel electrode 114, it is preferable that the second interlayer insulating film has a high insulating property with little leakage current. Therefore, both the protection of the capacitor electrode 112 and the insulation of the auxiliary capacitor can be achieved at a high level. In the present embodiment, since the capacitor electrode 112 is completely covered from above and below by the first interlayer insulating film 111 and the second interlayer insulating film 113, it is possible to further enhance the corrosion resistance.

  Next, the manufacturing method of the above embodiment will be described with reference to FIGS. FIG. 9 is a schematic process diagram illustrating the entire manufacturing method of the liquid crystal display device 100 of the present embodiment, and FIG. 8 is a schematic view of the process shown in FIG. It is a detailed process figure which shows the more detailed step of the part which leads to the formation process of an electrode.

  First, schematic steps of the manufacturing method will be described with reference to FIG. In this manufacturing method, the first substrate 110 and the second substrate 120 are first formed separately. In the manufacturing process of the first substrate 110, first, in step P11, the switching element 117 is formed on the first substrate 110 together with the image signal line 116. Next, in step P12, the pixel electrode 114 is formed by a sputtering method, a photolithography method, or the like. Thereafter, the alignment film 115 is formed by screen printing or the like in step P13, and the alignment film 115 is rubbed by rubbing the surface with a roller wound with a rubbing cloth in step P14. Finally, in the process P15, the sealing material 130 is disposed on the substrate by screen printing or coating using a precision dispenser or the like.

  On the other hand, in the second substrate 120, first, the color filter 121 is formed on the substrate 120 in the process P21, and then the counter electrode 122 is formed in the process P22 by a sputtering method, a photolithography method, or the like. Further, an alignment film 123 is formed in the same manner as described above in Step P23, and a rubbing process is performed in Step P24.

  Next, in the process P31, the first substrate 110 and the second substrate 120 are bonded together via the sealing material 131 to form a front panel structure, and the sealing material is cured in the process P32. For example, if the sealing material is a thermosetting resin, it is cured by heating, and if the sealing material is a photocurable resin, it is cured by light irradiation. Here, when manufacturing a relatively small liquid crystal display device, a large-sized front panel structure including a portion corresponding to a plurality of liquid crystal display devices is formed by forming a region corresponding to a plurality of liquid crystal display devices on each substrate. Constitute. In the present embodiment, description will be made on the assumption that the front panel structure has such a multi-panel structure. Next, in the process P33, the above-mentioned front panel structure is divided by a scribe / break method or the like to expose the liquid crystal injection port where the seal material is not disposed. Thereafter, in step P34, liquid crystal is injected from the liquid crystal injection port, and in step P35, the liquid crystal injection port is sealed with a resin or the like.

  Finally, when the panel structure in which liquid crystal injection is completed includes portions corresponding to a plurality of liquid crystal display devices, the panel is further divided in step P36 to form a final panel structure (see FIG. 3). Then, a semiconductor chip such as a liquid crystal driver IC (X driver 134 and Y driver 135 shown in FIGS. 1 to 3) is mounted on the panel structure to complete the liquid crystal display device 100.

Next, more detailed contents of the manufacturing process from the above processes P11 to P12 will be described. First, in step S01 of FIG. 8, the first substrate 110 made of glass, plastic, or the like is cleaned by cleaning or the like, and the first substrate is put into a sputtering apparatus to form a base layer made of Ta ₂ O ₅ or the like. 110S (see FIG. 5) is formed. This underlayer improves the adhesion between the first substrate 110 and the image signal lines 116 and the switching elements 117 formed thereon, and prevents impurities from entering from the substrate material of the first substrate 110. belongs to. This underlayer is formed on the entire surface of the substrate.

  Next, in step S02, a Ta or Ta—W alloy film is formed to a thickness of about 150 to 1000 nm on the base layer by sputtering, and then patterning is performed by photolithography in step S03. At this time, a portion corresponding to the image signal line 116 and a portion corresponding to the second pattern portion 117B of the switching element 117 (corresponding to the first metal layer 110U) are formed at the same time. However, at this point, the pattern shape is such that the portion corresponding to the image signal line 116 and the portion corresponding to the second pattern portion 117B are connected via a connection pattern portion (not shown).

Next, in step S04, the first substrate 110 is immersed in an electrolytic solution such as citric acid, phosphoric acid, and salicylic acid, and anodization of a pattern corresponding to the image signal line 116 and the second pattern portion 117B is performed. Thereby, the surface of the pattern is oxidized, and an insulating film made of Ta ₂ O ₅ (corresponding to the insulating film 110V described above) is formed to a thickness of about 20 to 100 nm, for example. Thereafter, the surface is cleaned using a sulfuric acid solution or the like. Thereafter, in step S05, annealing (heating) is performed at 250 to 500 ° C. for about 20 to 100 minutes in order to improve the film quality and interface state of the insulating film.

