JP5042467B2 - Liquid crystal display device and liquid crystal panel - Google Patents

Description

  The present invention relates to a liquid crystal display device and a liquid crystal panel, and more particularly to a technique for achieving both light shielding in the outer peripheral area of the liquid crystal panel and sufficient curing of the entire seal.

  Conventionally, developments for increasing the capacity, high-speed response, and mass production of liquid crystal display devices have progressed, and in recent years, manufacturing methods for realizing high definition and high display quality have been developed. .

  Some liquid crystal display devices use an active matrix type liquid crystal panel, and such a liquid crystal panel includes a TFT liquid crystal panel using a thin film transistor (TFT) as a switching element.

  In a liquid crystal panel, it is necessary to enclose a strict amount of liquid crystal between a pair of substrates. Examples of a method for filling a liquid crystal material in the liquid crystal panel include a dip method and a dispenser method. In these methods, after bonding a pair of substrates through a seal, liquid crystal is injected into the panel from the opening (sealing) of the seal using a capillary phenomenon and a pressure difference, and then the opening Is sealed.

  However, as the screen size increases, the tact time for filling the liquid crystal material has become a problem. Recently, as another method for filling the liquid crystal material in the panel, the single drop filling method (drop bonding method) ODF (also called One-Drop-Fill) method) has been developed.

  In the one-drop filling method, a seal pattern having no opening (sealing) is formed on one substrate. Then, a liquid crystal material is dropped on the substrate and into the seal pattern frame, and is superposed on the other substrate under reduced pressure, and then the seal is cured. According to the single drop filling method, there is an advantage that the screen size can be increased and the tact time for filling the liquid crystal material can be drastically reduced.

JP 2002-6328 A JP-A-10-268326

  By the way, in the conventional TFT liquid crystal panel, in order to prevent light such as backlight from leaking from the outer peripheral region (so-called frame portion) around the display region and from the gap between the pixels, these portions on the counter substrate are shielded from light. A layer (so-called black matrix) is provided. As this light shielding layer, a metal film having high light shielding properties (a chromium film or a chromium / chromium oxide two-layer film) or the like is generally used. Here, in the case of manufacturing a liquid crystal panel by a one-drop filling method, irradiation light is blocked by the light blocking layer in the seal curing step even if ultraviolet rays (UV) are irradiated from the counter substrate side. On the other hand, since a pixel electrode circuit or the like is provided in the outer peripheral region of the TFT substrate, the irradiation light is shielded by the circuit or the like even if ultraviolet rays are irradiated from the TFT substrate side.

  Thus, in the conventional TFT liquid crystal panel, it is considered difficult to uniformly irradiate the seal with ultraviolet rays, and in such a case, an insufficiently cured portion occurs in the seal. When such an insufficiently cured part comes into contact with the liquid crystal material, the resin component in the seal may be eluted and mixed into the liquid crystal. Such elution / mixing causes the alignment state of the liquid crystal to become unstable, which causes bleeding and unevenness, and as a result, may cause a display quality defect of the liquid crystal panel. In other words, the yield may decrease due to an increase in display defects in the display inspection.

  In order to solve such a problem, a method of removing a portion on the seal in the light shielding layer in the above-described conventional TFT liquid crystal panel and irradiating ultraviolet rays from the portion can be considered. However, since it is necessary to prevent the light emitted from the backlight from leaking from the outer peripheral region, it is necessary to dispose a light shielding layer on at least a part of the seal. It is thought that the shortage will occur.

  Patent Document 2 discloses a technique that can prevent insufficient curing of the seal even when the seal and the conductive pattern overlap. Specifically, a large number of light transmission gaps are provided in the portion of the conductive pattern that overlaps with the seal, and the light transmitted through this gap is irradiated directly or around to irradiate the seal, thereby curing the seal under the conductive pattern. If so.

