JP2005266195A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device in which a liquid crystal is aligned with sufficient stability and which is manufactured with a process simpler than any conventional process by using a comparatively simple construction with a groove structure for alignment control mounted only on a substrate of one side. <P>SOLUTION: The liquid crystal display device has a first substrate 110a, a second substrate 110b placed so as to face the first substrate, a liquid crystal layer 120 interposed between the first and second substrates, a first electrode 111 formed on the first substrate, a second electrode 131 formed on the second substrate, an interlayer insulating film 115 placed between the first electrode and the first substrate, and a groove structure 115a formed on the interlayer insulating film. The liquid crystal display device is equipped with a plurality of pixels each including the first electrode, the second electrode and the liquid crystal layer disposed between the first and second electrodes. A shading region surrounds each of the plurality of pixels, and the groove structure is arranged regularly in the shading region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device suitably used for a personal digital assistant (for example, PDA), a mobile phone, an in-vehicle liquid crystal display, a digital camera, a personal computer, an amusement device, a television, and the like.

  In recent years, liquid crystal display devices have been widely used for information devices such as notebook personal computers, mobile phones, electronic notebooks, or camera-integrated VTRs equipped with a liquid crystal monitor, taking advantage of their thinness and low power consumption. ing.

  As a display mode capable of realizing a high contrast and a wide viewing angle, a vertical alignment mode using a vertical alignment type liquid crystal layer has attracted attention. The vertical alignment type liquid crystal layer is generally formed using a vertical alignment film and a liquid crystal material having negative dielectric anisotropy.

  For example, Patent Document 1 discloses that an oblique electric field is generated around an opening provided in a counter electrode facing a pixel electrode via a liquid crystal layer, and liquid crystal around the liquid crystal molecules in a vertically aligned state in the opening. A liquid crystal display device in which viewing angle characteristics are improved by tilting molecules is disclosed.

  However, in the configuration described in Patent Document 1, it is difficult to form an oblique electric field in the entire region in the pixel. As a result, a region in which the response of the liquid crystal molecules to the voltage is delayed occurs in the pixel, and an afterimage phenomenon occurs. The problem of appearing arises.

  In order to solve this problem, Patent Document 2 discloses a liquid crystal display device having a plurality of liquid crystal domains exhibiting a radially inclined alignment in a pixel by providing openings regularly arranged in the pixel electrode or the counter electrode. doing.

  Furthermore, Patent Document 3 discloses a technique for stabilizing the alignment state of a liquid crystal domain having an inclined radial alignment that appears around a convex portion by providing a plurality of convex portions regularly in a pixel. . Further, this document discloses that the display characteristics can be improved by regulating the alignment of liquid crystal molecules using an oblique electric field by an opening provided in the electrode, together with the alignment regulating force by the convex part.

  Further, in Patent Document 4, a groove structure is provided in a pixel (at least in a region to which a voltage for display is applied), and the region is divided by using the alignment regulating force of the side surface portion of the groove structure. Discloses a technical disclosure relating to a liquid crystal display device in which an axially symmetric alignment domain is formed. When this technique is applied to a plasma addressed liquid crystal display device, a voltage is easily applied to the groove structure portion where the thickness of the liquid crystal layer is large, so that the drive voltage can be reduced and the response speed can be improved.

  On the other hand, in recent years, liquid crystal display devices capable of high-quality display both outdoors and indoors have been proposed (for example, Patent Document 5 and Patent Document 6). This liquid crystal display device is referred to as a transflective liquid crystal display device, and has a reflective region in a pixel for displaying in a reflective mode and a transmissive region for displaying in a transmissive mode.

  The transflective liquid crystal display devices currently on the market use the ECB mode, the TN mode, and the like. However, in Patent Document 3, the vertical alignment mode is not limited to the transmissive liquid crystal display device but also the transflective liquid crystal. A configuration applied to a display device is also disclosed. Further, in Patent Document 7, in a semi-transmissive liquid crystal display device having a vertical alignment type liquid crystal layer, an insulating layer provided in order to make the thickness of the liquid crystal layer in the transmissive region twice the thickness of the liquid crystal layer in the reflective region. A technique for controlling the alignment (multiaxial alignment) of liquid crystals by the formed recesses is disclosed. A configuration is disclosed in which the recess is formed in, for example, a regular octagon, and a protrusion (projection) or a slit (electrode opening) is formed at a position facing the recess via the liquid crystal layer (for example, FIG. 3 and FIG. 16).

Further, in order to improve display quality in the reflection mode, a technique for forming a diffuse reflection layer having excellent diffuse reflection characteristics has been studied. For example, Patent Document 8 discloses a technique for obtaining good diffuse reflection characteristics by forming fine irregularities randomly arranged on the surface of the reflective electrode through a photolithography process using a two-layer photosensitive resin film. Is disclosed. Further, in Patent Document 9, for the purpose of simplifying the manufacturing process, a single layer of photosensitive resin is used to expose and develop a contact hole and a photomask for forming fine irregularities. Thus, a technique for forming a reflective electrode having a fine uneven shape is disclosed.
JP-A-6-301036 JP 2000-47217 A JP 2003-167253 A JP 2000-98393 A Japanese Patent No. 29555277 US Pat. No. 6,195,140 JP 2002-350853 A JP-A-6-75238 Japanese Patent Laid-Open No. 9-90426

  In the technique disclosed in Patent Document 2 or Patent Document 3, a plurality of liquid crystal domains are formed by providing convex portions or openings in a pixel (that is, divided into pixels), and the alignment regulation force on liquid crystal molecules is strengthened. However, according to the study of the present inventors, in order to obtain a sufficient alignment regulating force, alignment regulating structures such as convex portions and openings are formed on both sides of the liquid crystal layer (the liquid crystal layer side of a pair of substrates facing each other). There is a problem that the manufacturing process becomes complicated. In addition, when the alignment regulating structure is provided in the pixel, the effective aperture ratio of the pixel may be reduced, or the contrast ratio may be reduced due to light leakage from the periphery of the convex portion in the pixel. In the case where the alignment regulation structure is provided on both the substrates, since it is affected by the alignment margin of the substrates, the effective aperture ratio and / or the contrast ratio are further reduced.

  Further, when the technique described in Patent Document 4 is used, a groove structure is formed in the pixel (or at least in a region to which a voltage for display is applied), so that the vicinity of the inclined portion of the groove structure is formed. Thus, there is a problem that light leakage occurs when no voltage is applied, resulting in a decrease in contrast ratio or a decrease in effective aperture ratio.

  Further, in the technique disclosed in Patent Document 6, it is necessary to arrange a convex part or an electrode opening on the side opposite to the concave part provided in order to control the multiaxial orientation. Occur.

  In addition, for example, when the reflective electrode is formed using the method described in Patent Document 7 or 8 in order to improve the display quality of the reflective mode of the transflective liquid crystal display device, the manufacturing process becomes complicated. There is. That is, it is necessary to form not only convex portions for regulating the orientation but also fine irregularities for improving the diffuse reflection characteristics, leading to an increase in the cost of the liquid crystal display device.

  The present invention has been made in view of the above points, and its purpose is to provide a relatively simple configuration in which a groove structure for alignment control is provided only on one substrate, and the alignment of liquid crystals is sufficiently achieved. An object of the present invention is to provide a liquid crystal display device that can be stabilized and manufactured by a simpler process than before and a manufacturing method thereof.

  The liquid crystal display device of the present invention includes a first substrate, a second substrate provided to face the first substrate, a liquid crystal layer provided between the first substrate and the second substrate, An interlayer insulating film having a first electrode formed on the first substrate, a second electrode formed on the second substrate, and a groove structure provided between the first electrode and the first substrate. Each including a plurality of pixels including the first electrode, the second electrode, and the liquid crystal layer provided between the first electrode and the second electrode, A light shielding region is provided around each pixel, and the groove structure is regularly arranged at least in the light shielding region. The groove structure may be an integrally formed groove or a plurality of grooves separated from each other.

  In one embodiment, a plurality of switching elements electrically connected to the first electrode are further provided on the first substrate, and at least a part of the switching elements is covered with the interlayer insulating film.

  In one embodiment, the liquid crystal layer is a vertical alignment type liquid crystal layer, and forms at least one liquid crystal domain including liquid crystal molecules aligned in different directions when at least a predetermined voltage is applied.

  In one embodiment, the first electrode and / or the second electrode has a plurality of openings or notches formed at predetermined positions.

  In one embodiment, the first electrode and / or the second electrode has at least two openings and at least one notch formed at predetermined positions.

  In one embodiment, the plurality of openings or notches are formed only in the first electrode.

  In one embodiment, the liquid crystal layer is a vertical alignment type liquid crystal layer, and forms at least two liquid crystal domains each exhibiting axial symmetry alignment when at least a predetermined voltage is applied. The central axis of each axially symmetric orientation is formed in or near the plurality of openings.

  In one embodiment, the liquid crystal layer is a vertical alignment type liquid crystal layer, and forms at least two liquid crystal domains each having an axially symmetric alignment when at least a predetermined voltage is applied. It is also arranged at the boundary between a pair of liquid crystal domains adjacent to each other in at least two liquid crystal domains.

  In one embodiment, each of the plurality of pixels has a further light shielding region, and the groove structure arranged at the boundary is provided in the further light shielding region. The further light shielding region is constituted by, for example, an auxiliary capacitance wiring.

  In one embodiment, the first electrode includes a transparent electrode that defines a transmissive region and a reflective electrode that defines a reflective region.

  In one embodiment, the groove structure is also disposed at a boundary between the transmission region and the reflection region.

  In one embodiment, the first substrate and / or the second substrate and the pair of polarizing plates have a pair of polarizing plates disposed so as to face each other with the first substrate and the second substrate interposed therebetween. And at least one biaxial optically anisotropic medium layer.

