JP2007011171A - Electrooptical device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device capable of maintaining high display quality by suppressing crosstalk by devising an insulating film which is a component of the electrooptical device. <P>SOLUTION: The electrooptical device has a plurality of switching elements 21 formed on a substrate 7a, data lines 19 formed on the substrate 7a, an insulating film 22 which is formed on the switching elements 21 and data lines 19 and has through holes 27 inside, pixel electrodes 24 which are formed on the insulating film 22 and connected to the switching elements 21 through the through holes 27, a liquid crystal layer 12 formed on the pixel electrodes 24, and recessed portions 41 which are formed in the insulating film 22 between other pixel electrodes 24 adjacent to the pixel electrodes 24 connected to the data lines 19 and the data lines 19. Liquid crystal 12 is put in the recessed portions 41 and the dielectric constant ε of the insulating film 22 and the dielectric constant ε2 of the liquid crystal 12 are so set that ε1>ε2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electro-optical device such as a liquid crystal display device. The present invention also relates to an electronic apparatus configured using the electro-optical device.

  Currently, electro-optical devices such as liquid crystal display devices and EL devices are widely used in various electronic devices such as mobile phones and portable information terminals. For example, an electro-optical device is used as a display unit for visually displaying various types of information related to electronic devices. In this electro-optical device, a device using liquid crystal as an electro-optical material, that is, a liquid crystal display device is known. An EL device using EL (Electro Luminescence) as an electro-optical material is also known.

  Some electro-optical devices as described above have an insulating film as a constituent element (see, for example, Patent Documents 1 to 4). Patent Document 1 discloses an interlayer insulating film for separating a layer provided with a switching element such as a TFT (Thin Film Transistor) or a wiring and a layer provided with a pixel electrode on a substrate constituting an electro-optical device. Yes. Patent Document 1 discloses a technique for reducing the parasitic capacitance between the wiring and the electrode by increasing the thickness of the interlayer insulating film and using an interlayer insulating film having a low relative dielectric constant. ing.

  Patent Document 2 discloses a technique in which an interlayer insulating film is provided between a pixel electrode and a gate electrode of a TFT element in an element substrate of an electro-optical device. Patent Document 3 discloses a technique in which an insulating film is provided between a pixel electrode and a wiring such as a source wiring or a gate wiring in an element substrate of an electro-optical device. Patent Document 4 discloses a technique in which an insulating layer is provided on a gate bus line, a source bus line, a TFT element, and a transparent electrode in an element substrate of an electro-optical device.

JP-A-10-221704 (page 4, FIG. 2) JP 2001-060067 (page 7-8, FIG. 3) JP 2002-040411 A (Page 6, FIG. 1) JP 2004-085720 A (6th page, FIG. 2)

  In the electro-optical device disclosed in each of the above documents, the insulating film is formed with a substantially uniform thickness over the entire surface of the effective display area. For this reason, a parasitic capacitance is generated between a wiring such as a data line or a scanning line formed on the substrate and a pixel electrode adjacent to the wiring, and display quality may be deteriorated. Specifically, display quality may deteriorate due to so-called crosstalk in which display in one area within the effective display area affects display in another area. More specifically, so-called vertical crosstalk occurs in which display in one area within the effective display area affects display in another area existing above and below the area on the display surface. The quality may be reduced.

  The present invention has been made in view of the above-described problems in the conventional electro-optical device, and suppresses the occurrence of crosstalk by devising an insulating film that is a component of the electro-optical device. An object of the present invention is to provide an electro-optical device and an electronic apparatus that can maintain high quality.

  The electro-optical device according to the present invention includes (1) a substrate, (2) a layer of an electro-optical material, (3) a switching element formed on the substrate, and (4) a wiring connected to the switching element. (5) an insulating film formed on the switching element and on the wiring; (6) a through hole formed in the insulating film; and (7) connected to the switching element through the through hole. A pixel electrode; and (8) the wiring, and a recess provided in the insulating film in a gap region between the pixel electrode and the other wiring adjacent to the wiring via the switching element. (9) When the dielectric constant of the insulating film is ε1 and the dielectric constant of the electro-optic material is ε2, ε1> ε2.

  In the electro-optical device according to the present invention having the above-described configuration, the concave portion is provided in the insulating film in the gap region between one wiring and the pixel electrode connected to the other wiring adjacent thereto via a switching element. An electro-optical material is accommodated in the recess. In the electro-optical device according to the present invention, when the dielectric constant of the insulating film provided with the recesses is ε1 and the dielectric constant of the electro-optical material is ε2, ε1> ε2, so that the wiring and the pixel electrode adjacent thereto are Parasitic capacitance existing between them can be reduced. As a result, occurrence of crosstalk can be suppressed and display quality can be improved.

  Hereinafter, this configuration will be considered. 8A and 8B, a switching element 102 such as a TFT (Thin Film Transistor) element, a TFD (Thin Film Diode) element, or the like is provided on a light-transmitting substrate 101. A wiring 103 such as a scanning line or a data line for transmitting a signal is provided. An insulating film 104 is provided over the element 102 and the wiring 103, a pixel electrode 105 is provided thereon, and a liquid crystal layer 107 is further provided thereon. The pixel electrode 105 and the element 102 are electrically connected by a through hole 106 formed in the insulating film 104. Various elements other than these are used in the actual electro-optical device, but illustration of elements not related to the present invention is omitted.

  FIG. 8A shows a conventional example in which no improvement is made on the insulating film. FIG. 8B shows an example of the present invention in which a recess 108 </ b> A is provided in the insulating film 104. The recess 108A is provided in parallel to the wiring 103 in the direction perpendicular to the paper surface of FIG. Further, the liquid crystal forming the liquid crystal layer 107 is accommodated in the recess 108A.

In the conventional example shown in FIG. 8A, when the interval between the wiring 103 and the adjacent pixel electrode 105 is “l”, the cross-sectional area is “S”, and the dielectric constant of the insulating film 104 is “ε1”, the wiring 103 Parasitic capacitance C generated due to the insulating film 104 existing between the pixel electrode 105 and the pixel electrode 105 is
C = ε1 × S / l (1)
It is.