  However, in the above technique of Patent Document 2, it is considered that sufficient exposure is difficult because the entire seal is not uniformly irradiated with light. In addition, it is considered that this technique needs to add a patterning process of a conductive pattern, and there is a problem at the time of alignment in the substrate bonding process, and it is considered difficult to achieve high contrast as display quality.

  The present invention has been made in view of this point, and an object of the present invention is to provide a liquid crystal panel and a liquid crystal display device that can achieve both light shielding of the outer peripheral region of the liquid crystal panel and sufficient curing of the entire seal.

In order to achieve the above object, according to the present invention, in a liquid crystal panel, a pixel electrode disposed in a display region and a peripheral region around the display region so as not to contact the pixel electrode are provided. A first dimming electrode extending to the vicinity of the outer edge of the region, and a light-transmissive second dimming disposed in the outer peripheral region so as to face the first dimming electrode. A second substrate including a photoelectrode and disposed opposite the first substrate; a first polarizing plate disposed on an outer surface of the first substrate; and disposed on an outer surface of the second substrate A second polarizing plate , a liquid crystal layer disposed between the first substrate and the second substrate so as to reach between the first dimming electrode and the second dimming electrode, Arranged between the first substrate and the second substrate so as to overlap the first dimming electrode and the second dimming electrode. A seal containing a photocurable component that seals the liquid crystal layer, and the first substrate has a circuit disposed in the outer peripheral region so as to overlap the first dimming electrode. And

In addition, in the liquid crystal display device including the liquid crystal panel and a driving device that drives and controls the liquid crystal panel, the liquid crystal display device includes the first dimming electrode and the first light source regardless of a display state of the display area. The voltage between the two dimming electrodes can be controlled in an analog manner, and the liquid crystal between the first dimming electrode and the second dimming electrode is put in a light-shielding state to display the image during image display. It is characterized in that the circuit can be visually inspected through the second dimming electrode while preventing light leakage in the outer peripheral region and displaying an image .

  According to such a configuration, the photocurable seal (agent) is disposed so as to overlap the light control electrode, and the second light control electrode is light transmissive, so that the seal is photocured (with thermosetting). It is possible to irradiate the seal with light through a light-transmitting dimming electrode. Thereby, the whole seal | sticker can fully be hardened | cured. For this reason, both the substrates can be firmly bonded, and components in the seal can be prevented from being eluted and mixed into the liquid crystal layer from the insufficiently cured portion of the seal. Therefore, a liquid crystal panel and a liquid crystal display device with high reliability and high display quality can be provided. In addition, since the voltage between the dimming electrodes can be controlled regardless of the display state of the display area, light leakage in the outer peripheral area can be prevented during image display by making the liquid crystal between the dimming electrodes light-shielded. Can do. Therefore, even if the second dimming electrode is light transmissive, good contrast can be obtained by preventing light leakage in the outer peripheral region, and a high-quality liquid crystal panel and liquid crystal display device can be provided. . Moreover, since the dimming electrode extends to the outer edge of the outer peripheral region, it can be said that the effect of improving the contrast is high. That is, if a light-shielding layer having a high light-shielding property is provided in the outer peripheral region due to high contrast, the seal may be insufficiently cured, but according to the present invention, light shielding in the outer peripheral region and sufficient curing of the entire seal are achieved. Both can be achieved.

The first substrate is that further having a arranged circuit so as to overlap the first dimming electrode on the outer peripheral region. According to such a configuration, since the circuit and the first dimming electrode overlap each other on the first substrate, the liquid crystal between the dimming electrodes is shielded, so that incident light from the outside to the circuit can be reduced. The light can be shielded to prevent deterioration of circuit characteristics (driver characteristics), and the incident light can be prevented from leaking to the display region, and high-quality display can be obtained by improving the contrast. Conversely, by making the liquid crystal between the dimming electrodes translucent (light transmissive), the circuit can be visually inspected over the light transmissive second dimming electrode, Laser correction or the like can also be performed. In particular, voltage control between the dimming electrodes can be performed regardless of the display state of the display region, and therefore, the defective portion can be easily identified by inspecting the image display state. For this reason, a series of operations such as visual inspection, identification of a defective portion, and correction thereof can be efficiently performed, and productivity is improved.