  In one embodiment, the liquid crystal display device further includes a pair of polarizing plates disposed so as to face each other with the first substrate and the second substrate interposed therebetween, and the first substrate and / or the second substrate and the pair of polarizations It further has at least one uniaxial optically anisotropic medium layer between the plates.

  A method of manufacturing a liquid crystal display device according to the present invention includes a first substrate, a second substrate provided to face the first substrate, and a liquid crystal provided between the first substrate and the second substrate. A first electrode formed on the first substrate; a circuit element electrically connected to the first electrode; a second electrode formed on the second substrate; and the first electrode; An interlayer insulating film provided between the first substrate and having a groove structure, each of which is between the first electrode, the second electrode, and the first electrode and the second electrode. A liquid crystal display device comprising: a plurality of pixels including the liquid crystal layer provided; a light shielding region around each of the plurality of pixels; and the groove structure regularly disposed at least in the light shielding region A method of forming a circuit element on a first substrate, and a positive type covering the circuit element A step of forming a photosensitive resin film; a step of exposing the photosensitive resin film; forming a predetermined region having different exposure amounts; and developing the exposed photosensitive resin film A step of forming the interlayer insulating film having a contact hole exposing a part of the circuit element and the groove structure, and a step of forming a first electrode on the interlayer insulating film. And

  In one embodiment, the step of forming the interlayer insulating layer includes a step of forming a first region having a substantially flat surface and a second region having a concavo-convex shape, and forming the first electrode. The step of forming includes a step of forming a transparent electrode on the interlayer insulating film in the first region and a step of forming a reflective electrode on the interlayer insulating film in the second region.

  In one embodiment, the exposure step uses a first photomask to form the second region and the region to be the groove structure and other regions, and the other region, And a second exposure step of forming the first region and the contact hole using a second photomask.

  In one embodiment, the step of forming the first electrode and / or the second electrode includes a step of forming a conductive film and a step of patterning the conductive film. The step of patterning includes the step of forming the first electrode. Including a step of forming a plurality of openings or notches at predetermined positions of one electrode and / or the second electrode.

  In the liquid crystal display device of the present invention, the groove structure is provided on the liquid crystal layer side of the first substrate on which the first electrode (for example, pixel electrode) is formed. The groove structure is formed in an interlayer insulating film provided between the first substrate and the first electrode, and is disposed at least in a light shielding region around the pixel. The direction in which the liquid crystal molecules are tilted by the electric field is defined by the anchoring action (alignment regulating force) on the inclined side surface of the groove structure, and as a result, when at least a predetermined voltage (voltage above the threshold) is applied, the groove structure Thus, at least one liquid crystal domain including liquid crystal molecules having different alignment directions is stably formed in a region substantially surrounded by. Accordingly, the orientation of the liquid crystal molecules can be sufficiently stabilized with a simpler structure than before, and a display quality equal to or higher than that of the conventional one can be obtained. Furthermore, since the trench structure is formed in the interlayer insulating film, it can be manufactured by a simpler process than before. In addition, light leakage from the vicinity of the groove structure disposed outside the pixel does not affect the reduction in contrast ratio. As a matter of course, since it is not necessary to apply a voltage for display to the liquid crystal layer outside the pixel, it is not particularly necessary to form a pixel electrode on the groove structure disposed outside the pixel, and between adjacent pixel electrodes. Since the pixel electrodes can be arranged close to each other within a range in which the short circuit can be prevented, a high effective aperture ratio can be obtained.

  Furthermore, when the opening or notch is provided in the first electrode and / or the second electrode, the orientation of the liquid crystal molecules can be further stabilized by the influence of an oblique electric field generated around the opening or notch. As the liquid crystal layer, a vertical alignment type liquid crystal layer can be preferably used, and a stable axially symmetric alignment domain can be formed by the groove structure (and the opening or notch). Note that at least one liquid crystal domain may be formed in each pixel, but two or more liquid crystal domains may be formed depending on the size and shape of the pixel. For a typical rectangular pixel, It is preferable to form two or more liquid crystal domains.

  When two or more liquid crystal domains are formed in a pixel, a groove structure may be arranged at the boundary between a pair of adjacent liquid crystal domains. At this time, in the case where the pixel has a further light-shielding region (for example, auxiliary capacitance wiring), by providing the groove structure in the further light-shielding region, it is possible to suppress a decrease in contrast ratio due to light leakage.

  The opening has an effect of fixing and stabilizing the position of the central axis of the axially symmetric alignment domain. The opening may be provided in one of the first electrode and the second electrode, but providing the opening in both the first electrode and the second electrode can increase the effect of fixing and stabilizing the position of the central axis. it can. The openings provided in the first electrode and the second electrode are preferably provided at positions that overlap each other when viewed from the normal direction of the substrate. On the other hand, the notch is preferably provided only in the first electrode. In addition, the openings and notches formed in the electrodes can be formed in the process of patterning each electrode, unlike the structural orientation regulating structure such as the groove structure and the convex part, which increases the number of manufacturing processes. There is no. According to the present invention, a stable axially symmetric alignment domain can be formed without providing an alignment regulating structure such as a groove structure or a convex portion on the second substrate.

  A liquid crystal display device according to an embodiment of the present invention includes a first substrate (for example, a TFT side glass substrate), a second substrate (for example, a color filter side glass substrate) provided to face the first substrate, and these substrates. A liquid crystal layer (for example, a vertical alignment type liquid crystal layer) provided between the first substrate, a first electrode (for example, a pixel electrode) formed on the first substrate, and a second electrode (for example, a counter electrode) formed on the second substrate. And an interlayer insulating film having a groove structure provided between the first electrode and the first substrate. Each of the plurality of pixels included in the liquid crystal display device includes a first electrode, a second electrode, and a liquid crystal layer provided between the first electrode and the second electrode. A light shielding region is provided, and the groove structures are regularly arranged at least in the light shielding region. The light shielding region is defined by, for example, a gate signal wiring or a source signal wiring connected to a switching element (for example, TFT) provided on the first substrate.

  The present invention can realize a liquid crystal display device capable of displaying with a wide viewing angle and a high contrast ratio, particularly when a vertical alignment type liquid crystal layer is used and a plurality of axially symmetric alignment domains are formed in each pixel. Therefore, in the following, an embodiment of the present invention will be described taking a liquid crystal display device using a vertical alignment type liquid crystal layer (so-called VA mode liquid crystal display device) as an example. However, the present invention is not limited to this, and at least a predetermined voltage is described. Can be applied to a liquid crystal display device in which at least one liquid crystal domain including liquid crystal molecules aligned in different directions is formed in a pixel. When a plurality of liquid crystal domains are formed in a pixel, the alignment direction of the liquid crystal molecules in each liquid crystal domain may be one direction. From the viewpoint of viewing angle characteristics, the liquid crystal molecules preferably have liquid crystal domains having four or more alignment directions, and an axially symmetric alignment domain is exemplified below.

  In the following embodiments, transmissive and transflective liquid crystal display devices are exemplified, but the present invention can be applied to reflective display devices.

  The configuration of the liquid crystal display device according to the embodiment of the present invention will be specifically described below with reference to the drawings.

(Transmission type liquid crystal display)
First, the configuration of a transmissive liquid crystal display device 100 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram schematically showing the configuration of one pixel of the transmissive liquid crystal display device 100, (a) is a plan view, and (b) is 1B-1B ′ in FIG. 1 (a). It is sectional drawing along a line.

  The liquid crystal display device 100 includes a transparent substrate (for example, a glass substrate) 110a, a transparent substrate 110b provided to face the transparent substrate 110a, and a vertical alignment type liquid crystal layer provided between the transparent substrates 110a and 110b. 120. A vertical alignment film (not shown) is provided on the surfaces of the substrates 110a and 110b in contact with the liquid crystal layer 120. When no voltage is applied, the liquid crystal molecules of the liquid crystal layer 120 are substantially perpendicular to the surface of the vertical alignment film. Oriented. The liquid crystal layer 120 includes a nematic liquid crystal material having negative dielectric anisotropy, and further includes a chiral agent as necessary.

  The liquid crystal display device 100 includes a pixel electrode 111 formed on the transparent substrate 110a and a counter electrode 131 formed on the transparent substrate 110b, and a liquid crystal provided between the pixel electrode 111 and the counter electrode 131. Layer 120 defines the pixel. Here, both the pixel electrode 111 and the counter electrode 131 are formed of a transparent conductive layer (for example, an ITO layer). Typically, on the liquid crystal layer 120 side of the transparent substrate 110b, a color filter 130 provided corresponding to the pixel (a plurality of color filters may be collectively referred to as the color filter layer 130), and A black matrix (light-shielding layer) 132 provided between adjacent color filters 130 is formed, and a counter electrode 131 is formed thereon. The color filter layer 130 is formed on the counter electrode 131 (the liquid crystal layer 120 side). Alternatively, the black matrix 132 may be formed.

  The liquid crystal display device 100 has a light shielding region around each pixel, and has a groove structure 115a on the transparent substrate 110a in the light shielding region. The groove structure 115a is formed on the interlayer insulating film 115 formed so as to cover circuit elements (including not only active elements such as switching elements but also wires and electrodes: not shown here) formed on the transparent substrate 110a. Is formed. For example, as will be described later, when an interlayer insulating film is provided in a transmissive liquid crystal display device having a TFT as a circuit element, the pixel electrode can be partially overlapped with the gate signal wiring and / or the source signal wiring. , The aperture ratio can be improved.

  Here, the light shielding region is shielded by, for example, a TFT, a gate signal wiring, a source signal wiring, or a black matrix formed on the transparent substrate 110b, which is formed in the peripheral region of the pixel electrode 111 on the transparent substrate 110a. This area does not contribute to display. Therefore, the groove structure 115a arranged in the light shielding region does not adversely affect the display.