On the other hand, in the configuration of the present invention shown in FIG. 8B, the length passing through the insulating film 104 in the path from the wiring 103 to the pixel electrode 105 is “11”, and the length passing through the liquid crystal in the recess 108A is “ l2 ”and the dielectric constant of the liquid crystal is“ ε2 ”, the parasitic capacitance C ′ in this case is
1 / C ′ = 1 / (ε1 × S / l1) + 1 / (ε2 × S / l2) (2)
It is.

From the above formula (1) and formula (2),
C′−C =
{Ε1 · S · l2 (ε2−ε1)} / (l1 + l2) (ε1 · l2 + ε2 · l1)
...... (3)
The following equation is obtained. Considering this equation (3), if ε2 <ε1, that is, if the dielectric constant ε2 of the liquid crystal 107 is set smaller than the dielectric constant ε1 of the insulating film 104,
C′−C <0, that is, C ′ <C
It turns out that it becomes.

  C ′ <C means that the parasitic capacitance C ′ between the wiring and the pixel electrode in the electro-optical device according to the present invention is smaller than the parasitic capacitance C at the same location in the conventional electro-optical device. . If the parasitic capacitance between the wiring and the pixel electrode can be reduced in this way, the occurrence of crosstalk in the display performed using the electro-optical device can be suppressed, and the display quality can be improved.

  In the embodiment of FIG. 8B, the recess 108A is formed by a through hole that penetrates the insulating film 104, that is, a through groove. Instead, as shown in FIG. The recess 108B may be formed by a recess having a bottom inside.

  Next, the electro-optical device according to the aspect of the invention may include a counter substrate that faces the substrate, and a light shielding member that is provided on the counter substrate so as to face a region between the pixel electrodes adjacent to each other. it can. That is, a light-shielding member, a so-called black mask, can be formed on a substrate facing the substrate on which the switching element is formed. This black mask functions effectively with respect to improving the contrast in the display using the electro-optical device. In the aspect of the present invention in which the light shielding member is formed on the counter substrate, the width of the concave portion in the gap region is preferably narrower than the width of the light shielding member. The liquid crystal layer thickness changes partially at the place where the recess containing the liquid crystal is housed, which may cause display unevenness. However, a light-shielding member that is wider than the recess should be provided for this part. By doing so, display unevenness can be prevented from being visually recognized from the outside, and high display quality can be maintained.

  Next, the electro-optical device according to the aspect of the invention may include a light reflecting film disposed between the insulating film and the pixel electrode. In this case, the pixel electrode may be formed in a rectangular shape, and the light The reflective film can be formed in a rectangular shape having a smaller area than the pixel electrode. In this case, it is desirable that the concave portion of the gap region has at least a length in the longitudinal direction of the light reflecting film. According to this configuration, the parasitic capacitance between the wiring and the pixel electrode can be sufficiently reduced to the extent that occurrence of crosstalk can be suppressed. In addition, the said recessed part can also be formed as what has the length over the whole area of the vertical direction or horizontal direction of an effective display area | region.

  Next, in the electro-optical device according to the present invention, the switching element can be a thin film diode (ie, TFD) element having an insulating film on the first electrode and a second electrode on the insulating film. In this case, the wiring is connected to the first electrode. In this case, it is desirable that the concave portion of the gap region extends in parallel to the wiring. According to this configuration, for an electro-optical device having a structure using a TFD element as a switching element, the occurrence of crosstalk is suppressed by suppressing the parasitic capacitance between the wiring and the pixel electrode, thereby improving display quality. Can do. In the electro-optical device having this configuration, the wiring can be, for example, a data line that transmits a data signal to the TFD element.

  Next, in the electro-optical device according to the aspect of the invention, the switching element may be a thin film transistor (that is, TFT) element having a semiconductor layer and a plurality of electrodes arranged with the semiconductor layer interposed therebetween. In some cases, there are two wirings, one of which is connected to one of the plurality of electrodes and the other one connected to the other one of the plurality of electrodes. In this case, it is preferable that the concave portion of the gap region extends in parallel with the one wiring and / or the other wiring. According to this configuration, for an electro-optical device having a structure using a TFT element as a switching element, the occurrence of crosstalk is suppressed by suppressing the parasitic capacitance between the wiring and the pixel electrode, thereby improving display quality. Can do. In the electro-optical device having this configuration, one of the wirings is, for example, a data line that transmits a data signal to the TFT element, and the other wiring is a scanning line that transmits a scanning signal to the TFT element. can do.

  Next, an electronic apparatus according to the present invention includes the electro-optical device according to the present invention having the above-described configuration. According to the electro-optical device of the present invention, as described above, the insulating layer existing in the gap region between one wiring and the adjacent pixel electrode is provided with a recess, and the electro-optical material is accommodated in the recess. Since the relationship between the dielectric constant ε1 of the insulating film and the dielectric constant ε2 of the electro-optic material is set to ε1> ε2, the parasitic capacitance existing between the wiring and the pixel electrode adjacent to it can be reduced. Thus, the occurrence of crosstalk can be suppressed, thereby improving the display quality. Therefore, also in the electronic apparatus of the present invention using this electro-optical device, display relating to the electronic device performed using the electro-optical device can be performed with high display quality.

(First embodiment of electro-optical device)
Hereinafter, an electro-optical device according to the invention will be described based on embodiments. Of course, the present invention is not limited to the embodiment. In the following description, various structures will be exemplified using drawings, but the structures shown in these drawings may be shown with different dimensions from the actual structures in order to show the characteristic parts in an easy-to-understand manner. There is. In the present embodiment, the present invention is applied to an active matrix liquid crystal display device that uses a TFD (Thin Film Diode) element, which is a two-terminal nonlinear resistance element, as a switching element.

  FIG. 1 shows an embodiment of a liquid crystal display device which is an example of an electro-optical device according to the invention. FIG. 2 is a side sectional view according to the line AA of FIG. 3A and 3B are enlarged views showing one pixel portion in the liquid crystal display device of FIG. 1, wherein FIG. 3A is a plan view, and FIG. 3B is a view of subpixels according to the line BB in FIG. The cross-sectional structure on the short side is shown. FIG. 4 shows a cross-sectional structure on the longitudinal side of the sub-pixel, that is, a portion indicated by an arrow E in FIG. 2 according to the line CC in FIG. FIG. 5 shows an enlarged view of the part indicated by the arrow D in FIG.