Further, the second substrate, the arrangement has been optical density (OD value) so as to overlap the second dimming electrodes that further having a light-shielding layer 3.5 and a thickness of 1 [mu] m. According to such a configuration, a double light shielding measure can be taken by the light shielding control between the light shielding layer and the above-described dimming electrode. For this reason, the above-described effects such as an improvement in display quality due to an improvement in contrast increase. At this time, since the light-shielding layer is thinner than the light-shielding measure using only the light-shielding layer, the above-described effect can be obtained while suppressing the display defect domain due to the thick light-shielding layer. In addition, since the above-described visual inspection or the like can be performed with a thin light-shielding layer, the above-described effect when the liquid crystal between the dimming electrodes is in a translucent state is not lost.

  Moreover, it is preferable that the said light shielding layer is arrange | positioned so that it may overlap with the said seal | sticker. According to such a configuration, high-quality display can be obtained by preventing light leakage at the arrangement portion of the seal.

  Further, when the width of the outer peripheral region is L (mm) and the width of the overlapping portion of the first dimming electrode and the second dimming electrode is M (mm), 0.6 ≦ M / L < 1 is preferably satisfied. According to such a configuration, high-quality display can be obtained by suppressing light leakage in the outer peripheral region.

  Further, the width of the outer peripheral region is L (mm), and the distance between the electrode close to the display region and the display region of the first dimming electrode and the second dimming electrode is A (mm). It is preferable that 0 <A ≦ L / 10. According to such a configuration, high-quality display can be obtained by suppressing light leakage near the boundary between the outer peripheral region and the display region.

  The seal preferably does not have a seal for liquid crystal injection. According to such a configuration, a so-called non-sealing type liquid crystal panel can be provided. According to the liquid crystal panel, the yield is improved by sufficient curing of the entire seal, and the non-sealing type liquid crystal panel is applied. Productivity can be greatly increased by a synergistic effect such as shortening of the tact time of liquid crystal filling produced by the single drop filling method.

  In Patent Document 1, a difference in expansion amount generated between the array substrate (TFT substrate) and the counter substrate due to a difference in thermal history generates a gap at the position of the display area end of both substrates, and light from the backlight is emitted from this gap. Has pointed out that the display quality may be significantly reduced due to leakage, and a technique for solving this problem is disclosed. Specifically, a light shielding electrode is formed in a frame shape so as to cover the periphery of the display area (the light shielding electrode and the pixel electrode are electrically insulated), and the light shielding electrode is used during image display. A potential that always displays black is supplied between the electrode and the counter electrode. As a result, even if the gap is generated when two substrates are bonded together, light leakage that occurs at the edge of the display area is suppressed, and light leakage is hardly visible to the outside. It is disclosed that the width of the light-shielding electrode needs to be wide at the position of the end of the display area described above, and specifically about 10 μm is sufficient.

  However, as can be seen from this numerical example, the light shielding electrode of Patent Document 1 is provided in the vicinity of the display area in a line, and extends to the vicinity of the outer edge of the non-display area (outer peripheral area) around the display area. It does n’t exist. On the other hand, in the present invention, since the dimming electrode extends to the outer edge of the outer peripheral region, it can be said that the effect of improving the contrast is high. In the technique of Patent Document 1, a potential that always displays black is supplied between the light shielding electrode and the counter electrode during image display. On the other hand, in the present invention, since the voltage between the dimming electrodes can be controlled regardless of the display state of the display area, the use range of the dimming electrodes is wide.

  According to the present invention, a liquid crystal panel and a liquid crystal display device with high display quality and reliability can be obtained by coexistence of light shielding in the outer peripheral region and sufficient curing of the entire seal.