  Next, in step S06, Cr or the like is deposited to a thickness of about 150 to 1000 nm by sputtering or the like to form an upper electrode layer, and patterning is performed in step S07, thereby forming the second electrode layer 110W. . Further, in step S08, the connection pattern portion is removed by photolithography, and a portion corresponding to the image signal line 116 and a portion corresponding to the second pattern portion 117B of the switching element are separated. Thereafter, in step S09, annealing is performed again in order to improve device characteristics. Thereby, the switching element 117 is completed.

  Next, in steps S10 and S11, a first interlayer insulating film 111 is formed. The first interlayer insulating film 111 is exposed by applying a photosensitive resin in step S10 and controlling the exposure degree of the photosensitive resin through an exposure mask having many fine openings by a photolithography method in step S11. By developing, a fine surface uneven structure is provided. Thereafter, in step S12, a metal such as Al is formed by sputtering or the like, and patterning is performed in step S13 to form the capacitor electrode 112. The capacitor electrode 112 also functions as a light reflection layer as described above. Here, by the patterning, an opening 112a that avoids the contact portion 114a and an optical opening 112b that defines a light transmission region are formed. When the first interlayer insulating film 111 has a fine surface uneven structure, the capacitor electrode 112 is also formed in a fine uneven shape reflecting the surface uneven structure, and has a light scattering reflective surface. It will be.

  The surface uneven shape of the capacitor electrode 112 is a range suitable for use as a light reflection layer, and the height difference of the unevenness is 0.1 to 1.0 μm, particularly 0.45 to 0.65 μm. Is preferably in the range of 1 to 20 μm, particularly 7 to 17 μm. Typically, the height difference is about 0.6 μm, and the plane distance is about 12 μm. The above range is a range desired from the request on the optical characteristics of the light-scattering reflecting surface. On the other hand, in order to increase the auxiliary capacity by increasing the facing area, the size of the surface uneven shape is not particularly limited, but the upper pixel electrode, the alignment film, etc. reflect the unevenness, and the alignment state and voltage of the liquid crystal In order to prevent the application state from becoming non-uniform, and to ensure a certain amount of increase in the facing area and its uniformity, the height difference of the unevenness is 0.1 to 1.0 μm, and the plane between the protrusions The distance is preferably in the range of 0.5 to 30 μm.

Further, in step S14, a resin material such as acrylic resin or an inorganic material such as SiO ₂ is disposed on the capacitor electrode 112, and the second interlayer insulating film 113 is formed by patterning in step S15. It is formed.

  Next, in step S16, a transparent conductor such as ITO is laminated on the second interlayer insulating film 113, and the pixel electrode 114 is formed by patterning in step S17. At the same time, the surface layer 118Q is formed of the same material on the connection pad portion 118P, thereby improving the conductive contact between the connection pad portion 118P and the conductive particles 131a in the sealing material 131. Finally, in step S18, an electrical characteristic (IV characteristic or the like) is inspected in order to confirm the electrical characteristic of the switching element 117.

  Next, the electrical configuration of the present embodiment described above will be described with reference to FIGS. In the present embodiment, as shown in FIG. 10, pixels are configured corresponding to the intersections of the image signal line 116 and the counter electrode 122 orthogonal thereto, and switching connected to the image signal line 116 in each pixel. The element 117 and the liquid crystal layer 130 disposed between the pixel electrode 114 and the counter electrode 122 are connected in series. The image signal line 116 is connected to the X driver 134, and the counter electrode 122 is connected to the Y driver 135 via the lead wiring 118.

  In the present embodiment, a second interlayer insulating film 113 is interposed between the pixel electrode 114 and the capacitor electrode 112, and the second interlayer insulating film 113 has a sufficiently large facing area between the pixel electrode 114 and the capacitor electrode 112 (that is, Therefore, it has a configuration that cannot be ignored in terms of an equivalent circuit.