  The groove structure 115a illustrated here is provided as a single continuous groove so as to surround the pixel, but is not limited thereto, and may be divided into a plurality of grooves. Since the groove structure 115a acts so as to define a boundary formed in the vicinity of the extension of the pixels in the liquid crystal domain, it is preferable that the groove structure 115a has a certain length. For example, when the groove structure is composed of a plurality of grooves, the length of each groove is preferably longer than the length between adjacent grooves.

  The pixel electrode 111 illustrated here has two openings 114 and four notches 113 formed at predetermined positions. When a predetermined voltage is applied to the liquid crystal layer, two liquid crystal domains each having an axially symmetric orientation are formed, and the central axis of each of the liquid crystal domains is formed in or near the opening 114. The As will be described later, the opening 114 provided in the pixel electrode 111 acts to fix the position of the central axis of the axially symmetric orientation. The notch 113 is provided in the vicinity of the boundary of the axially symmetric alignment domain, and defines the direction in which the liquid crystal molecules are tilted by the electric field, and acts to form the axially symmetric alignment domain. An oblique electric field is formed around the opening 114 and the notch 113 by a voltage applied between the pixel electrode 111 and the counter electrode 113, and a direction in which liquid crystal molecules are inclined is defined by the oblique electric field. As a result, it operates as described above. Here, the notch 113 is centered on an opening 114 (here, the opening on the right side in FIG. 1) corresponding to the central axis of the liquid crystal domain formed in the pixel (here, the entire transmission region). It includes four notches 113 arranged symmetrically with respect to a point.

  By providing such a notch 113, the direction in which the liquid crystal molecules fall when a voltage is applied is defined, and two liquid crystal domains are formed. In FIG. 1, the reason why the notch is not provided on the left side of the pixel electrode 111 is that the notch provided at the right end of the pixel electrode (not shown) located on the left side of the illustrated pixel electrode 111 has the same effect. Therefore, a notch that reduces the effective aperture ratio of the pixel is omitted at the left end of the pixel electrode 111. Here, since the alignment regulating force by the groove structure 115a described above can also be obtained, a stable liquid crystal domain can be formed as in the case where the notch is provided without providing the notch on the left end of the pixel electrode 111. In addition, the effect of improving the effective aperture ratio can be obtained.

  Here, four cutout portions 113 are formed, but at least one cutout portion may be provided between adjacent liquid crystal domains. For example, here, a long and thin cutout portion is provided at the center of the pixel. Others may be omitted.

  The shape of the opening 114 provided to fix the central axis of the axially symmetric orientation domain is preferably circular as illustrated, but is not limited thereto. However, in order to exert substantially the same orientation regulating force in all directions, the polygon is preferably a quadrilateral or more, and is preferably a regular polygon. The shape of the notch 113 acting so as to define the direction in which the liquid crystal molecules in the axially symmetric alignment domain are tilted by the electric field is set so as to exert an alignment regulating force substantially equal to the adjacent axially symmetric alignment. A quadrangle is preferred.

  If a support 133 for defining the thickness dt (also referred to as a cell gap) of the liquid crystal layer 120 is formed in a light shielding region (here, a region defined by the black matrix 132), display quality is not deteriorated. Therefore, it is preferable. The support 133 may be formed on either of the transparent substrates 110a and 110b, and is not limited to the case where the support 133 is provided on the bottom of the groove structure 115a provided in the light shielding region as illustrated. When the support 133 is formed on the bottom of the groove structure 115a, the depth of the groove structure 115a from the height of the support 133 (the thickness of the interlayer insulating film 115 in the portion where the groove structure 115a is formed). And the difference between the thickness of the interlayer insulating film 115 in other regions) and the thickness of the liquid crystal layer 120 are set. When the support body 133 is provided in a region where the groove structure 115 a is not formed, the height of the support body 133 is set to be the thickness of the liquid crystal layer 120. The support 133 can be formed by a photolithography process using a photosensitive resin, for example.

  In this liquid crystal display device 100, when a predetermined voltage (a voltage equal to or higher than the threshold voltage) is applied to the pixel electrode 111 and the counter electrode 131, the respective central axes are stabilized in or near the two openings 114. Two axially symmetric orientations are formed, and a pair of notches provided at the center in the longitudinal direction of the pixel electrode 11 define the direction in which liquid crystal molecules in two adjacent liquid crystal domains are tilted by an electric field, and the groove structure 115a and The notch 113 provided in the corner portion of the pixel electrode 111 defines the direction in which the liquid crystal molecules near the extension of the pixel in the liquid crystal domain are tilted by the electric field. It is considered that the alignment regulating force by the groove structure 115a, the opening 114, and the notch 113 acts cooperatively to stabilize the alignment of the liquid crystal domain.

  Note that, on the liquid crystal layer 120 side of the transparent substrate 110a, for example, an active element such as a TFT and circuit elements (not shown) such as a gate signal wiring and a source signal wiring connected to the TFT are provided. In addition, the transparent substrate 110a, the circuit elements formed on the transparent substrate 110a, the pixel electrode 111, the interlayer insulating film 115, the support 133, the alignment film, and the like described above may be collectively referred to as an active matrix substrate. On the other hand, the transparent substrate 110b and the color filter layer 130, the black matrix 132, the counter electrode 131, the alignment film, and the like formed on the transparent substrate 110b may be collectively referred to as a counter substrate or a color filter substrate.

  Further, although omitted in the above description, the liquid crystal display device 100 further includes a pair of polarizing plates arranged so as to face each other through the transparent substrates 110a and 110b. The pair of polarizing plates are typically arranged so that the transmission axes are orthogonal to each other. Furthermore, as described later, a biaxial optically anisotropic medium layer and / or a uniaxial optically anisotropic medium layer may be provided.

  Next, an example of the structure of an active matrix substrate that is preferably used in the transmissive liquid crystal display device 100 will be described with reference to FIGS. 2A and 2B. 2A is a partially enlarged view of the active matrix substrate, and FIG. 2B is a cross-sectional view taken along line X-X ′ in FIG. 2A. The active matrix substrate shown in FIGS. 2A and 2B is different from the active matrix substrate shown in FIG. 1 in that the number of notches 113 is small, but other configurations may be the same.

  The active matrix substrate shown in FIGS. 2A and 2B has a transparent substrate 110a made of, for example, a glass substrate, and the gate signal lines 2 and the source signal lines 3 are provided on the transparent substrate 110a so as to be orthogonal to each other. . A TFT 4 is provided in the vicinity of the intersection of these signal wires 2 and 3, and the drain electrode 5 of the TFT 4 is connected to the pixel electrode 111.

  The active matrix substrate has an interlayer insulating film 115 that covers the gate signal line 2, the source signal line 3, and the TFT 4, and the trench structure 115 a is formed in the interlayer insulating film 115. Therefore, for example, when forming the interlayer insulating film 115 using the photosensitive resin film 115, the groove structure 115a can be formed by the same photolithography process as the process of forming the contact hole. It can be manufactured by a simple process.

  The pixel electrode 111 is a transparent electrode formed from a transparent conductive layer such as ITO, and is formed on the interlayer insulating film 115. A contact portion 111 a formed in the contact hole of the interlayer insulating film 115 is connected to the drain electrode 5. In the predetermined region of the pixel electrode 111, as described above, the notch 113 and the opening 114 are provided in order to control the orientation of the axially symmetric orientation domain. Here, an example in which the pixel electrode 111 is extended to the inclined side surface of the groove structure 115a formed in the interlayer insulating film 115 is shown, but the present invention is not limited to this, and the pixel electrode 111 is formed in the groove structure 115a. It is not necessary. However, for the reason described below, the pixel electrode 111 is preferably formed up to the side surface portion of the groove structure 115a, and preferably covers a part of the side surface of the groove structure 115a.

  If the pixel electrode 111 is not provided on the inclined side surface of the groove structure 115a, the alignment of liquid crystal molecules at the end of the pixel electrode 111 is likely to be disturbed, and when the entire groove structure 115a is covered. Since the equipotential lines are formed in parallel along the surface of the groove structure 115a, the wall surface effect (step difference effect) by the groove structure 115a may not be sufficiently exhibited. Therefore, the pixel electrode 111 is preferably extended so as to cover the side surface portion or a part of the groove structure 115a.

The pixel electrode 111 is superimposed on the gate signal line of the next stage through the gate insulating film 9. The TFT 4 has a structure in which a gate insulating film 9, a semiconductor layer 12, a channel protective layer 13, and an n ⁺ -Si layer 11 (source / drain electrodes) are stacked on the gate electrode 10 branched from the gate signal line 2. doing.

  Note that although a configuration example of a bottom-gate TFT is shown here, the present invention is not limited to this, and a top-gate TFT can also be used. In addition, a switching element (for example, MIM) other than the TFT can be used.

  In the liquid crystal display device 100, the notch 113 and the opening 114 are formed in the pixel electrode 111 provided on the interlayer insulating film 115 in which the groove structure 115a is formed, and the alignment regulating structure is provided on the counter substrate 110b side. Not. According to the present embodiment, there is an advantage that a stable axially symmetric alignment domain can be formed with such a simple configuration. However, the present invention is not limited to this. For example, an alignment regulating structure may be provided on the counter substrate 110b side as in the liquid crystal display device 100 'illustrated in FIG. 2C. By adopting such a configuration, the alignment of liquid crystal molecules can be further stabilized.

  The liquid crystal display device 100 ′ has substantially the same configuration as the liquid crystal display device 100 except that the counter electrode 131 has an opening 114 ′. Common reference numerals are used and description thereof is omitted here.

  The opening 114 ′ formed in the counter substrate 131 of the liquid crystal display device 100 ′ is provided at a position substantially overlapping the opening 114 formed in the pixel electrode 111 when viewed from the normal direction of the substrate. The plan view of the display device 100 ′ is substantially the same as FIG. The opening 114 ′ arranged in this way acts to fix and stabilize the central axis of the axially symmetric orientation together with the opening 114 formed in the pixel electrode 111. As a result, the orientation of the axially symmetric orientation domain is further stabilized.