  FIG. 1 is a schematic diagram for explaining a liquid crystal display device 50 according to an embodiment of the present invention. The liquid crystal display device 50 is generally called a transmission type. As shown in FIG. 1, the liquid crystal display device 50 includes a first liquid crystal panel 61, a backlight unit 70, and a driving device 80. The liquid crystal panel 61 and the backlight unit 70 may be collectively referred to as a liquid crystal unit.

  The liquid crystal panel 61 includes a display area 60A that is a central part of the panel and displays images, videos, characters, and the like, and an outer peripheral area 60B that surrounds the display area 60A and surrounds the display area 60A in a frame shape or a frame shape. And an external terminal region 60C provided with an external terminal 190, which is a portion protruding from the outer peripheral region 60B. Here, the display region 60A, the outer peripheral region 60B, and the external terminal portion 60C are not only two-dimensional regions in a plan view of the liquid crystal panel 61 but also the two-dimensional regions in the thickness direction of the liquid crystal panel 61 (substrates 100 and 200 described later). The three-dimensional region of the liquid crystal panel 61 projected and grasped in the stacking direction (see FIG. 2).

  The backlight unit 70 is arranged on the back surface of the liquid crystal panel 61 so as to be able to irradiate light (backlight) 71 (see FIG. 2) to the liquid crystal panel 61. The driving device 80 is connected to the liquid crystal panel 61 and the backlight unit 70, and here, a circuit, a device, and the like for driving and controlling the liquid crystal panel 61 and the backlight unit 70 are collectively referred to.

  The drive device 80 gives a drive instruction S60A to the display area 60A via the external terminal 190, and separately gives a drive instruction S60B to the outer peripheral area 60B via another external terminal 190. The two regions 60A and 60B are independently driven and controlled. In such a configuration, for example, as in the example of FIG. 1, the driving device 80 includes a display area driving unit 860A and an outer peripheral area driving unit 860B that operate independently from each other, and the liquid crystal panel 61 is used for the display area 60A and the outer peripheral area. This is possible by including drivers for 60B that operate independently of each other. As long as both the regions 60A and 60B can be driven and controlled independently, for example, both the drive units 860A and 860B and the two drivers may share a common portion. The driving device 80 further includes a backlight driving unit 870 that gives a driving instruction S70 to the backlight unit 70. Drive instructions S60A, S60B, and S70 include control signals and / or drive voltages.

  Next, FIG. 2 shows a cross-sectional view and a plan view for explaining the liquid crystal panel 61. 2A is a cross-sectional view taken along line 2A-2A in FIG. As shown in FIG. 2, the liquid crystal panel 61 includes a first substrate 100 and a second substrate 200 facing each other with a predetermined interval, and a liquid crystal layer (hereinafter also referred to as “liquid crystal”) disposed between the substrates 100 and 200. ) 300 and seal 400. The substrates 100 and 200 arranged opposite to each other are bonded by a seal 400 in the outer peripheral region 60B, and the liquid crystal 300 is filled in a container formed by the substrates 100 and 200 and the seal 400 (and therefore between the substrates 100 and 200). ing.

  The first substrate 100 includes a transparent substrate 110, a circuit layer 120 disposed on the transparent substrate 110, a pixel electrode 130 and a first dimming electrode 140 disposed on the circuit layer 120. In the liquid crystal panel 61, the first substrate 100 corresponds to a so-called TFT (Thin Film Transistor) substrate. The first substrate 100 includes an external terminal region 60C (see FIG. 1 or 3) outside the outer peripheral region 60B, and the external terminals 190 are connected to various circuits in the circuit layer 120.

  The transparent substrate 110 is a light-transmitting substrate, and is made of, for example, glass such as quartz glass, soda lime glass, borosilicate glass, low alkali glass, non-alkali glass, or plastic such as polyester or polyimide.