FIG. 11 is a circuit diagram showing an equivalent circuit in each pixel. As shown by the solid line in this figure, the equivalent circuit of the switching element 117 is configured by a parallel circuit of a variable resistance component R _TFD and an element capacitance component C _TFD, and the variable resistance component R _TFD is a voltage applied to the switching element 117. It depends on. Specifically, when the voltage exceeds the threshold value, the variable resistance component R _TFD decreases rapidly (non-linearly), and when the voltage falls below the threshold value, the variable resistance component R _TFD increases rapidly (non-linearly). On the other hand, the liquid crystal layer 130 connected in series to the switching element 117 is composed of a parallel circuit of a resistance component R _LD and a liquid crystal capacitance component C _LD . In the present embodiment, as represented by a broken line in the drawing, the second interlayer insulating film 113 exists in parallel to the liquid crystal layer 130, which is represented by a parallel circuit of the resistance component R _Z and an auxiliary capacitance component C _Z The In the case of the present embodiment, the resistance component R _Z is sufficiently large and can be ignored in terms of a circuit. On the other hand, the auxiliary capacitance component C _Z has a considerably large value because the opposing area is large as described above. It cannot be ignored in terms of circuit.

FIG. 12 is a schematic circuit diagram showing the equivalent circuit in the pixel shown in FIG. 11 in a simplified manner and also showing the electrical connection structure of the capacitor electrode 112. Here, since the resistance component R _LD of the liquid crystal 130 and the resistance component R _Z of the second interlayer insulating film 113 shown in FIG. 11 can be ignored, they are omitted in FIG. In the case of the present embodiment, since the liquid crystal capacitance component C _LD and the auxiliary capacitance component C _Z are connected in parallel to the switching element 117, the capacitance ratio of the present embodiment is (C _LD + C _Z ) / C _TFD . , by increasing the auxiliary capacitance component C _Z, it is understood that it is possible to increase the capacitance ratio. Here, the capacitor electrode 112 is conductively connected to the counter electrode 122 via the vertical conduction portion (conductive particles 131a) and the lead wiring 118, whereby the pixel potential supplied to the pixel electrode 114 and the counter electrode are 122 and the common potential (scanning potential) supplied to the capacitor electrode 112. That is, in the present embodiment, substantially the same voltage is always applied to the liquid crystal capacitance component C _LD and the auxiliary capacitance component C _Z.

Since the auxiliary capacitance component _CZ is constituted by the capacitance electrode 112 disposed so as to be directly opposed to the pixel electrode 114, the opposed area can be increased to a value substantially equal to or exceeding the pixel area. In addition, since the voltage between both ends is substantially equal to the voltage applied to the liquid crystal layer 130, it can greatly contribute to the increase in the capacitance ratio. In particular, since the capacitor electrode 112 is formed in a fine uneven shape, the substantial opposing area of the capacitor electrode 112 and the pixel electrode 114 can be made larger than the pixel area, thereby further increasing the auxiliary capacitor component CZ. Increase can be achieved.

Further, in the present embodiment, since the configuration by the auxiliary capacitance component C _Z capacitor electrode 112 which is opposed to the pixel electrode 114, it is possible to present to the pixel electrodes 114 themselves components from already conventional, Since it is not necessary to provide any plane space only for configuring the auxiliary capacity, it is not necessary to increase the plane size, and a high-definition device can be easily configured. In particular, since the capacitor electrode 112 can be integrated (common) over a plurality of pixels arranged along the counter electrode 122 corresponding thereto, the structure can be further simplified. Further, by electrically connecting the capacitor electrode 112 to the routing wiring 118 on the first substrate 110, the conductive connection structure does not require a space, and the structure is not complicated.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described with reference to FIGS. In this embodiment, as in the first embodiment, the first substrate 110, the first interlayer insulating film 111, the capacitor electrode 112, the second interlayer insulating film 113, the pixel electrode 114, the alignment film 115, the image signal line 116, Switching element 117, routing wiring 118, second substrate 120, color filter 121, counter electrode 122, alignment film 123, liquid crystal layer 130, sealing material 131, conductive particles 131a, connection pad portions 118P and 122P, surface layer 118Q, contact Since the portion 114a, the opening 112a, and the optical opening 112b are provided, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the present embodiment, the difference from the first embodiment is that the capacitor electrode 112 is not directly conductively connected to the lead-out wiring 118, and instead, the capacitor electrode 112 is formed in the same layer as the pixel electrode 114. The point is that the conductive wiring 118 is conductively connected through the wiring portion 114 ′. The connection wiring 114 ′ is formed on the second interlayer insulating film 113 and made of the same material as the pixel electrode 114. In the manufacturing process of the present embodiment, the connection wiring 114 ′ is formed in the same process as the pixel electrode 114 and is simultaneously formed by patterning the pixel electrode 114. Specifically, in the connection wiring 114 ′, the contact portion 114 a ′ is conductively connected to the capacitor electrode 112 through a through hole formed in the second interlayer insulating film 113, and the first interlayer insulating film 111 and the second interlayer insulating film 114 ′. The contact portion 114 b ′ is conductively connected to the lead wiring 118 through a through hole formed in the insulating film 113.