  Note that it is preferable not to provide a structural alignment regulating structure such as a groove structure or a convex portion on the counter substrate 110b side. In order to form a groove structure or the like, unlike an opening or a notch formed in an electrode, the number of manufacturing steps increases, which is a factor in increasing costs, which is not preferable. Further, unlike the opening having the function of fixing the central axis, the notch 113 is provided so as to define the direction in which the liquid crystal molecules are tilted by the electric field in cooperation with the anchoring action of the side surface of the groove structure 115a. It is preferable to provide only on the same substrate 110a as the groove structure 115a.

(Transflective liquid crystal display device)
Next, the configuration of the transflective liquid crystal display device 200 according to the embodiment of the present invention will be described with reference to FIG.

  It is a figure which shows typically the structure of one pixel of the transmissive liquid crystal display device 200 of embodiment by this invention, (a) is a top view, (b) is 3B- in FIG. 3 (a). It is sectional drawing along line 3B '.

  The liquid crystal display device 200 includes a transparent substrate (for example, a glass substrate) 210a, a transparent substrate 210b provided to face the transparent substrate 210a, and a vertical alignment type liquid crystal layer provided between the transparent substrates 210a and 210b. 220. A vertical alignment film (not shown) is provided on the surfaces of both the substrates 210a and 210b in contact with the liquid crystal layer 220. When no voltage is applied, the liquid crystal molecules of the liquid crystal layer 220 are in contact with the surface of the vertical alignment film. Oriented substantially vertically. The liquid crystal layer 220 includes a nematic liquid crystal material having a negative dielectric anisotropy, and further includes a chiral agent as necessary.

  The liquid crystal display device 200 includes a pixel electrode 211 formed on the transparent substrate 210a and a counter electrode 231 formed on the transparent substrate 210b, and a liquid crystal provided between the pixel electrode 211 and the counter electrode 231. Layer 220 defines the pixel. Circuit elements such as TFTs are formed on the transparent substrate 210a as will be described later. The transparent substrate 210a and the components formed thereon may be collectively referred to as an active matrix substrate 210a.

  Further, typically, a color filter 230 (corresponding to a plurality of color filters may be collectively referred to as the color filter layer 230) provided corresponding to the pixel on the liquid crystal layer 220 side of the transparent substrate 210b. A black matrix (light shielding layer) 232 provided between adjacent color filters 230 is formed, and a counter electrode 231 is formed thereon, and the color filter layer 230 is formed on the counter electrode 131 (the liquid crystal layer 120 side). Alternatively, a black matrix 232 may be formed. The transparent substrate 210b and the components formed thereon may be collectively referred to as a counter substrate (color filter substrate) substrate 210b.

  The pixel electrode 211 is formed of a transparent electrode 211a formed from a transparent conductive layer (for example, an ITO layer) and a metal layer (for example, an Al layer, an alloy layer including Al, and a laminated film including any of these). A reflective electrode 211b. As a result, the pixel includes a transparent area A defined by the transparent electrode 211a and a reflective area B defined by the reflective electrode 211b. The transparent area A displays in the transmissive mode, and the reflective area B displays in the reflective mode.

  The liquid crystal display device 200 has a light shielding region around each pixel, and has a groove structure 215a on the transparent substrate 210a in the light shielding region. The groove structure 215a is formed on the interlayer insulating film 215 formed so as to cover circuit elements (including not only active elements such as switching elements but also wires and electrodes: not shown here) formed on the transparent substrate 210a. Is formed. For example, as will be described later, when an interlayer insulating film is provided in a liquid crystal display device having a TFT as a circuit element, the pixel electrode can be formed so as to partially overlap with the gate signal wiring and / or the source signal wiring. The aperture ratio of the region can be improved.

  Further, since the light shielding area around the pixel does not contribute to display, the groove structure 215a formed in the light shielding area does not adversely affect the display. The groove structure 215a illustrated here is provided as a single continuous groove so as to surround the pixel. However, the groove structure 215a is not limited to this and may be divided into a plurality of grooves. Since the groove structure 215a acts so as to define a boundary formed in the vicinity of the extension of the pixel in the liquid crystal domain, it preferably has a certain length. For example, when the groove structure 215a is constituted by a plurality of grooves, the length of each groove is preferably longer than the length between adjacent grooves.

  The groove structure 215a in the liquid crystal display device 200 is further disposed at the boundary between the transmission region A and the reflection region B. The groove structure 215a acts so as to define the alignment direction of the liquid crystal molecules at the boundary between the liquid crystal domain formed in the transmission region A and the liquid crystal domain formed in the reflection region B, which are adjacent to each other. The alignment regulating force by the groove structure 215a acts cooperatively with an oblique electric field by a pair of notches 213 provided at the boundary between the transmission region A and the reflection region B, and the liquid crystal molecules in the liquid crystal domain are axially symmetric. Orientate in a shape. Note that if the groove structure 215a is also disposed at the boundary between the transmissive region A and the reflective region B, the contrast ratio of the transmissive mode display may be reduced, and may be omitted. Here, the reason why the groove structure 215a is not provided at the boundary between the liquid crystal domains that are formed in the transmissive region A and adjacent to each other is to suppress a decrease in the contrast ratio of the display in the transmissive mode. A groove structure 215a may also be provided here. The groove structure 215a arranged in the pixel may be formed integrally with the groove structure 215a arranged around the pixel, or may be divided.

  The pixel electrode 211 exemplified here has three openings 214 and four notches 213 formed at predetermined positions. When a predetermined voltage is applied to the liquid crystal layer, three liquid crystal domains each having an axially symmetric orientation are formed, and the central axis of each of the liquid crystal domains is formed in or near the opening 214. The As will be described later, the opening 214 provided in the pixel electrode 211 acts to fix the position of the central axis of the axially symmetric alignment, and the notch 213 is a direction in which the liquid crystal molecules in the axially symmetric alignment domain are tilted by the electric field. Acts to prescribe. An oblique electric field is formed around the opening 214 and the notch 213 by a voltage applied between the pixel electrode 211 and the counter electrode 213, and a direction in which liquid crystal molecules are inclined is defined by the oblique electric field. As a result, it operates as described above. Further, here, the notch 213 is arranged symmetrically with respect to the opening 214 (here, the opening on the right side in FIG. 1) 214 corresponding to the central axis of the liquid crystal domain formed in the transmission region A of the pixel. 4 cutouts 213 formed therein. By providing such a notch 213, the direction in which the liquid crystal molecules fall when a voltage is applied is defined, and three liquid crystal domains are formed. The arrangement of the openings 214 and the notches 213 and their preferred shapes are the same as those of the transmissive liquid crystal display device 100 described above. Although FIG. 3 shows an example in which two liquid crystal domains are formed in the transmission region A and one liquid crystal domain is formed in the reflection region B, the present invention is not limited to this. In addition, it is preferable that each liquid crystal domain has a substantially square shape from the viewpoint of viewing angle characteristics and alignment stability.

  If the support 233 for defining the thickness dt (also referred to as a cell gap) of the liquid crystal layer 220 is formed in the light-shielding region (here, the region defined by the black matrix 232), the display quality is not deteriorated. Therefore, it is preferable. The support 233 may be formed on either of the transparent substrates 210a and 210b, and is not limited to the case where the support 233 is provided on the bottom of the groove structure 215a provided in the light shielding region as illustrated. When the support 233 is formed on the bottom of the groove structure 215a, the depth of the groove structure 215a from the height of the support 233 (the thickness of the interlayer insulating film 215 in the portion where the groove structure 215a is formed). And the difference between the thickness of the interlayer insulating film 215 in other regions) and the thickness of the liquid crystal layer 220 are set. In the case where the support 233 is provided in a region where the groove structure 215 a is not formed, the height of the support 233 is set to be the thickness of the liquid crystal layer 220.

  In this liquid crystal display device 200, when a predetermined voltage (a voltage equal to or higher than the threshold voltage) is applied to the pixel electrode 211 and the counter electrode 231, the respective central axes are stabilized in or near the three openings 214. Groove structure in which three axially symmetric orientations are formed, and the four notches 213 provided in the pixel electrode 211 define the direction in which the liquid crystal molecules in the three adjacent liquid crystal domains are tilted by an electric field, and are arranged around the pixel 215a stabilizes the boundary formed in the vicinity of the extension of the pixels in the liquid crystal domain. Further, the groove structure 215a disposed also at the boundary between the transmissive region A and the reflective region B stabilizes the boundary between the liquid crystal domain formed in the transmissive region A and the liquid crystal domain formed in the reflective region B.

  Next, a preferable configuration unique to the transflective liquid crystal display device 200 capable of performing both transmission mode display and reflection mode display will be described.

  In the transmission mode display, the light used for display passes through the liquid crystal layer 220 only once, whereas in the reflection mode display, the light used for display passes through the liquid crystal layer 220 twice. Therefore, as schematically shown in FIG. 3B, it is preferable to set the thickness dt of the liquid crystal layer 220 in the transmissive region A to about twice the thickness dr of the liquid crystal layer 220 in the reflective region B. By setting in this way, the retardation that the liquid crystal layer 220 gives to the light in both display modes can be made substantially equal. Although dt = 0.5dr is most preferable, good display can be realized in both display modes as long as it is within the range of 0.3dt <dr <0.7dt. Of course, dt = dr may be used depending on the application.