  The circuit layer 120 includes gate bus lines (not shown) arranged in stripes in the insulating layer, source bus lines (not shown) arranged in stripes extending in a direction intersecting the gate bus lines, and gate bus lines. A TFT (not shown) provided near the intersection of the source bus line, a terminal (not shown) for inputting a signal to the gate bus line and the source bus line, and a metal film or a semiconductor film are laminated. A circuit (or circuit element) 121 (for example, a driver of the pixel electrode 130) or the like is formed. As shown in FIG. 2, the circuit 121 is arranged in the outer peripheral region 60B.

  The pixel electrode 130 is made of a light transmissive material, for example, a transparent conductive material such as ITO (indium tin oxide), and is arranged in a matrix in the display region 60A, and is connected to the source bus line through the TFT. ing. Of the pixel electrodes 130 arranged in a matrix, the pixel electrodes 130 arranged on the outermost periphery are in contact with the outer edge of the display region 60A, that is, the boundary between the display region 60A and the outer periphery region 60B. In other words, the outermost peripheral pixel electrode 130 defines the display area 60A.

  Here, a plan view for explaining the light control electrode 140 is shown in FIG. As shown in FIGS. 2 and 3, the dimming electrode 140 is disposed in the outer peripheral region 60B and has a frame shape or a frame shape surrounding the display region 60A in the same manner as the outer peripheral region 60B. At this time, the dimming electrode 140 is provided from the vicinity of the boundary between the outer peripheral region 60B and the display region 60A to the vicinity of the outer edge (the edge farther from the display region 60A) of the outer peripheral region 60B. 2 and 3 illustrate the case where the outer edge of the dimming electrode 140 matches the outer edge of the outer peripheral region 60B. Due to such an arrangement, the width of the dimming electrode 140 (the width of the frame-shaped side portion of the dimming electrode 140 is substantially orthogonal to both the extending direction of the side portion and the stacking direction of the substrates 100 and 200). (Dimension in the direction in which it is performed) is on the order of millimeters or more, and the dimming electrode 140 faces (overlaps) the circuit 121.

  Note that the outer edge of the outer peripheral region 60B coincides with the edge or end of the substrate of the first substrate 100 (in other words, the transparent substrate 110) except for the portion where the external terminal region 60C is provided.

  The dimming electrode 140 is not in contact with the pixel electrode 130, and both electrodes 140 and 130 can be formed simultaneously by patterning a single transparent conductive film. Therefore, the light control electrode 140 is made of the same transparent conductive material as the pixel electrode 130 and has the same thickness as the pixel electrode 130. At this time, if it is extremely thick, the transmittance and the color purity are lowered at the time of display. Therefore, the thickness of the pixel electrode 130 (and therefore the thickness of the dimming electrode 140) is preferably about 80 to 120 nm. Although the light control electrode 140 can be formed of a material different from that of the pixel electrode 130, the light control electrode 140 can be formed without increasing the number of manufacturing steps by patterning a single transparent conductive film as described above. Can be formed.

  The first substrate 100 further includes a liquid crystal alignment film that covers the pixel electrode 130 and the light control electrode 140, and a polarizing plate that is disposed on the surface of the transparent substrate 110 that is the outer surface of the liquid crystal panel 61. These are omitted in 2nd class.

  The liquid crystal alignment film is made of polyimide, polyamic acid or the like, and is generally subjected to rubbing treatment. However, the rubbing treatment is not performed in the case of a vertical alignment film or a PDLC (polymer dispersed liquid crystal) display mode. In some cases.

  On the other hand, the second substrate 200 includes a transparent substrate 210, a counter electrode 230 and a second dimming electrode 240 disposed on the transparent substrate 210. In the liquid crystal panel 61, the second substrate 200 corresponds to a so-called color filter substrate. Similar to the transparent substrate 110, the transparent substrate 210 is a light transmissive substrate. The counter electrode 230 is a single light-transmitting material film (made of ITO or the like) that extends over the entire display area 60A, and faces the entire pixel electrode 130 arranged in a matrix.