  In FIG. 1, a liquid crystal display device 1 as an electro-optical device includes a liquid crystal panel 2 as an electro-optical panel and an illumination device 3 attached to the liquid crystal panel 2. An FPC (Flexible Printed Circuit) substrate 4 is connected to the liquid crystal panel 2. Regarding the liquid crystal display device 1, the side on which the arrow A is drawn is the observation side, and the illumination device 3 is disposed on the opposite side to the observation side with respect to the liquid crystal panel 2 and functions as a backlight.

  The liquid crystal panel 2 includes a pair of substrates 7 and 8 that are bonded to each other by a rectangular or square and annular sealing material 6. The substrate 7 is an element substrate on which switching elements are formed. The substrate 8 is a color filter substrate on which a color filter is formed. As shown in FIG. 2, the sealing material 6 forms a gap, that is, a so-called cell gap G between the element substrate 7 and the color filter substrate 8. As shown in FIG. 1, a part of the sealing material 6 has a liquid crystal injection port 6a, and liquid crystal as an electro-optical material is injected between the element substrate 7 and the color filter substrate 8 through the liquid crystal injection port 6a. Is done. The injected liquid crystal forms a liquid crystal layer 12 within the cell gap G as shown in FIG. The liquid crystal injection port 6a is sealed with resin after the liquid crystal injection is completed. As a method for injecting liquid crystal, a method of supplying liquid crystal droplets into a region surrounded by a continuous annular sealing material 6 having no liquid crystal injection port can be adopted in addition to the method of performing through the liquid crystal injection port 6a as described above.

  The distance between the cell gaps G, and hence the thickness of the liquid crystal layer 12 is maintained constant by a plurality of spacers (not shown) provided in the cell gap G. The spacer can be formed by placing a plurality of spherical resin members randomly (that is, disorderly) on the surface of the element substrate 7 or the color filter substrate 8. The spacer can also be formed in a columnar shape at a predetermined position by photolithography.

  The illumination device 3 includes an LED (Light Emitting Diode) 13 as a light source and a light guide body 14. As the light source, in addition to a point light source such as an LED, a linear light source such as a cold cathode tube can be used. The light guide 14 is formed by, for example, a molding process using a light-transmitting resin as a material, the side facing the LED 13 is the light incident surface 14a, and the surface facing the liquid crystal panel 2 is the light emitting surface 14b. is there. A light reflecting layer 16 is provided on the back surface of the light guide body 14 as viewed from the observation side indicated by the arrow A, if necessary. Moreover, the light-diffusion layer 17 is provided in the light-projection surface 14b of the light guide 14 as needed.

  The element substrate 7 includes a first light-transmitting substrate 7a in FIG. The first translucent substrate 7a is formed of, for example, translucent glass or translucent plastic. A polarizing plate 18a is attached to the outer surface of the first translucent substrate 7a, for example, by sticking. If necessary, an optical element other than the polarizing plate 18a, for example, a retardation plate can be additionally provided. On the other hand, on the inner surface of the first translucent substrate 7a, as shown in FIG. 4 which is an enlarged view of a portion indicated by an arrow E, data lines 19 as wirings are formed extending in the column direction Y. . A TFD (Thin Film Diode) element 21, which is a nonlinear resistance element that functions as a switching element, is connected to the data line 19. As shown in FIG. 1, a plurality of data lines 19 are provided in parallel to each other. A plurality of TFD elements 21 are provided at equal intervals along each data line 19.

  As shown in FIG. 4, an interlayer insulating film 22 as an insulating film is formed on the TFD elements 21 and the data lines 19 so as to cover them, and a light reflecting film 23 is formed on the interlayer insulating film 22. A pixel electrode 24 is formed on the substrate, and an alignment film 26a is formed thereon. The interlayer insulating film 22 is formed, for example, by patterning a resin having translucency, photosensitivity, and insulation, such as an acrylic resin or a polyimide resin, by a photolithography process. The light reflecting film 23 is formed by patterning a light reflecting material such as Al (aluminum) or an Al alloy by a photoetching process. The pixel electrode 24 is formed by patterning a metal oxide such as ITO (Indium Tin Oxide) with a photo-etching process. The alignment film 26a is formed, for example, by applying polyimide or the like.

  As shown in FIG. 1, a plurality of light reflecting films 23 and pixel electrodes 24 are formed in a dot matrix on the element substrate 7. The light reflecting film 23 and the pixel electrode 24 are connected to the individual TFD elements 21 and provided along the data lines 19. The plurality of pixel electrodes 23 are individually formed in a dot shape as illustrated, and are formed so as to be arranged in a matrix in the vertical and horizontal directions, that is, in the matrix direction. The alignment film 26a shown in FIG. 4 is formed over substantially the entire surface of the element substrate 7 in FIG. The alignment film 26a is subjected to an alignment process such as a rubbing process, whereby the initial alignment of liquid crystal molecules in the vicinity of the element substrate 7 is determined.

  In FIG. 4, a contact hole 27 for electrically connecting the light reflecting film 23 and the TFD element 21 is formed in the interlayer insulating film 22. The contact hole 27 is formed at the same time when the interlayer insulating film 22 is formed by photolithography. The contact hole 27 is formed at a position that does not overlap the TFD element 21 in a plan view, that is, in a plan view, and a position that overlaps the light reflection film 23.

  In the present embodiment, the TFD element 21 is formed by a pair of TFD elements 25a and 25b that are electrically connected to each other in series. The first TFD element 25a is formed by overlapping the first element electrode 28, the insulating film 29, and the second element electrode 31a in that order. The second TFD element 25b is formed by stacking the first element electrode 28, the insulating film 29, and the second element electrode 31b in that order. The first element electrode 28 is made of, for example, Ta (tantalum) or Ta alloy. As the Ta alloy, for example, TaW (tantalum / tungsten) can be used. The insulating film 29 is formed by, for example, an anodic oxidation process. The second element electrodes 31a and 31b are made of, for example, Cr or molybdenum / tungsten alloy.

  The second element electrode 31 a in the first TFD element 25 a extends from the data line 19. Further, the second element electrode 31 b in the second TFD element 25 b is connected to the pixel electrode 24 through the contact hole 27 and the light reflecting film 23. Considering that a signal is transmitted from the data line 19 to the pixel electrode 24, the first TFD element 25a and the second TFD element 25b are connected in series with two TFD elements having opposite polarities. This structure is sometimes referred to as a back-to-back structure. In this embodiment, the back-to-back structure TFD element is used as described above. However, the TFD element may be formed by a single TFD element.