  In the liquid crystal display device 200, in order to make the thickness of the liquid crystal layer 220 in the reflective region B smaller than the thickness of the liquid crystal layer in the transmissive region A, the transparent dielectric layer 234 is provided only in the reflective region B of the glass substrate 210b. Yes. By adopting such a configuration, there is no need to provide a step using an insulating film or the like under the reflective electrode 211b, so that there is an advantage that the manufacturing of the active matrix substrate 210a can be simplified. Further, when the reflective electrode 211b is provided over the insulating film for providing a step for adjusting the thickness of the liquid crystal layer 220, light used for transmissive display is blocked by the reflective electrode that covers the inclined surface (tapered portion) of the insulating film. However, since the light reflected by the reflective electrode formed on the slope of the insulating film repeats internal reflection, there is a problem that it is not effectively used for reflective display. Occurrence of problems can be suppressed and light utilization efficiency can be improved.

  Furthermore, if the transparent dielectric layer 234 having a function of scattering light (diffuse reflection function) is used, a good white display close to paper white can be realized without providing the reflection electrode 211b with a diffuse reflection function. it can. Even if the transparent dielectric layer 234 is not provided with a light scattering ability, a white display close to paper white can be realized by providing an uneven shape on the surface of the reflective electrode 211b. The position of the central axis of the symmetric orientation may not be stable. On the other hand, if the transparent dielectric layer 234 having light scattering ability and the reflective electrode 211b having a flat surface are used, the position of the central axis can be more reliably stabilized by the opening 214 formed in the reflective electrode 211b. Benefits are gained. In addition, in order to provide a diffuse reflection function to the reflective electrode 211b, when forming unevenness on the surface, the uneven shape is preferably a continuous wave shape so that no interference color is generated, and the central axis of the axially symmetric orientation is It is preferable to set so that it can be stabilized.

  In the transmissive mode, light used for display passes through the color filter layer 230 only once, whereas in reflective mode display, light used for display passes through the color filter layer 230 twice. Therefore, when a color filter layer having the same optical density is used for the transmission region A and the reflection region B as the color filter layer 230, color purity and / or luminance in the reflection mode may be lowered. In order to suppress the occurrence of this problem, it is preferable to make the optical density of the color filter layer in the reflective region smaller than that in the transmissive region. The optical density here is a characteristic value characterizing the color filter layer, and the optical density can be reduced by reducing the thickness of the color filter layer. Alternatively, the optical density can be reduced by reducing the concentration of the added dye, for example, while maintaining the thickness of the color filter layer.

  Next, an example of the structure of an active matrix substrate that is preferably used in a transflective liquid crystal display device will be described with reference to FIGS. 4 is a partially enlarged view of the active matrix substrate, and FIG. 5 is a cross-sectional view of the liquid crystal display device, which corresponds to a cross-sectional view taken along line X-X ′ in FIG. 4. The active matrix substrate shown in FIGS. 4 and 5 has a configuration in which one liquid crystal domain is formed in the transmissive region A (that is, the number of openings 214 and notches 213 is small). Although different from the active matrix substrate shown in FIG. 3, other configurations may be the same, and common components are denoted by common reference numerals.

  The active matrix substrate shown in FIGS. 4 and 5 includes a transparent substrate 210a made of, for example, a glass substrate, and the gate signal line 2 and the source signal line 3 are provided on the transparent substrate 210a so as to be orthogonal to each other. . A TFT 4 is provided in the vicinity of the intersection of these signal lines 2 and 3, and the drain electrode 5 of the TFT 4 is connected to the pixel electrode 211.

  The pixel electrode 211 includes a transparent electrode 211a formed from a transparent conductive layer such as ITO, and a reflective electrode 211b formed from Al or the like. The transparent electrode 211a defines the transmission region A, and the reflective electrode 211b reflects. Region B is defined. Note that a transparent conductive layer may be formed over the reflective electrode 211b as necessary.

  The pixel electrode 211 is formed on the interlayer insulating film 215, and the pixel electrode 211 (transparent electrode 211 a) is connected to the drain electrode 5 at a contact portion 211 c formed in the contact hole 29 of the interlayer insulating film 215. The connection electrode 25 is connected. The reflective electrode 211b is connected to the transparent electrode 211a.

  As shown in FIG. 5, the pixel electrode 211 may also be extended on the slope of the groove structure 215a formed in the interlayer insulating film 215, or may extend to the slope of the groove structure 215a. It does not have to be installed.

  In a predetermined region of the pixel electrode 211, as described above, the notch 213 and the opening 214 are provided in order to control the orientation of the axially symmetric orientation domain. The connection electrode 25 constitutes an auxiliary capacitance with the auxiliary capacitance wiring (auxiliary capacitance electrode) 30 provided so as to face each other with the gate insulating film 9 interposed therebetween. For example, the auxiliary capacitance line is provided in parallel with the gate signal line 2 below the reflective electrode 211b. For example, the auxiliary capacitor wiring 30 is supplied with the same signal (common signal) as that of the counter electrode provided on the color filter side substrate. Here, the auxiliary capacitance line 30 is provided below the reflective electrode 211b. However, the auxiliary capacitance line 30 is provided at the boundary between the transmission region A and the reflection region B, and is arranged at the boundary between the transmission region A and the reflection region B. Light leakage from the vicinity of the groove structure 215a may be suppressed.

  The reflective electrode 211b of the transflective liquid crystal display device of this embodiment has an uneven surface, and has excellent diffuse reflection characteristics. The uneven shape on the surface of the reflective electrode 211 b reflects the uneven shape formed on the surface of the interlayer insulating film 215.

  In the interlayer insulating film 215, a groove structure 215a is formed, and further, a region having a substantially flat surface (sometimes referred to as “first region”) and a region having a concavo-convex shape (“first region”). 2 areas). A transparent electrode 211a is formed on the first region having a flat surface, and a reflective electrode 211b is formed on the second region having irregularities. The interlayer insulating film 215 including the groove structure 215a and the region 215c having an uneven shape on the surface can be formed from a single photosensitive resin film by a series of photolithography processes, as will be described later. It can be manufactured by a simpler process than before.

The pixel electrode 211 is superimposed on the gate signal line 2 in the next stage via the gate insulating film 9. The TFT 4 has a structure in which a gate insulating film 9, a semiconductor layer 12, a channel protective layer 13, and an n ⁺ -Si layer 11 (source / drain electrodes) are stacked on the gate electrode 10 branched from the gate signal line 2. doing.

  Note that although a configuration example of a bottom-gate TFT is shown here, the present invention is not limited to this, and a top-gate TFT can also be used. In addition, a switching element (for example, MIM) other than the TFT can be used.

  As described above, the liquid crystal display device 200 having the configuration shown in FIG. 3 is similar to the liquid crystal display device 100 in that the alignment regulating structure (notch formed in the pixel electrode 211) has an axially symmetric orientation only on one substrate. With a relatively simple configuration provided with the portion 213, the opening 214, and the groove structure 215a), the liquid crystal alignment can be sufficiently stabilized. Note that, in the transflective liquid crystal display device 200 as in the transmissive liquid crystal display device 100 ′ illustrated in FIG. 2C, the alignment can be further stabilized by providing the alignment regulating structure on the counter substrate side. However, for the reasons described above, it is preferable that the orientation regulating structure provided on the counter substrate is only an opening for fixing the central axis of the axially symmetric orientation.

  Furthermore, the liquid crystal display device 200 can improve display brightness and color purity in the transmissive mode and the reflective mode by configuring the transparent attractant layer 234 and / or the color filter layer 230 as described above.

  Next, an example of the overall arrangement of the groove structure 215a in the display area will be described with reference to FIG.

  An interlayer insulating film 215a is formed over almost the entire surface of the transparent substrate 210a. As described above, the interlayer insulating film 215 is formed so as to cover circuit elements (TFT, gate signal wiring, source signal wiring, etc.) formed on the transparent substrate 210a, and is formed on the interlayer insulating film 215. The pixel electrode 211 and the drain electrode of the TFT are formed on almost the entire surface except for a contact hole for electrically connecting the pixel electrode 211 to the TFT drain electrode. The groove structure 215a is disposed at least around the pixel electrodes 211 arranged in a matrix, and here, the grooves intersecting each other (one is disposed in parallel with the source signal wiring and the other is disposed in parallel with the gate signal wiring). ) Is integrally formed with a grid-like groove structure 215a. Although not shown in FIG. 6, as described above, the groove structure 215a may also be disposed at the boundary between the transparent electrode 211a and the reflective electrode 211b. When the groove structure 215a is arranged in the pixel as described above, it is preferable to arrange the groove structure 215a on a metal wiring such as an auxiliary capacitance wiring in order to suppress light leakage from the vicinity of the groove structure 215a.

  The thickness of the interlayer insulating film 215 is preferably 2.0 μm or more and 3.5 μm or less, and the depth is preferably 0.5 μm or more in order to obtain a sufficient alignment regulating force of the groove structure 215a. . Further, if the thickness of the interlayer insulating film 215 on the source signal wiring and the gate signal wiring is 2.0 μm or more, even if the pixel electrode 211 extends on the inclined side surface of the trench structure 215a, This is preferable because the parasitic capacitance formed between the pixel electrode and the pixel electrode can be sufficiently reduced and does not adversely affect the display. In addition, the angle of the inclined side surface of the groove structure 215a (angle with respect to the substrate surface) is preferably 5 ° or more and 70 ° or less, and within this angle range, a vertical alignment film can be stably formed on the surface. In addition, the liquid crystal molecules can be effectively tilted and aligned when a voltage is applied.

  Next, a method for forming the interlayer insulating film 215 having the groove structure 215a will be described in detail with reference to FIG. In FIG. 7, the transparent substrate 210a and circuit elements such as TFTs and signal wirings formed thereon are collectively referred to as “circuit substrate 210A”.

  First, as shown in FIG. 7A, a circuit board 210A on which predetermined circuit elements such as TFTs are formed is prepared, and a positive photosensitive resin film (for example, Tokyo Ohka Co., Ltd.) is provided so as to cover the circuit elements. Manufactured, OFPR-800). The thickness of the photosensitive resin film is, for example, 4.5 μm.