  Here, FIG. 3B is a plan view for explaining the light control electrode 240. As shown in FIGS. 2 and 3, the dimming electrode 240 is formed in the same manner as the dimming electrode 140 described above, and faces (overlaps) the dimming electrode 140. Specifically, the dimming electrode 240 is disposed in the outer peripheral region 60B and surrounds the display region 60A in a frame shape or a frame shape like the outer peripheral region 60B. At this time, the dimming electrode 240 is provided from the vicinity of the boundary between the outer peripheral region 60B and the display region 60A to the vicinity of the outer edge of the outer peripheral region 60B. Due to such an arrangement, the width of the dimming electrode 240 is on the order of millimeters or more, and the dimming electrode 240 faces (overlaps) the dimming electrode 140. 2 and 3, the outer edge of the dimming electrode 240 coincides with the outer edge of the outer peripheral region 60B, and the end or edge of the dimming electrode 240 on the display region 60A side is the same as the dimming electrode 140 described above. The case where it exists in a position is illustrated.

  The outer edge of the outer peripheral region 60B described above coincides with the edge or end of the substrate of the second substrate 200 (in other words, the transparent substrate 210).

  The dimming electrode 240 is not in contact with the counter electrode 230, and both electrodes 240 and 230 can be formed simultaneously by patterning a single transparent conductive film. For this reason, the dimming electrode 240 is made of the same transparent conductive material as the counter electrode 230 and has the same thickness as the counter electrode 230. At this time, like the pixel electrode 130, the thickness of the counter electrode 230 (and therefore the thickness of the light control electrode 240) is preferably about 80 to 120 nm. Although the light control electrode 240 can be formed of a material different from that of the counter electrode 230, the light control electrode 240 can be formed without increasing the number of manufacturing steps by patterning a single transparent conductive film as described above. Can be formed.

  The second substrate 200 faces the pixel electrode 130, the liquid crystal alignment film covering the counter electrode 230 and the light control electrode 240, the polarizing plate disposed on the surface of the transparent substrate 210 corresponding to the outer surface of the liquid crystal panel 61, and the pixel electrode 130. 2 further includes a color filter arranged in a matrix and a light shielding layer arranged so as to partition adjacent color filters, but these are omitted in FIG.

  The substrates 100 and 200 are stacked such that the liquid crystal alignment films (not shown) face each other, in other words, the transparent substrates 110 and 210 are outside. Spacer columns (not shown) are arranged between the two substrates 100 and 200, and the substrates 100 and 200 are held at a predetermined interval by the spacer columns, and a gap is formed between the substrates 100 and 200. Liquid crystal 300 is filled in the gap.

  The seal 400 is disposed between the substrates 100 and 200 along the outer edge of the outer peripheral region 60B, and bonds the substrates 100 and 200 together. At this time, the seal 400 surrounds the liquid crystal layer 300, and in the case of the non-sealing type to which the one-drop filling method is applied, a sealing for liquid crystal injection is unnecessary, and thus the seal 400 has a frame shape or a frame shape ( (See FIG. 4). The seal 400 is disposed in the outer peripheral region 60B, but does not spread over the entire region 60B. In the example of FIG. 2, the case where the outer edge of the seal 400 coincides with the outer edge of the outer peripheral region 60B is illustrated. In particular, the seal 400 is disposed between the dimming electrodes 140 and 240 facing each other, and at this time, since the seal 400 does not spread over the entire outer peripheral region 60B as described above, the entire seal 400 is the both dimming electrodes 140 and 240. It overlaps with a part of.