  In this embodiment, by providing the interlayer insulating film 22 under the pixel electrode 24, the layer of the pixel electrode 24 and the layer of the TFD element 21 are separated into different layers. This structure makes it possible to effectively use the surface of the element substrate 7 as compared with a structure in which the pixel electrode 24 and the TFD element 21 are formed in the same layer. For example, the area of the pixel electrode 24, that is, the pixel area can be increased, so that the display can be easily viewed in the liquid crystal display device 1.

  In FIG. 2, the color filter substrate 8 facing the element substrate 7 includes a second light-transmitting substrate 8 a that is rectangular or square when viewed from the observation side indicated by the arrow A. The second translucent substrate 8a is made of, for example, translucent glass, translucent plastic, or the like. A polarizing plate 18b is attached to the outer surface of the second translucent substrate 8a by, for example, sticking. If necessary, an optical element other than the polarizing plate 18b, for example, a retardation plate may be additionally provided.

  As shown in FIG. 4, a coloring element 36 is formed on the inner surface of the second translucent substrate 8 a, a light shielding member 37 is formed around the coloring element 36, and an overcoat is formed on the coloring element 36 and the light shielding member 37. A layer 38 is formed, a strip electrode 39 is formed thereon, and an alignment film 26b is formed thereon. The strip electrode 39 extends in the direction perpendicular to the paper surface of FIG. 4 (that is, the row direction X). The alignment film 26b is formed by applying polyimide or the like, for example.

  The coloring element 36 is formed in a rectangular or square dot shape when viewed from the direction of the arrow A. A plurality of the coloring elements 36 are arranged in a matrix in the row direction X (the vertical direction in FIG. 4) and the column direction Y (the left-right direction in FIG. 4) when viewed from the arrow A direction. The light shielding member 37 is formed in a lattice shape surrounding the coloring elements 36. Each of the coloring elements 36 is set to an optical characteristic that allows one of B (blue), G (green), and R (red) to pass therethrough, and the coloring elements 36 of B, G, and R are viewed from the direction of the arrow A. They are arranged in a predetermined arrangement, for example, a stripe arrangement. The stripe arrangement is an arrangement in which the same colors B, G, and R are arranged in the column direction Y, and B, G, and R are arranged alternately in the row direction X.

  Note that the arrangement of the coloring elements 36 can be any arrangement other than the stripe arrangement, for example, a mosaic arrangement, a delta arrangement, or the like. Further, the optical characteristics of the coloring element 36 are not limited to the three primary colors B, G, and R, and may be a characteristic that allows the three primary colors C (cyan), M (magenta), and Y (yellow) to pass. In the present embodiment, the light shielding member 37 is formed by overlapping any two of the three primary colors B, G, and R. However, the light shielding member 37 can be formed by overlapping three colors of B, G, and R, or can be formed by patterning a predetermined material by photolithography. As the predetermined material in this case, for example, a light shielding material such as Cr can be considered.

  The overcoat layer 38 formed on the coloring element 36 and the light shielding member 37 is to flatten the surfaces of the coloring element 36 and the light shielding member 37, and the strip electrode 39 is formed of the overcoat layer 38 thus flattened. Formed on top. The strip electrode 39 is formed by patterning a metal oxide such as ITO, for example, by a photoetching process. As shown in FIG. 1, a plurality of strip electrodes 39 are provided on the color filter substrate 8 so as to be arranged in parallel to each other. Each strip electrode 39 extends in the row direction X. In FIG. 4, the alignment film 26b formed on the strip electrode 39 is subjected to an alignment process, for example, a rubbing process, whereby the initial alignment of liquid crystal molecules in the vicinity of the color filter substrate 8 is determined.

  In FIG. 2, the plurality of pixel electrodes 24 provided on the element substrate 7 are arranged in a matrix in the row direction X and the column direction Y as seen in a plan view from the arrow A direction. On the other hand, the plurality of strip electrodes 39 provided on the color filter substrate 8 are arranged in stripes so as to overlap with the plurality of pixel electrodes 24 arranged in the column direction Y when viewed in a plan view from the arrow A direction. Thus, the pixel electrode 24 and the strip electrode 39 overlap each other when viewed from the direction of the arrow A, and the overlapped region forms a sub-pixel region D which is a minimum unit for display. A plurality of sub-pixel areas D are arranged in a matrix in the row direction X and the column direction Y to form the display area V in FIG. 1, and images such as characters, numbers, figures, etc. are displayed in the display area V. .

  When color display is performed using the coloring elements 36 composed of the three colors B, G, and R as in the present embodiment, 3 corresponding to the three coloring elements 36 corresponding to the three colors B, G, and R are displayed. One pixel is formed by one sub-pixel region D. On the other hand, when monochrome display is performed in black and white or any two colors, one pixel is formed by one sub-pixel region D. As shown in FIG. 3A, which is a plan view showing one pixel portion, the sub-pixel D is formed in a rectangular shape.

  In FIG. 4, which is a cross-sectional view taken along line CC in FIG. 3, the light reflecting film 23 is formed by, for example, a photo etching process. The light reflecting film 23 is provided in a part of the sub-pixel region D, and is not provided in the remaining region T. The region R is a part of the rectangular region in the sub-pixel region D as shown in FIG. 3A, and the region T is the remaining rectangular region in the sub-pixel region D.

  In each sub-pixel region D, a region where the light reflecting film 23 exists is a reflective display region R, and a region T where the light reflecting film 23 does not exist is a transmissive display region. In FIG. 4, the external light L0 incident from the observation side indicated by the arrow A is reflected by the reflective display region R. On the other hand, the light L1 in FIG. 4 emitted from the light guide 14 of the illumination device 3 in FIG.

  Convex portions or concave portions are formed on the surface of the interlayer insulating film 22 and corresponding to the reflective display region R in each sub-pixel region D to form a concave / convex pattern. This concavo-convex pattern is a random (that is, disordered) pattern as viewed from the direction of arrow A. The light reflecting film 23 is formed on the interlayer insulating film 22 on which such a concavo-convex pattern is formed, and itself has the same concavo-convex pattern. By forming the uneven pattern on the light reflecting film 23 in this way, the light L0 reflected by the light reflecting film 23 can be not a specular reflection but a light having scattered light or directivity.