  With the configuration as described above, in the first embodiment, the distance between the capacitor electrode 112 and the lead-out wiring 118 other than those that are conductively connected to the capacitor electrode 112 is only the thickness of the first interlayer insulating film 111. On the other hand, in the present embodiment, the distance between the connection wiring 114 ′ and the routing wiring 118 other than that which is conductively connected to the target capacitor electrode 112 is the first interlayer insulating film 111 and the second interlayer insulating film 113. Therefore, the parasitic capacitance between the capacitor electrode 112 and another conductor (the lead wiring 118) can be reduced. Further, since the connection wiring 114 ′ can be formed in the same process as the pixel electrode 114 without any additional processing, there is no possibility of increasing the manufacturing cost. Furthermore, since the pixel electrode 114 and the connection wiring 114 ′ are made of the same material, it is possible to prevent electrolytic corrosion from occurring between them.

[Third Embodiment]
FIG. 15 is a schematic configuration diagram illustrating an overall configuration of a control system (display control system) for the liquid crystal display device 100 in the electronic apparatus of the third embodiment. The electronic apparatus shown here includes a display control circuit 290 including a display information output source 291, a display information processing circuit 292, a power supply circuit 293, and a timing generator 294. Further, the liquid crystal display device 100 is provided with a panel structure 100P having the above-described configuration and a drive circuit 100D for driving the panel structure 100P. The drive circuit 100D is composed of electronic components (such as a semiconductor IC, such as the X driver 134 and the Y driver 135) that are directly mounted on the panel structure 100P. However, in addition to the above-described aspect, the drive circuit 100D may be a circuit pattern formed on the substrate surface of the panel structure 100P, or a semiconductor IC chip mounted on a circuit board conductively connected to the panel structure 100P or It can also be configured by a circuit pattern or the like.

  The display information output source 291 includes a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), a storage unit such as a magnetic recording disk or an optical recording disk, and a tuning circuit that tunes and outputs a digital image signal. The display information is supplied to the display information processing circuit 292 in the form of an image signal or the like of a predetermined format based on various clock signals generated by the timing generator 294.

  The display information processing circuit 292 includes various known circuits such as a serial-parallel conversion circuit, an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, and a clamp circuit, and executes processing of input display information to obtain image information. Are supplied to the driving circuit 100D together with the clock signal CLK. The drive circuit 100D includes a scanning line drive circuit, a signal line drive circuit, and an inspection circuit. The power supply circuit 293 supplies a predetermined voltage to each of the above-described components.

  FIG. 16 shows the appearance of a mobile phone which is an embodiment of the electronic apparatus according to the present invention. The electronic device 1000 includes an operation unit 1001 and a display unit 1002, and a circuit board 1003 is disposed inside a housing of the display unit 1002. The liquid crystal device 100 is mounted on the circuit board 1003. And it is comprised so that the display area of the said panel structure 100P can be visually recognized in the surface of the display part 1002. FIG. In this case, a backlight (not shown) is disposed behind the liquid crystal display device 100, and is configured so that transmissive display through the optical aperture 112b can be realized by light from the backlight.

  The present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification. An apparatus that includes such a change is also applicable. It is included in the technical scope of the present invention.

  For example, in the above embodiment, a transmissive liquid crystal display device can be constructed if the capacitive electrode 112 is made of a transparent conductor such as ITO, and a pure reflective liquid crystal display device can be constructed if the optical aperture 112b is not formed. Can be configured.

  In the above embodiment, a TFD (MIM) element is used as the switching element 117. However, a two-terminal nonlinear element having another structure may be used.

  Furthermore, although the liquid crystal device has been exemplified in the above embodiment, the present invention is not limited to the liquid crystal device, but the present invention can be applied to an electroluminescence device, an organic electroluminescence device, a plasma display device, an electrophoretic display device, an apparatus using an electron-emitting device (Field Emission The present invention can be similarly applied to various electro-optical devices such as Display and Surface-Conduction Electron-Emitter Display.