  Next, as shown in FIG. 7B, the photosensitive resin film is exposed. At this time, predetermined regions having different exposure amounts are formed. That is, for each region to be a trench structure 215a (for example, a region shielded from light by a source signal wiring or a gate signal wiring), a region for forming unevenness on a surface (a region for forming a reflective electrode), and a region for forming a contact hole Change the exposure amount.

Specifically, the light shielding portion 52a is provided at a position corresponding to the convex portion (the convex portion of the concavo-convex surface) formed in the reflection region and at a position corresponding to the flat portion formed in the transmission region, and the groove structure 215a The photosensitive resin film 215 is exposed through the photomask 52 in which the corresponding position and the other region including the concave portion formed in the reflection region are the light transmitting portions 52b. The shape of the light-shielding part 52a corresponding to the convex part formed in the reflection region is, for example, a circular shape or a polygonal shape, and is randomly arranged with a predetermined center interval (5 to 30 μm) and a predetermined density. The arrangement of the convex portions may be random as long as no interference color is generated. As the light source, for example, an ultrahigh pressure mercury lamp (for example, illuminance of i-line: 20 to 50 mW) is used, and exposure is performed uniformly (irradiation time: 1 to 4 seconds). For example, the exposure amount is preferably about ²⁰ to 100 mJ / cm ² . In addition, it is preferable that the exposure amount at the position where the groove structure 215a is formed differs from the exposure amount at the position corresponding to the concave portion formed in the reflection region by adjusting the transmittance of the transmission part 52b. For example, the exposure amount at the position corresponding to the concave portion of the reflection region is set to a relatively low exposure amount of about 50 mJ / cm ^{2 in} terms of i-line, and the exposure amount at the position where the groove structure is formed is set to about 100 mJ / cm ² or more. Accordingly, it is possible to form a groove structure deeper than the concave portion formed in the reflective region.

Next, as shown in FIG. 7C, uniform exposure is performed using a photomask 62 having a light transmitting portion 62b corresponding to the contact hole portion and the other being a light shielding portion 62a (irradiation time: 10 to 10). 15 seconds). The amount of exposure is preferably about 200 to 500 mJ / cm ² , for example.

  Next, as shown in FIG. 7D, for example, development processing is performed under predetermined conditions using a TMAH (tetramethylammonium hydroxide) developer. For example, the resin film in the high exposure region is completely removed (contact holes are formed), and about 90% of the resin film in the unexposed region remains (flat portions and convex portions are formed), and the low exposure region About 40% of the resin film remains (the groove structure 215a and the recess formed in the reflective region are formed).

  Further, as shown in FIG. 7E, drying and baking are performed as necessary. Firing is performed at 200 ° C., for example. By performing the baking, a smooth uneven shape 215c is obtained due to a thermal sag phenomenon or the like of the resin in the reflective region 215c 'formed with a plurality of fine protrusions. By making the surface of the reflective electrode 211b smooth and uneven, it is possible to obtain good diffuse reflection characteristics in which the generation of interference colors is suppressed.

  In this way, a continuous batch exposure process is performed on the photosensitive resin film 215, and a subsequent development process is performed, so that the groove structure 215a and the interlayer 215c having the fine unevenness and the contact hole 29 are provided. An insulating film 215 is obtained.

  In the above exposure process, the method of forming regions with different exposure amounts by adjusting the irradiation time for each region using a photomask having a light transmitting portion and a light shielding portion has been described. An interlayer insulating film having a surface whose shape continuously changes can also be formed by performing exposure using a grayscale mask having a changing shading pattern.

  Further, in the exposure process, a third photomask having only a region where the groove structure is to be formed as a light shielding portion is used, and the exposure for forming the groove structure is continuously performed before the exposure process for forming the contact hole. It is also possible to do this.

  Next, as shown in FIG. 7F, a pixel electrode 211 is formed on the interlayer insulating film 215 obtained through the above-described steps. For example, the transparent electrode 211a is obtained by depositing and patterning a transparent conductive film (for example, an ITO film) to a predetermined film thickness (for example, 100 nm) by a sputtering method. The reflective electrode 211b is formed by depositing a reflective electrode film (for example, an Al thin film) to a predetermined film thickness (for example, 180 nm) by sputtering and patterning. When forming each electrode 211a and 211b, an opening part and / or a notch part are formed.

  According to the present embodiment, the groove structure 215a and the fine uneven shape of the reflective electrode portion are formed in the interlayer insulating film layer 215a, and the pixel electrode is formed on the upper layer, so that the pixel of the groove structure 215a is particularly formed. It is possible to dispose the pixel electrode also on the inclined side surface.

  In addition, you may form a transparent electrode film on the reflective electrode 211b as needed. By forming a transparent conductive film over the reflective electrode 211b, it is possible to reduce a difference in potential difference (electrode potential difference) between the reflective region and the transmissive region. The material of the transparent electrode film formed on the reflective electrode 211b is preferably the same material as the transparent electrode 211a.

  As described above, according to the manufacturing method of the present embodiment, the uneven structure for expressing the diffuse reflection characteristics and the groove structure as the orientation control structure can be obtained by simply performing the photolithography process on the single photosensitive resin film. A body can be formed, and cost reduction can be effectively performed.

  Hereinafter, after forming a vertical alignment film on a counter substrate (CF substrate) facing the active matrix substrate obtained as described above under a predetermined condition, these are bonded to each other through a seal resin, and the gap is formed in the gap. By enclosing a liquid crystal material having a negative dielectric anisotropy, the liquid crystal display device of this embodiment can be obtained. Since these steps are performed by a known method, description thereof is omitted.

  Although an example of a method for manufacturing a transflective liquid crystal display device has been described here, a groove structure and a contact hole, which are one of the alignment regulation structures of the liquid crystal domain, are collectively used when forming an interlayer insulating film layer. The technology that is manufactured in a continuous process can also be applied to transmissive liquid crystal display devices and reflective liquid crystal display devices. Of course, this is a simpler process than conventional methods, and has the effect of reducing costs and shortening the tact time during production. Play.

〔Operating principle〕
The reason why the liquid crystal display device according to the embodiment of the present invention having the vertical alignment type liquid crystal layer has excellent wide viewing angle characteristics will be described with reference to FIG.

  FIG. 8 is a diagram for explaining the action of the alignment regulating force due to the groove structure 16a formed in the interlayer insulating film 16 and the opening 15 provided in the pixel electrode 6, and FIG. (B) schematically shows the alignment state of liquid crystal molecules when a voltage is applied. The state shown in FIG. 8B is a state where a halftone is displayed.

  The liquid crystal display device shown in FIG. 8 has, on the transparent substrate 1, an interlayer insulating film 16 having a groove structure 16a, a pixel electrode 6 having an opening 15, and an alignment film 22 in this order. Circuit elements (not shown) such as switching elements are formed on the transparent substrate 1. On the other transparent substrate 17, the color filter layer 18, the counter electrode 19, and the alignment film 32 are formed in this order. The liquid crystal layer 20 provided between the two substrates includes liquid crystal molecules 21 having negative dielectric anisotropy.

  As shown in FIG. 8A, when no voltage is applied, the liquid crystal molecules 21 are aligned substantially perpendicular to the substrate surface by the alignment regulating force of the vertical alignment films 22 and 32. Although omitted in FIG. 8A for simplicity, liquid crystal molecules in the vicinity of the groove structure 16a are inclined toward the center line of the groove structure 16a due to the alignment regulating force due to the inclined side surface of the groove structure 16a. Oriented. Since the vertical alignment film 12 is formed so as to cover the groove structure 16a, the liquid crystal molecules 21 are subjected to a regulating force that aligns perpendicularly to the inclined side surface of the groove structure 16a. Further, the liquid crystal molecules 21 in the vicinity of the opening 15 are also subjected to the alignment regulating force due to the step formed corresponding to the opening 15 (step formed on the surface of the alignment film 12), and toward the center of the opening 15. Slightly inclined.

  On the other hand, when a voltage is applied, as shown in FIG. 8B, the liquid crystal molecules 21 having a negative dielectric anisotropy tend to have the molecular long axis perpendicular to the lines of electric force. The direction in which the liquid crystal molecules 21 are tilted is defined by the formed oblique electric field. Therefore, for example, it is oriented in an axially symmetrical manner with the opening 15 as the center. In this axially symmetric alignment domain, the liquid crystal directors are aligned in all directions (directions in the substrate plane), so that viewing angle characteristics are excellent. On the other hand, the liquid crystal molecules 21 on and in the vicinity of the groove structure 16a are inclined toward the liquid crystal molecules 21 aligned perpendicular to the substrate surface on the center line of the groove structure 16a. The tilt direction of the liquid crystal molecules 21 shown in FIG. 8B coincides with the tilt direction defined by the alignment regulating force due to the step corresponding to the tilted side surface and the opening 15 of the groove structure 16a when no voltage is applied. .

  Here, the action of the oblique electric field formed around the opening 15 has been described, but an oblique electric field is similarly formed in the vicinity of the notch formed at the edge of the pixel electrode 6, and the liquid crystal molecules 21. The direction in which is tilted by the electric field is defined.

  Next, a more specific configuration example of the liquid crystal display device according to the embodiment of the present invention will be described with reference to FIG.

  The liquid crystal display device shown in FIG. 9 includes a backlight, a transflective liquid crystal panel 50, a pair of polarizing plates 40 and 43 provided so as to face each other through the transflective liquid crystal panel 50, and the polarizing plate 40. Quarter wave plates 41 and 44 provided between the liquid crystal panel 50 and the liquid crystal panel 50, and the optical anisotropy provided between the quarter wave plates 41 and 44 and the liquid crystal panel 50 is negative. The phase difference plates 42 and 45 are included. The liquid crystal panel 50 includes a vertical alignment type liquid crystal layer 20 between a transparent substrate (active matrix substrate) 1 and a transparent substrate (counter substrate) 17. Here, a liquid crystal panel 50 having the same configuration as that of the liquid crystal display device 200 shown in FIG. 3 is used.