  The light shielding member 37 formed around the coloring element 36 in the color filter substrate 8 is formed so as to surround the periphery of the sub-pixel D as indicated by a chain line in FIG. The light shielding member 37 prevents light from leaking from the periphery of the sub-pixel D and improves display contrast.

  Next, in FIG. 2, the first translucent substrate 7 a constituting the element substrate 7 has an overhanging portion 46 that projects to the outside of the color filter substrate 8. A wiring 47 is formed on the surface of the overhanging portion 46 by a photo etching process or the like. A plurality of wires 47 are formed as viewed from the direction of arrow A, and the plurality of wires 47 are arranged in parallel to each other at equal intervals in the direction perpendicular to the paper surface. Further, a plurality of external connection terminals 48 are formed at the side edges of the overhanging portion 46 so as to be arranged in parallel at equal intervals in the direction perpendicular to the paper surface. The wiring formed on the FPC board 4 shown in FIG. 1 is conductively connected to the external connection terminal 48 of FIG.

  A part of the plurality of wirings 47 becomes the data lines 19 and extends on the surface of the first translucent substrate 7a. Further, the remaining part of the plurality of wirings 47 is conductively connected to a strip electrode 39 provided on the color filter substrate 8 through a conductive material 49 included randomly (that is, disorderly) in the seal material 6. Yes. Although the conductive material 49 is schematically drawn large in FIG. 2, the conductive material 49 is actually smaller than the width of the cross section of the sealing material 6, and a plurality of conductive materials 49 are included in one cross section of the sealing material 6. Usually included.

  A driving IC 52 is mounted on the surface of the overhang portion 46 by COG (Chip On Glass) technology using an ACF (Anisotropic Conductive Film) 51. In this embodiment, a plurality of, for example, three drive ICs 52 are mounted as shown in FIG. For example, one driving IC 52 in the center transmits a data signal to the data line 19. On the other hand, the driving ICs 52 and 52 on both sides transmit a scanning signal to the strip electrode 39 formed on the color filter substrate 8.

  Next, as shown in FIG. 3B, which is a cross-sectional view taken along line BB in FIG. 3A, the interlayer insulating film 22 is not provided with a uniform thickness over the entire surface of the substrate 7a. A recess 41 is provided in a region between the data line 19 in each sub-pixel D and the pixel electrode 24 in another sub-pixel D adjacent thereto. The recess 41 is formed when the interlayer insulating film 22 is patterned by photolithography. The liquid crystal forming the liquid crystal layer 12 is accommodated in the recess 41. Thus, a parasitic capacitance adjustment region is formed by the recess 41 and the liquid crystal accommodated therein. The recess 41 is provided in parallel with the data line 19 as shown in FIG. 3A, and further extends from the end on the overhanging portion 46 side of the effective display area V to the opposite end in FIG. .

  If the dielectric constant of the interlayer insulating film 22 shown in FIG. 3B is ε1, and the dielectric constant of the liquid crystal constituting the liquid crystal layer 12 is ε2, in this embodiment, the dielectric constant is such that ε1> ε2. The material of the interlayer insulating film 22 and the liquid crystal 12 is selected. Hereinafter, a technique related to this point will be described. In FIG. 5, which is an enlarged view of a portion indicated by an arrow D in FIG. 3B, the pixel electrode in another sub-pixel region D adjacent to the sub-pixel region D from the data line 19 in one sub-pixel region D. Consider a straight path K leading to 24. In this path K, the length in the interlayer insulating film 22 is defined as l1, and the length in the recess 41 of the interlayer insulating film 22 is defined as l2.

Furthermore, if the parasitic capacitance generated along the path K is C ′ and the cross-sectional area is S, the dielectric constant of the interlayer insulating film 22 is ε1, and the dielectric constant of the liquid crystal forming the liquid crystal layer 12 is ε2. If you consider that
1 / C ′ = 1 / {ε1 × (S / l1)} + 1 / {ε2 × (S / l2)} (4)
It can be expressed as

On the other hand, if the interlayer insulating film 22 is provided on the entire surface of the substrate 7a with a uniform thickness without providing the recess 41, if the parasitic capacitance generated along the path K is C,
C = ε1 × (S / l) (5)
It can be expressed as However, l = l1 + l2.

With reference to equation (4) and equation (5),
C'-C
= {Ε1 · S · l2 (ε2−ε1)} / (l1 + l2) (ε1 · l2 + ε2 · l1)
...... (6)
Is obtained. In the present embodiment, as described above, since the material of the interlayer insulating film 22 and the liquid crystal 12 is selected so that ε1> ε2, C′−C <0 in Expression (6), and accordingly
C '<C
It becomes. As shown in FIG. 5, if the recess 41 is provided in the insulating film 22, the parasitic capacitance generated around the data line 19 can be reduced as compared with the case where the recess 41 is not provided in the insulating film 22. That is.

  According to the liquid crystal display device 1 configured as described above, in FIG. 2, when the liquid crystal display device 1 is placed in a bright outdoor room or a bright indoor room, it is a reflective type using external light such as sunlight or indoor light. Display is performed. On the other hand, when the liquid crystal display device 1 is placed outside a dark room or in a dark room, a transmissive display is performed using the lighting device 3 as a backlight.

  In the case of performing the reflection type display, in FIG. 4, the external light L0 that has entered the liquid crystal panel 2 through the color filter substrate 8 from the direction of arrow A on the observation side passes through the liquid crystal layer 12 and enters the element substrate 7. Then, the light is reflected by the light reflection film 23 in the reflective display region R and supplied to the liquid crystal layer 12 again. On the other hand, when performing the above-described transmissive display, the light source 13 of the illumination device 3 in FIG. 2 is turned on, and the light from the light source 13 is introduced into the light guide 14 from the light incident surface 14a of the light guide 14, and further the light emission. The light is emitted from the surface 14b as planar light. The emitted light is supplied to the liquid crystal layer 12 through a region where the light reflection film 23 does not exist in the transmissive display region T as indicated by a symbol L1 in FIG.