The schematic plan view of the 1st board | substrate of 1st Embodiment. The schematic plan view of the 2nd board | substrate of 1st Embodiment. The schematic longitudinal cross-sectional view of 1st Embodiment. The enlarged partial top view of the 1st board | substrate of 1st Embodiment. FIG. 3 is an enlarged partial perspective sectional view in the vicinity of the switching element according to the first embodiment. The schematic expanded sectional view of the part ranging from the drive area | region of 1st Embodiment to a peripheral region. FIG. 3 is a schematic enlarged plan view of a portion extending from a drive region to a peripheral region according to the first embodiment. Detailed process drawing of manufacturing process of first substrate of first embodiment The schematic process drawing of the manufacturing method of a 1st embodiment. 1 is a schematic equivalent circuit diagram of a first embodiment. The equivalent circuit diagram in 1 pixel of 1st Embodiment. FIG. 2 is a schematic equivalent circuit diagram showing the main configuration of the first embodiment. The schematic expanded sectional view of the part ranging from the drive region of 2nd Embodiment to a peripheral region. FIG. 5 is a schematic enlarged plan view of a portion extending from a drive region to a peripheral region according to a second embodiment. The schematic block diagram of the display control system of 3rd Embodiment. The schematic perspective view which shows the example of an external appearance of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Liquid crystal display device, 110 ... 1st board | substrate, 111 ... 1st interlayer insulation film, 112 ... Capacitance electrode, 112a ... Opening part, 112b ... Optical opening, 113 ... 2nd interlayer insulation film, 114 ... Pixel electrode, 114 ' Reference wiring, 115 ... Alignment film, 116 ... Image signal line, 117 ... Switching element, 118 ... Lead-out wiring, 118P, 122P ... Connection pad, 118Q ... Surface layer, 119 ... Input terminal, 120 ... Second substrate, 121 DESCRIPTION OF SYMBOLS ... Color filter, 122 ... Counter electrode, 123 ... Orientation film, 130 ... Liquid crystal layer, 131 ... Sealing material, 131a ... Conductive particle, 132, 133 ... Polarizing plate, 134 ... X driver, 135 ... Y driver

Claims (7)

A pair of substrates; an electro-optical material sandwiched between the pair of substrates; a pixel electrode disposed on one side of the electro-optical material; a two-terminal nonlinear element connected to the pixel electrode; A counter electrode facing the pixel electrode through an optical material; a drive IC for driving the electro-optical material; and a wiring arranged outside the display area of the substrate and connecting the drive IC and the counter electrode. An electro-optical device having:
A capacitor electrode that is disposed opposite to the electro-optic material with respect to the pixel electrode and forms an auxiliary capacitor between the pixel electrode,
The counter electrode is conductively connected to a wiring provided on the pixel electrode side of the electro-optic material,
An electro-optical device, wherein the capacitor electrode is conductively connected to the wiring.   A first substrate on which the two-terminal nonlinear element, the pixel electrode, the capacitor electrode, and the wiring are provided; and a second substrate on which the counter electrode is provided, wherein the electro-optic material is the first substrate. The electro-optical device according to claim 1, wherein the electro-optical device is disposed between the first substrate and the second substrate.   3. The electro-optical device according to claim 1, wherein the capacitor electrode and the wiring are conductively connected via a connection wiring formed in the same layer as the pixel electrode.   4. The electro-optical device according to claim 1, wherein the capacitor electrode is formed between the pixel electrode and the two-terminal nonlinear element. 5.   5. The device according to claim 1, further comprising: a plurality of the pixel electrodes facing the common counter electrode, wherein the capacitor electrode is integrally formed with a portion facing the plurality of pixel electrodes. The electro-optical device according to claim 1.   An electronic apparatus comprising: the electro-optical device according to claim 1; and a control unit that controls the electro-optical device. A pair of substrates; an electro-optical material sandwiched between the pair of substrates; a pixel electrode disposed on one side of the electro-optical material; a two-terminal nonlinear element connected to the pixel electrode; A counter electrode facing the pixel electrode through an optical material; a drive IC for driving the electro-optical material; and a wiring arranged outside the display area of the substrate and connecting the drive IC and the counter electrode. In a method for manufacturing an electro-optical device having:
Forming the two-terminal nonlinear element;
Forming a first interlayer insulating film on the two-terminal nonlinear element;
Forming a capacitive electrode on the first interlayer insulating film;
Forming a second interlayer insulating film on the capacitor electrode;
Forming a wiring on the pixel electrode side of the electro-optic material;
Forming the pixel electrode conductively connected to the two-terminal nonlinear element on the second interlayer insulating film, and configuring an auxiliary capacitor between the capacitor electrode and the pixel electrode;
Conductively connecting the capacitor electrode and the wiring;
Conductively connecting the wiring and the counter electrode;
An electro-optical device manufacturing method comprising:

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