  The display operation of the liquid crystal display device shown in FIG. 9 will be briefly described below.

  For the reflection mode display, incident light from above passes through the polarizing plate 43 and becomes linearly polarized light. This linearly polarized light becomes circularly polarized light when it enters the quarter wavelength plate 44 so that the transmission axis of the polarizing plate 43 and the slow axis of the quarter wavelength plate 44 are 45 °, and is formed on the substrate 17. It passes through a color filter layer (not shown). Here, a phase difference plate 45 that does not give a phase difference to light incident from the normal direction is used.

  When no voltage is applied, since the liquid crystal molecules in the liquid crystal layer 20 are aligned substantially perpendicular to the substrate surface, the incident light is transmitted with a phase difference of approximately 0 and is reflected by the reflective electrode formed on the lower substrate 1. The The reflected circularly polarized light passes through the liquid crystal layer 20 again, passes through the color filter layer, passes again through the retardation plate 45 having negative optical anisotropy as circularly polarized light, passes through the quarter-wave plate 44, and then first. The light is converted into linearly polarized light having a polarization direction orthogonal to the polarization direction when passing through the polarizing plate 43 and reaches the polarizing plate 43, so that light cannot pass through the polarizing plate 43 and is displayed in black.

  On the other hand, when a voltage is applied, the liquid crystal molecules in the liquid crystal layer 20 are inclined in the horizontal direction from the direction perpendicular to the substrate surface, so that the incident circularly polarized light becomes elliptically polarized light due to the birefringence of the liquid crystal layer 20 and is formed on the lower substrate 1. Reflected by the reflected electrode. The reflected light is further broken in the polarization state by the liquid crystal layer 20, passes through the liquid crystal layer 20 again, passes through the color filter layer, passes through the retardation plate 45 having negative optical anisotropy again, and becomes 1/4. Since the light is incident on the wave plate 44 as elliptically polarized light, all the light does not become linearly polarized light orthogonal to the polarization direction at the time of incidence when reaching the polarizing plate 43, and part of the light is transmitted through the polarizing plate 43. In particular, by adjusting the applied voltage, the direction in which the liquid crystal molecules are tilted can be controlled, and the amount of light that can be reflected by the polarizing plate 43 is modulated, thereby enabling gradation display.

  Regarding the display of the transmission mode, the two upper and lower polarizing plates 43 and 40 are arranged so that their transmission axes are orthogonal to each other, and the light emitted from the light source becomes linearly polarized light by the polarizing plate 40, This linearly polarized light becomes circularly polarized light and has a negative optical anisotropy when incident on the ¼ wavelength plate 41 so that the slow axis between the transmission axis of the polarizing plate 40 and the ¼ wavelength plate 41 is 45 °. The light enters the transmission region A of the lower substrate 1 through the phase difference plate 42. Here, a phase difference plate 42 that does not give a phase difference to light incident from the normal direction is used.

  When no voltage is applied, the liquid crystal molecules in the liquid crystal layer 20 are aligned substantially perpendicular to the substrate surface, so that incident light is transmitted with a phase difference of approximately 0 and is incident on the lower substrate 1 in a circularly polarized state. In the state of circular polarization, the light passes through the liquid crystal layer 20 and the upper substrate 17 and passes through the retardation plate 45 having the negative optical anisotropy to reach the quarter-wave plate 44. Here, the slow axis of the lower ¼ wavelength plate 41 and the upper ¼ wavelength plate 44 intersect each other by 90 °, so that the upper ¼ wavelength plate 44 is separated by the polarizing plate 40. The linearly polarized light is orthogonal to the linearly polarized light, and is absorbed by the polarizing plate 43 to display black.

  On the other hand, when a voltage is applied, since the liquid crystal molecules 21 in the liquid crystal layer 20 are inclined in the horizontal direction from the direction perpendicular to the substrate surface, the circularly polarized light incident on the liquid crystal display device becomes elliptically polarized light due to the birefringence of the liquid crystal layer 20, and the upper side. Since the CF substrate 16 and the retardation plate 45 and the quarter wavelength plate 44 having negative optical anisotropy on the upper side reach the polarizing plate 43 as elliptically polarized light, the linearly polarized light orthogonal to the polarization component at the time of incidence is not obtained. Instead, light passes through the polarizing plate 43. In particular, by adjusting the applied voltage, the direction in which the liquid crystal molecules are tilted can be controlled, and the amount of light that can be reflected by the polarizing plate 43 is modulated, thereby enabling gradation display.

  A retardation plate having a negative optical anisotropy minimizes the amount of change in retardation when the viewing angle is changed in a vertically aligned state of liquid crystal molecules, and suppresses black floating on the wide viewing angle side. Further, a biaxial retardation plate in which a retardation plate having negative optical anisotropy and a quarter wavelength plate are integrated may be used.

  When a normally black mode in which black display is performed when no voltage is applied and white display is performed when a voltage is applied as in the present invention is performed in an axially symmetric alignment domain, a pair of quarter wavelengths are formed above and below the liquid crystal display device (panel). By providing the plate, it is possible to improve the brightness by eliminating the extinction pattern caused by the polarizing plate. In addition, when the normally black mode is performed in the axially symmetric alignment domain by arranging the transmission axes of the upper and lower polarizing plates orthogonally to each other, in principle, the same degree as that of a pair of polarizing plates arranged in crossed Nicols. Since a black display can be realized, an extremely high contrast ratio can be realized, and a wide viewing angle characteristic led to an omnidirectional orientation can be achieved.

  Below, the specific example regarding this invention is described and demonstrated.

(Example)
A liquid crystal display device was configured by arranging an active matrix substrate having the configuration shown in FIG. 6 and a color filter substrate in which a color filter layer, a transparent dielectric layer 234 layer, and a counter electrode were laminated on the opposite side.

  In the manufacturing process of the active matrix substrate of this example, the interlayer insulating film having the groove structure was formed by the above-described process under the following exposure conditions.

The first exposure step for forming the concavo-convex shape and the groove structure on the positive photosensitive resin film is performed using the first photomask 52 under the low exposure amount condition (80 mJ / cm ² ), and the contact hole The second exposure step for forming the film was performed using the second photomask 62 under a high exposure amount condition (350 mJ / cm ² ). Then, the active matrix substrate of the present example was obtained by executing the series of steps described above.

  On the other hand, in the color filter substrate, a step of the transparent dielectric layer is arranged in the reflection region, and a support (dielectric) provided to define the liquid crystal layer thickness in the light shielding layer portion outside the display pixel is formed.

  After forming a vertical alignment film on the active matrix substrate and the color filter substrate under predetermined conditions (no rubbing treatment), the substrates are bonded together with a seal resin, and a liquid crystal material having a negative dielectric anisotropy ( Refractive index anisotropy Δn; 0.1 and dielectric anisotropy Δε; −4.5) were injected and sealed to prepare a liquid crystal display panel. In this example, the liquid crystal layer thickness dt in the transmissive region was 4 μm, and the liquid crystal layer thickness dr in the reflective region was 2.1 μm.

  Subsequently, an optical film was disposed on both sides of the liquid crystal display panel for the following, to obtain a liquid crystal display device.

  The configuration of the liquid crystal display device of the present embodiment includes a polarizing plate (observation side), a quarter-wave plate (retardation plate 1), and a retardation plate with negative optical anisotropy (retardation plate 2) in this order from the viewer side. (NR plate)), liquid crystal layer (upper side: color filter substrate, lower side: active matrix substrate), retardation plate with negative optical anisotropy (retardation plate 3 (NR plate)), quarter wavelength plate ( The phase difference plate 4) and the polarizing plate (backlight side) were laminated. In addition, in the upper and lower quarter-wave plates (the phase difference plate 1 and the phase difference plate 4) of the liquid crystal layer, their slow axes were orthogonal to each other, and each phase difference was set to 140 nm. Retardation plates having negative optical anisotropy (retardation plate 2 and retardation plate 3) each have a retardation of 135 nm. The two polarizing plates (observation side and backlight side) were arranged with their absorption axes orthogonal to each other.

  A drive signal was applied to the obtained liquid crystal display device (4 V was applied to the liquid crystal layer) to evaluate display characteristics.

  A viewing angle-contrast characteristic result in the transmissive display is shown in FIG. The viewing angle characteristics in the transmissive display are almost omnidirectional and symmetric, the CR> 10 region is as good as ± 80 °, and the transmissive contrast is as high as 300: 1 or more in the front.

  On the other hand, the characteristics of the reflective display are evaluated by a spectrocolorimeter (CM 2002 manufactured by Minolta Co., Ltd.), about 8.6% (converted value of aperture ratio 100%) based on the standard diffusion plate, and the contrast value of the reflective display is 21. Therefore, the contrast was high as compared with the conventional liquid crystal display device.

(Comparative example)
An ECB mode homogeneous alignment liquid crystal display panel was manufactured using a liquid crystal panel having the same configuration as the liquid crystal panel of the example. In the liquid crystal panel of the comparative example, the groove structure and the opening or notch of the pixel electrode are not formed. In addition, the liquid crystal panel of the comparative example uses a horizontal alignment film instead of the vertical alignment film of the liquid crystal panel of the embodiment, and the liquid crystal layer has a liquid crystal material (Δn; 0.07, Δε having positive dielectric anisotropy). 8.5) was injected to form a homogeneously oriented liquid crystal layer. The liquid crystal layer thickness dt in the transmissive region was 4.3 μm, and the liquid crystal layer thickness dr in the reflective region was 2.3 μm.

  A liquid crystal display device of a comparative example was obtained by arranging optical films formed of a plurality of optical layers including retardation plates such as polarizing plates and quarter-wave plates on both surfaces of the liquid crystal display panel.