  While light is supplied to the liquid crystal layer 12 as described above, a predetermined gap specified by the scanning signal and the data signal is provided between the pixel electrode 24 on the element substrate 7 side and the strip electrode 39 on the color filter substrate 8 side. As a result, the orientation of the liquid crystal molecules in the liquid crystal layer 12 is controlled for each sub-pixel region D, and as a result, the light supplied to the liquid crystal layer 12 is modulated for each sub-pixel region D. When the modulated light passes through the polarizing plate 18b (see FIG. 2) on the color filter substrate 8 side, the passage is allowed or blocked for each sub-pixel region D according to the polarization characteristics of the polarizing plate 18b. As a result, images such as letters, numbers, figures, etc. are displayed on the surface of the color filter substrate 8 and are visually recognized from the direction of the arrow A.

In the present embodiment, as described with reference to FIG.
Dielectric constant ε1 of the interlayer insulating film 22> dielectric constant ε2 of the liquid crystal 12
The material of the interlayer insulating film 22 and the liquid crystal 12 is selected so that the parasitic capacitance C ′ generated around the data line 19 is made smaller than the parasitic capacitance C when the recess 41 is not provided, that is, C '<C was able to be made. Since the parasitic capacitance can be reduced in this manner, the occurrence of crosstalk, particularly vertical crosstalk, can be suppressed, and a clear display can be obtained.

  In this embodiment, the recess 41 is formed by a groove penetrating the insulating film 22 as shown in FIG. 3B. Instead, the recess 41 is formed in the insulating film 22 by a recess having a bottom inside. You may do it.

  In this embodiment, the width W0 of the recess 41 provided in the element substrate 7 is set to be narrower than the width W1 of the light shielding member 37 provided in the color filter substrate 8. Although the liquid crystal layer thickness changes partially at the place where the recess 41 containing the liquid crystal 12 is provided, display unevenness may occur. However, the light shielding member having a width wider than the recess 41 corresponding to this portion. If 37 is provided, display unevenness can be prevented from being visually recognized from the outside, and high display quality can be maintained.

  Further, in the present embodiment, the recess 41 shown in FIG. 3A is provided without a break from the end side of the effective display area V on the IC mounting side to the end side on the opposite side in FIG. Thus, if the recess 41 is provided without a break from one edge of the effective display region V to the opposite edge, it is very effective in reducing parasitic capacitance caused by the insulating film 22. It should be noted that the recess 41 does not necessarily have to be provided in the effective display area V in such a manner, and may be provided with a cut, that is, intermittently depending on circumstances. However, the recess 41 is desirably set to a length longer than the length L2 of the light reflecting film 23 in the longitudinal direction in FIG. In this way, the parasitic capacitance between the data line 19 and the pixel electrode 24 can be sufficiently reduced to the extent that occurrence of crosstalk can be suppressed.

(Second embodiment of electro-optical device)
Next, another embodiment of the electro-optical device according to the invention will be described with reference to FIGS. Of course, the present invention is not limited to the embodiment. Further, the structures shown in these drawings may be shown with dimensions different from those of the actual structures in order to show the characteristic parts in an easy-to-understand manner. In the present embodiment, the present invention is applied to an active matrix liquid crystal display device using a TFT (Thin Film Transistor) element, which is a three-terminal switching element, as a switching element.

  The overall configuration of the liquid crystal display device according to this embodiment is substantially the same as that of the previous embodiment shown in FIGS. The difference is that the TFD element 21 (see FIG. 4) is used as the switching element in the previous embodiment, but the TFT element is used instead in this embodiment. Some changes have been made. The TFT elements, that is, switching elements are formed on the element substrate 7 in FIG. 2, and the color filters, that is, the coloring elements are formed on the color filter substrate 8, as in the previous embodiment.

  FIG. 6A shows a configuration in the case where the vicinity of one sub-pixel region D indicated by the arrow E on the liquid crystal side surface of the element substrate 7 of FIG. . FIG. 6B shows a cross-sectional structure on the short side of the sub-pixel region D according to the line FF in FIG. FIG. 7 shows a cross-sectional structure in the longitudinal direction of the sub-pixel region D according to the GG line of FIG. In FIG. 6B, a cell gap G is formed between the element substrate 7 and the color filter substrate 8, and the liquid crystal layer 12 is formed in the cell gap G.

  A colored element 56 is formed on a translucent substrate 8a that is a component of the color filter substrate 8, a light shielding member 57 is formed so as to surround the colored element 56, and an overcoat layer 58 is formed thereon, on which A common electrode 59 is formed, and an alignment film 76b is formed thereon. The common electrode 59 used in the present embodiment is provided in a plane with a uniform thickness on the substrate 8a.

  The TFT element used in this embodiment is an amorphous TFT element. This TFT element includes a gate electrode 62 formed on a substrate 7a, which is a constituent element of the element substrate 7, and a TFT 61 as shown in FIG. A gate insulating film 63 formed on the substrate 7a so as to cover the semiconductor layer 64 made of amorphous silicon (a-Si) formed on the gate electrode 62 via the gate insulating film 63; A source electrode 65 formed to be connected to one side and a drain electrode 66 formed to be connected to the other side of the semiconductor layer 64 are provided.

  The source electrode 65 extends from a source electrode line 65 ′ as a wiring extending in the direction perpendicular to the paper surface of FIG. 6B (the vertical direction of the paper surface of FIG. 6A). Further, the gate electrode 62 extends from a gate electrode line 62 'as a wiring extending in the left-right direction in FIG. 6B (left-right direction in FIG. 6A). The source electrode line 65 ′ and the gate electrode line 62 ′ are formed so as to be orthogonal to each other via an insulating film as shown in FIG. The source electrode line 65 'is electrically connected to one of the three driving ICs 52 in FIG. 1 and supplied with a data signal. Further, the gate electrode line 62 'is electrically connected to two on both sides of the three driving ICs 52 in FIG.

  In the present embodiment in which the TFT element is used as a switching element, both the data line and the scanning line are formed on the element substrate 7, so that the conductive material 49 dispersed in the sealing material 6 in FIG. 2 is used. A vertical conduction structure is not required.