  The seal 400 serves to seal the liquid crystal 300 between the substrates 100 and 200 and prevent air and moisture outside the panel from entering the liquid crystal layer 300. In general, an ultraviolet (UV) curable composition or a thermosetting composition is used as the sealant. For example, a composition (photocuring component) containing a curing agent based on an acrylic polymer and / or an epoxy polymer, an acrylic-epoxy polymer, or the like and reacting in a wavelength range from ultraviolet to visible light is used. Here, as the seal 400, a photo-curing sealant containing a photo-curing component that is cured by irradiation with light (ultraviolet light, visible light, X-rays, etc.), or a heat-curing component as well as a photo-curing component is further contained. A light / heat combination curable sealant is used. The thermosetting component is a composition that is cured by heating, and typically includes a resin. The width of the seal 400 (the dimension of the seal 400 in a direction substantially orthogonal to both the extending direction of the seal 400 and the stacking direction of the substrates 100 and 200) depends on various conditions such as the material of the seal 400, but is 0, for example. .About 3 mm to 3 mm.

  As described above, since the seal 400 does not spread over the entire outer peripheral region 60B and is disposed so as to overlap a part of the dimming electrodes 140 and 240, the liquid crystal layer 300 is not only in the display region 60A but also in the outer peripheral region. 60B also extends, and is also disposed between the dimming electrodes 140 and 240 in the outer peripheral region 60B except for the position where the seal 400 is disposed. Therefore, the alignment state of the liquid crystal 300 between the electrodes 140 and 240 can be controlled by controlling the voltage between the dimming electrodes 140 and 240.

  Here, it has been described that the driving device 80 can drive and control the display area 60A and the outer peripheral area 60B independently by the drive instructions S60A and S60B (see FIG. 1). Each pixel (or each cell) and the voltage between the dimming electrodes 140 and 240 in the outer peripheral region 60B are driven and controlled separately. Such independent control is performed, for example, by providing circuits and wirings independently between the dimming electrodes 140 and 240 and the pixel electrode 130 in the liquid crystal panel 61 and driving the drive device 80 as described above. This is possible by providing the portions 860A and 860B (see FIG. 1). Thereby, the voltage between the light control electrodes 140 and 240 can be controlled irrespective of the display state in the display area 60A.

  4 and 5 are a plan view and a cross-sectional view for explaining a method for manufacturing the liquid crystal panel 61. FIG. Here, in the case of a manufacturing method using a one-drop filling method, in other words, a case where the liquid crystal panel 61 is a non-sealing type, a seal (opening) for injecting liquid crystal is provided on the seal 400 to provide a dip method or a dispenser method. The liquid crystal panel 61 can be manufactured even if the liquid crystal is injected.

  First, an uncured seal 400 is applied to one of the first substrate 100 and the second substrate 200 that have been subjected to a rubbing process of the alignment film and can be bonded (see FIG. 4). In the example of FIG. 4, the case where the seal 400 is applied on the first substrate 100 is illustrated. In the case of the single drop filling method, the seal 400 is formed in a pattern that surrounds the display region 60A without a break. Thereafter, for example, a nematic liquid crystal material is dropped on the first substrate 100 or the second substrate 200 on which the seal 400 is formed. Then, the nematic liquid crystal material is sealed in the panel by overlapping the two substrates 100 and 200 in the vacuum chamber, whereby the liquid crystal layer 300 is formed.

  Next, the seal 400 is photocured by, for example, irradiating ultraviolet light (UV) 451 through the light control electrode 240 of the second substrate 200 (see FIG. 5). At this time, it is preferable to prevent the display region 60A from being irradiated with the ultraviolet rays 451 by irradiating the ultraviolet rays 451 through the photomask 452 as shown in FIG. In the example of FIG. 5, the light shielding portion of the photomask is provided only in the display region 60A. However, the light shielding portion may be extended into the outer peripheral region 60B to the extent that the seal 400 is not shielded. Note that the photomask 452 may be used even if it is in contact with the glass substrate 210 of the second substrate 200.

  According to the liquid crystal panel 61 and the liquid crystal display device 50, the following effects are obtained.