  A drive signal was applied to the liquid crystal display device of this comparative example (4 V was applied to the liquid crystal layer), and display characteristics were evaluated according to the same evaluation method as in the example.

  The viewing angle characteristics in transmissive display were ± 30 ° in the region of CR> 10, and the gradation inversion was significant. The transmission contrast was 140: 1. On the other hand, the characteristics of the reflective display are about 9.3% (value converted to 100% aperture ratio) with respect to the standard diffusion plate, the contrast value of the reflective display is 8, and the display image is compared with the embodiment in the vertical mode. White contrast was low and blurred.

  As described above, the liquid crystal display device according to the embodiment of the present invention has a transmissive and reflective display by applying the vertical alignment mode to the transmissive display and the reflective display as compared with the conventional homogeneous liquid crystal display device and the conventionally known technology. A good contrast ratio can be obtained in both reflection displays.

  Furthermore, in the embodiment of the present invention, the restriction structure (groove structure and opening or notch) of the liquid crystal domain alignment is disposed only on one side substrate (illustratively, active matrix substrate), and the groove structure is disposed between Since the insulating film layer can be continuously formed in a batch with the formation of the fine irregularities of the reflecting portion and the contact hole forming step, the manufacturing process can be simplified. Further, the direction in which the liquid crystal molecules fall when a voltage is applied in the rubbing-less process can be regulated by the alignment regulating force of the groove structure, the opening, or the notch. In addition, as exemplified in the embodiment of the present invention, by providing a liquid crystal domain alignment regulating structure, a plurality of liquid crystal domains that exhibit axial symmetry when a voltage is applied are formed for each pixel. Angular characteristics can be realized.

  As described above, the liquid crystal display device according to the present invention can realize a liquid crystal display device with excellent display quality with a relatively simple configuration. The present invention is suitably applied to a transmissive liquid crystal display device and a transflective (transmission / reflection) liquid crystal display device. In particular, the transflective liquid crystal display device is suitably used as a display device for mobile devices such as mobile phones.

It is a figure which shows typically the structure of one pixel of the transmissive liquid crystal display device 100 of embodiment by this invention, (a) is a top view, (b) is 1B- in FIG. 1 (a). It is sectional drawing along a 1B 'line. It is a top view which shows typically the structure of the active matrix substrate of the other transmissive liquid crystal display device of embodiment by this invention. It is sectional drawing which shows typically the structure of the active matrix substrate shown to FIG. 2A. It is sectional drawing which shows typically the structure of the other transmissive liquid crystal display device of embodiment by this invention. It is a figure which shows typically the structure of one pixel of the transflective liquid crystal display device 200 of embodiment by this invention, (a) is a top view, (b) is 3B- in FIG. 3 (a). It is sectional drawing along line 3B '. It is a top view which shows typically the structure of the active matrix substrate of the transflective liquid crystal display device of embodiment by this invention. FIG. 5 is a cross-sectional view schematically illustrating a configuration of a liquid crystal display device including the active matrix substrate illustrated in FIG. 4. It is a perspective view which shows typically the example of the whole arrangement | positioning in the display area of the groove structure in the transflective liquid crystal display device of embodiment by this invention. (A) to (f) are schematic views for explaining a method of manufacturing an active matrix substrate. It is the schematic explaining the operation | movement principle of the liquid crystal display device of embodiment by this invention, (a) shows the time at the time of no voltage application, and (b) at the time of voltage application, respectively. It is a schematic diagram which shows an example of a structure of the liquid crystal display device of embodiment by this invention. It is a figure which shows the viewing angle-contrast ratio characteristic of the liquid crystal display device of the Example by this invention.

Explanation of symbols

1 TFT (active matrix) substrate 2 Gate signal line 3 Source signal line 4 TFT
5 Drain electrode 6 Pixel electrode 7 Transparent electrode 8 Reflective electrode 9 Gate insulating film 10 Gate electrode 11 Source / drain electrode (n ⁺ -Si layer)
12 Semiconductor Layer 13 Channel Protection Layer 15 Opening 16 Interlayer Insulating Film 16a Groove Structure 17 Transparent Substrate (Counter (CF) Substrate)
18 Color filter layer 19 Counter electrode 20 Liquid crystal layer 21 Liquid crystal molecule 22, 32 Alignment film 29 Contact hole 50 Liquid crystal panel 40, 43 Polarizing plate 41, 44 1/4 wavelength plate 42, 45 Retardation plate with negative optical anisotropy (NR board)
100, 100 'Transmission type liquid crystal display device 110a Active matrix substrate 110b Counter substrate (color filter substrate)
111 pixel electrode 113 notch 114 opening 115 interlayer insulating film 115a groove structure 130 color filter layer 131 counter electrode 133 support 200 transflective liquid crystal display device 210a active matrix substrate 210b counter substrate (color filter substrate)
211 pixel electrode 211a transparent electrode 211b reflective electrode 211c contact hole 213 notch 214 opening 215 interlayer insulating film 215a groove structure 230 color filter layer 231 counter electrode 232 transparent dielectric layer (reflection part step)
233 Support

Claims (17)

A first substrate, a second substrate provided to face the first substrate, a liquid crystal layer provided between the first substrate and the second substrate, and formed on the first substrate. A first electrode; a second electrode formed on the second substrate; and an interlayer insulating film provided between the first electrode and the first substrate and having a trench structure.
Each includes a plurality of pixels including the first electrode, the second electrode, and the liquid crystal layer provided between the first electrode and the second electrode, and each of the periphery of the plurality of pixels. The liquid crystal display device has a light shielding region, and the groove structures are regularly arranged at least in the light shielding region.   2. The device according to claim 1, further comprising a plurality of switching elements electrically connected to the first electrode on the first substrate, wherein at least a part of the switching elements is covered with the interlayer insulating film. Liquid crystal display device.   3. The liquid crystal according to claim 1, wherein the liquid crystal layer is a vertical alignment type liquid crystal layer and forms at least one liquid crystal domain including liquid crystal molecules aligned in different directions when at least a predetermined voltage is applied. Display device.   4. The liquid crystal display device according to claim 1, wherein the first electrode and / or the second electrode has a plurality of openings or notches formed at predetermined positions. 5.   5. The liquid crystal display device according to claim 4, wherein the first electrode and / or the second electrode has at least two openings and at least one notch formed at predetermined positions. 6.   The liquid crystal display device according to claim 4, wherein the plurality of openings or notches are formed only in the first electrode.   The liquid crystal layer is a vertical alignment type liquid crystal layer, and forms at least two liquid crystal domains each exhibiting axial symmetry when at least a predetermined voltage is applied, and the axial symmetry of each of the at least two liquid crystal domains. 7. The liquid crystal display device according to claim 4, wherein the central axis is formed in or near the plurality of openings. The liquid crystal layer is a vertical alignment type liquid crystal layer, and forms at least two liquid crystal domains each exhibiting axially symmetric alignment when at least a predetermined voltage is applied,
The liquid crystal display device according to claim 1, wherein the groove structure is also disposed at a boundary between a pair of adjacent liquid crystal domains in the at least two liquid crystal domains.   9. The liquid crystal display device according to claim 8, wherein each of the plurality of pixels has a further light shielding region, and the groove structure disposed at the boundary is provided in the further light shielding region.   The liquid crystal display device according to claim 1, wherein the first electrode includes a transparent electrode that defines a transmissive region and a reflective electrode that defines a reflective region.   The liquid crystal display device according to claim 10, wherein the groove structure is also disposed at a boundary between the transmission region and the reflection region.   A pair of polarizing plates arranged to face each other with the first substrate and the second substrate interposed therebetween, and at least between the first substrate and / or the second substrate and the pair of polarizing plates The liquid crystal display device according to claim 1, further comprising one biaxial optically anisotropic medium layer.   It further has a pair of polarizing plates arranged so as to face each other with the first substrate and the second substrate interposed therebetween, and between the first substrate and / or the second substrate and the pair of polarizing plates. The liquid crystal display device according to claim 1, further comprising at least one uniaxial optically anisotropic medium layer. A first substrate, a second substrate provided to face the first substrate, a liquid crystal layer provided between the first substrate and the second substrate, and formed on the first substrate. A first electrode; a circuit element electrically connected to the first electrode; a second electrode formed on the second substrate; and a groove provided between the first electrode and the first substrate. A plurality of interlayer insulating films each having a structure, each including the first electrode, the second electrode, and the liquid crystal layer provided between the first electrode and the second electrode. A method of manufacturing a liquid crystal display device comprising pixels, having a light shielding region around the plurality of pixels, wherein the groove structure is regularly arranged at least in the light shielding region,
Forming a circuit element on the first substrate;
Forming a positive photosensitive resin film covering the circuit element;
A step of exposing the photosensitive resin film, the step of forming predetermined regions having different exposure amounts;
Developing the exposed photosensitive resin film to form the interlayer insulating film having a contact hole exposing a part of the circuit element and the groove structure;
Forming a first electrode on the interlayer insulating film;
A method for manufacturing a liquid crystal display device. The step of forming the interlayer insulating layer includes a step of forming a first region having a substantially flat surface and a second region having a concavo-convex shape on the surface,
The step of forming the first electrode includes a step of forming a transparent electrode on the interlayer insulating film in the first region and a step of forming a reflective electrode on the interlayer insulating film in the second region. The manufacturing method of the liquid crystal display device of Claim 14. The exposure step uses a first photomask to form the second region and the region to be the groove structure and other regions,
The method of manufacturing a liquid crystal display device according to claim 15, further comprising: a second exposure step of forming the first region and the contact hole using a second photomask in the other region.   The step of forming the first electrode and / or the second electrode includes a step of forming a conductive film and a step of patterning the conductive film. The step of patterning includes the first electrode and / or The method of manufacturing a liquid crystal display device according to claim 14, comprising a step of forming a plurality of openings or notches at predetermined positions of the second electrode.