  In FIG. 6B, an interlayer insulating film 72 is provided on the TFT element 61 and the gate insulating film 63, a light reflecting film 73 is formed on the interlayer insulating film 72, a pixel electrode 74 is formed thereon, and a pixel electrode 74 is formed thereon. An alignment film 76a is formed. In FIG. 7 showing a cross section orthogonal to FIG. 6B, a region R where the light reflecting film 73 exists in the sub-pixel region D is a reflective display region, and a region T where the light reflecting film 73 does not exist is a transmissive display region. It is. In this embodiment, the material of the interlayer insulating film 72 and the material of the liquid crystal 12 are selected so that ε1> ε2 when the dielectric constant of the interlayer insulating film 72 is ε1 and the dielectric constant of the liquid crystal is ε2.

  In the present embodiment, in FIG. 6B, the source electrode line 65 ′ that transmits a data signal to the TFT element 61 in a certain sub-pixel region D and the other sub-pixel region D adjacent to the sub-pixel region D A recess 41 a extending in the column direction Y is provided in the insulating film 72 between the pixel electrode 74 and the pixel electrode 74. Liquid crystal constituting the liquid crystal layer 12 is accommodated in the recess 41a. A straight path K from the source electrode line 65 ′ to the adjacent pixel electrode 74 is divided into a region having a length 11 passing through the insulating film 72 and a region having a length 12 passing through the liquid crystal 12 in the recess 41 a. By providing the recess 41a in this way, the parasitic capacitance around the source electrode line 65 'can be reduced.

  In FIG. 7, the gate electrode line 62 ′ connected to the gate electrode 62, which is a component of the TFT element 61, extends in the direction perpendicular to the paper surface of FIG. 7 (that is, the horizontal direction of the paper surface of FIG. 6A). The gate electrode line 62 ′ transmits a scanning signal to the TFT element 61. A recess 41b extending in the row direction X is formed in the insulating film 72 between the gate electrode line 62 ′ in a certain subpixel region D and the pixel electrode 74 in another subpixel region D adjacent to the subpixel region D. Provided. Liquid crystals constituting the liquid crystal layer 12 are accommodated in the recesses 41b. A straight path K from the gate electrode line 62 ′ to the adjacent pixel electrode 74 is divided into a region having a length 11 passing through the insulating film 72 and a region having a length 12 passing through the liquid crystal 12 in the recess 41 b. By providing the recess 41b in this way, the parasitic capacitance around the gate electrode line 62 'can be reduced.

  As described above, in the liquid crystal display device of the present embodiment in which the two wirings, ie, the gate electrode line 62 ′ and the source electrode line 65 ′, which are orthogonal to each other, are provided on the element substrate 7, FIG. As shown in FIG. 7 and FIG. 7, since the two concave portions 41a and 41b parallel to each of the respective wirings are provided, the parasitic capacitance can be reduced with respect to any of the wirings. It is possible to reliably reduce and perform a clear display.

(Other Embodiments Regarding Electro-Optical Device)
The embodiment described above relates to a liquid crystal display device using a TFD element as a two-terminal switching element as a switching element, and a liquid crystal display device using an amorphous TFT element as a three-terminal switching element as a switching element. Is. In addition to those embodiments, the electro-optical device according to the invention can be applied to a liquid crystal display device using a high-temperature polysilicon TFT element, a low-temperature polysilicon TFT element, or the like as a switching element.

  The present invention can also be applied to electro-optical devices other than liquid crystal display devices, for example, organic EL devices using organic EL (Electro Luminescence) as an electro-optical material, plasma displays using plasma gas as an electro-optical material, and the like.

  In the above-described embodiment, for example, as shown in FIGS. 3B and 4, the light reflecting film 23 that forms the reflective display region R is provided separately from the pixel electrode 24, but instead of this configuration, It is also possible to form the pixel electrode itself from a light-reflective material and also serve as a light reflection film, and omit a dedicated light reflection film. In this case, the recess provided in the insulating film functions to reduce the parasitic capacitance between the pixel electrode formed of the light reflecting material and the wiring such as the data line.

(Embodiment of electronic device)
Hereinafter, an electronic device according to the present invention will be described with reference to embodiments. In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment.

  FIG. 9 shows an embodiment of an electronic apparatus according to the invention. The electronic device shown here includes a liquid crystal device 121 and a control circuit 120 that controls the liquid crystal device 121. The control circuit 120 includes a display information output source 124, a display information processing circuit 125, a power supply circuit 126, and a timing generator 127. The liquid crystal device 121 includes a liquid crystal panel 122 and a drive circuit 123.

  The display information output source 124 includes a memory such as a RAM (Random Access Memory), a storage unit such as various disks, a tuning circuit that tunes and outputs digital image signals, and various clock signals generated by the timing generator 127. The display information processing circuit 125 is supplied with display information such as an image signal in a predetermined format.

  Next, the display information processing circuit 125 includes a number of well-known circuits such as an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, a clamp circuit, and the like, executes processing of input display information, and outputs an image signal. It is supplied to the drive circuit 123 together with the clock signal CLK. Here, the drive circuit 123 is a general term for an inspection circuit and the like together with a scanning line drive circuit and a data line drive circuit. The power supply circuit 126 supplies a predetermined power supply voltage to each of the above components.

  The liquid crystal device 121 includes, for example, a liquid crystal display device having the recess 41 shown in FIGS. 3A and 3B, or the recess 41a shown in FIGS. 6A, 6B, and 7. The liquid crystal display device having 41b can be used. According to these liquid crystal display devices, a recess is provided in an insulating layer existing between a wiring such as a data line, a gate electrode line, a source electrode line, and the adjacent pixel electrode, and liquid crystal is accommodated in the recess. In addition, since the relationship between the dielectric constant ε1 of the insulating film and the dielectric constant ε2 of the liquid crystal is set to ε1> ε2, the parasitic capacitance existing between the wiring and the pixel electrode adjacent thereto can be reduced. The occurrence of crosstalk can be suppressed, thereby improving the display quality. Therefore, also in the electronic apparatus according to the present embodiment using this liquid crystal display device, display relating to the electronic apparatus performed using the liquid crystal display device can be performed with high display quality.

  Next, FIG. 10 shows a mobile phone which is another embodiment of the electronic apparatus according to the present invention. A cellular phone 130 shown here includes a main body 131 and a display body 132 provided on the main body 131 so as to be opened and closed. A display device 133 configured by an electro-optical device such as a liquid crystal display device is disposed inside the display body 132, and various displays related to telephone communication can be visually recognized on the display body 132 on the display screen 134. Operation buttons 136 are arranged on the main body 131.

  An antenna 137 is attached to one end portion of the display body 132 so as to be extendable. A speaker (not shown) is arranged inside the receiver 138 provided at the upper part of the display body 132. Further, a microphone (not shown) is built in the transmitter 139 provided at the lower end of the main body 131. A control unit for controlling the operation of the display device 133 is stored in the main unit 131 or the display unit 132 as a part of the control unit that controls the entire mobile phone or separately from the control unit. The

  The display device 133 is, for example, a liquid crystal display device provided with the recess 41 shown in FIGS. 3A and 3B in the insulating film 22, or FIGS. 6A, 6 B, and 7. The liquid crystal display device having the recesses 41a and 41b shown in FIG. According to these liquid crystal display devices, a recess is provided in an insulating layer existing between a wiring such as a data line, a gate electrode line, a source electrode line, and the adjacent pixel electrode, and liquid crystal is accommodated in the recess. In addition, since the relationship between the dielectric constant ε1 of the insulating film and the dielectric constant ε2 of the liquid crystal is set to ε1> ε2, the parasitic capacitance existing between the wiring and the pixel electrode adjacent thereto can be reduced. The occurrence of crosstalk can be suppressed, thereby improving the display quality. Therefore, also in the mobile phone according to the present embodiment using this liquid crystal display device, display related to the mobile phone using the liquid crystal display device can be performed with high display quality.

(Other embodiment regarding an electronic device)
In addition to the above-described mobile phones and the like as electronic devices, personal computers, liquid crystal televisions, viewfinder type or monitor direct view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, word processors, Examples include workstations, video phones, and POS terminals.

1 is a perspective view showing an embodiment of an electro-optical device according to the invention. It is sectional drawing according to the AA line of FIG. It is a figure which shows one pixel part in the apparatus of FIG. 1, Comprising: (a) is the top view, (b) is sectional drawing which shows the transversal side cross section of a pixel according to the BB line of (a). It is sectional drawing which shows the longitudinal cross-section of a pixel according to CC line of Fig.3 (a). FIG. 4 is an enlarged view of a portion indicated by an arrow D in FIG. FIG. 6 is a diagram illustrating a main part of another embodiment of the electro-optical device according to the invention. It is sectional drawing according to the GG line of Fig.6 (a). It is a figure for demonstrating the main structures of this invention. It is a block diagram which shows one Embodiment of the electronic device which concerns on this invention. It is a perspective view which shows other embodiment of the electronic device which concerns on this invention.

Explanation of symbols

1. 1. liquid crystal display device (electro-optical device), LCD panel (electro-optical panel),
3. 3. lighting device; FPC, 6. 6. sealing material Element substrate,
7a. 7. a first translucent substrate; Color filter substrate, 8a. A second translucent substrate,
12 Liquid crystal layer, 13. LED, 14. Light guide, 18a, 18b. Polarizer,
19. 20. Data line (wiring) TFD element (switching element),
22. Interlayer insulating film, 23. Light reflection film, 24. Pixel electrodes,
25a, 25b. TFD elements, 26a, 26b. Alignment film,
27. Contact hole, 36. Coloring elements, 37. Light shielding member,
38. Overcoat layer, 39. Strip electrode, 41. Recess, 52. Driving IC,
61. TFT element (switching element),
62. A gate electrode, 62 '. Gate electrode line (wiring), 63. Gate insulation film,
64. Semiconductor layer, 65. Source electrode, 65 '. Source electrode wire (wiring),
66. Drain region, 72. Interlayer insulating film 73. Light reflecting film, 74. Pixel electrodes,
76a, 76b. Alignment film, 121. Liquid crystal display devices (electro-optical devices),
130. Mobile phone (electronic device), 133. Display device (electro-optical device,
D. A sub-pixel region; Cell gap; Straight path, L0, L1. light,
L2. The length of the light reflecting film in the longitudinal direction; Reflective display area, T.I. Transparent display area,
V. Display area, W0. The width of the recess, W1. Width of shading member

Claims (9)

A substrate,
A layer of electro-optic material;
A switching element formed on the substrate;
Wiring connected to the switching element;
An insulating film formed on the switching element and on the wiring;
A through hole formed in the insulating film;
A pixel electrode connected to the switching element through the through hole;
A recess provided in the insulating film in a gap region between the wiring and the pixel electrode connected to the other wiring adjacent to the wiring via the switching element;
An electro-optical device, wherein ε1> ε2, where ε1 is a dielectric constant of the insulating film and ε2 is a dielectric constant of the electro-optical material. The electro-optical device according to claim 1.
A counter substrate facing the substrate;
A light shielding member provided on the counter substrate so as to face a region between the pixel electrodes adjacent to each other;
The electro-optical device, wherein the width of the concave portion in the gap region is narrower than the width of the light shielding member. The electro-optical device according to claim 1 or 2,
A light reflecting film disposed between the insulating film and the pixel electrode;
The pixel electrode is formed in a rectangular shape,
The light reflecting film is formed in a rectangular shape having a smaller area than the pixel electrode,
The electro-optical device, wherein the concave portion of the gap region has at least a length in a longitudinal direction of the light reflecting film. The electro-optical device according to any one of claims 1 to 3,
The switching element is a thin film diode having an insulating film on the first electrode and a second electrode on the insulating film,
The wiring is connected to the first electrode;
The electro-optical device, wherein the concave portion of the gap region extends in parallel to the wiring.   5. The electro-optical device according to claim 4, wherein the wiring is a data line for transmitting a data signal. The electro-optical device according to any one of claims 1 to 3,
The switching element is a thin film transistor having a semiconductor layer and a plurality of electrodes arranged with the semiconductor layer interposed therebetween,
There are two wirings, one connected to one of the plurality of electrodes, the other connected to the other one of the plurality of electrodes,
The electro-optical device, wherein the concave portion of the gap region extends in parallel to the one wiring and / or the other wiring.   7. The electro-optical device according to claim 6, wherein the one wiring is a data line for transmitting a data signal, and the other wiring is a scanning line for transmitting a scanning signal.   8. The electro-optical device according to claim 1, wherein the concave portion of the gap region is a through-hole penetrating the insulating film, or a concave portion having a bottom in the insulating film. An electro-optical device. An electronic apparatus comprising the electro-optical device according to claim 1.

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