  As described above, the photocurable seal (agent) 400 is disposed so as to overlap the light control electrodes 140 and 240, and both the light control electrodes 140 and 240 are made of a light-transmitting material. When curing (in combination with thermosetting as described above), it is possible to irradiate the seal 400 with light over the light-transmitting dimming electrode 240 side. Thereby, the whole seal | sticker 400 can fully be hardened | cured. For this reason, both the substrates 100 and 200 can be firmly bonded, and the components in the seal can be prevented from being eluted and mixed into the liquid crystal layer from the insufficiently cured portion of the seal 400. Therefore, according to the liquid crystal panel 61 and the liquid crystal display device 50, high reliability and high display quality can be obtained.

  Here, it has been described that the thickness of the electrodes 130, 140, 230, and 240 is preferably about 80 to 120 nm. At this time, for example, when the light control electrode 240 is made of an ITO film having a thickness of about 100 nm and the transparent substrate 210 is a glass substrate having a thickness of about 1 mm, when the ultraviolet rays 451 are irradiated through these elements, that is, through the second substrate 200, an average of 80 It has been confirmed by the inventor that a transmittance of about% is obtained, and it is confirmed that a sufficient amount of ultraviolet rays can be obtained to cause photopolymerization and cure in a general ultraviolet curable seal.

  Further, since the voltage between the dimming electrodes 140 and 240 can be controlled regardless of the display state of the display region 60A, the liquid crystal 300 between the dimming electrodes 140 and 240 is put in a light-shielding state to display the outer periphery during image display. Light leakage in the region 60B can be prevented. Therefore, even if the dimming electrodes 140 and 240 are light transmissive, good contrast can be obtained by preventing light leakage in the outer peripheral region 60B, and high-quality display can be obtained. In addition, since the dimming electrodes 140 and 240 extend to the outer edge of the outer peripheral region 60B and are disposed on almost the entire outer peripheral region 60B, it can be said that the effect of improving the contrast is high.

  As described above, when a light-shielding layer having a high light-shielding property is provided in the outer peripheral region 60B due to high contrast as in the prior art, the seal may be insufficiently cured, but according to the liquid crystal panel 61 and the liquid crystal display device 50, Further, it is possible to achieve both light shielding of the outer peripheral region 60B and sufficient curing of the entire seal 400.

In addition, since the circuit 121 and the dimming electrode 140 are overlapped with each other on the first substrate 100, incident light from the outside to the circuit 121 can be reduced by putting the liquid crystal 300 between the dimming electrodes 140 and 240 in a light-shielding state. The light can be shielded to prevent deterioration of circuit characteristics (for example, characteristics of the pixel electrode driver), and leakage of the incident light to the display region 60A can be reduced to obtain a high-quality display by improving the contrast.

  On the contrary, the liquid crystal 300 between the dimming electrodes 140 and 240 is in a translucent (light transmissive) state, so that the circuit 121 is visually observed (including the case of using an optical microscope or the like) through the light transmissive dimming electrode 240. ) And laser correction or the like can be performed on the defective portion of the circuit 121. In particular, voltage control between the dimming electrodes 140 and 240 is possible regardless of the display state of the display area 60A. Therefore, by inspecting in a state where an image is displayed, for example, a lighting failure such as a line defect is displayed, A trouble location can be easily identified. For this reason, a series of operations such as visual inspection, identification of a defective portion, and correction thereof can be efficiently performed, and productivity is improved. Note that the voltage control between the light control electrodes 140 and 240 is not limited to digital on / off. If the voltage value is controlled in an analog manner (continuously), a visual inspection in a halftone state is performed. Etc. are also possible.

  By the way, as described above, if the under-cured part of the seal comes into contact with the liquid crystal material, the resin component in the seal may be eluted and mixed into the liquid crystal. Inviting and reducing the yield. In particular, in the one-drop filling method applied to non-sealing type panels, not only the under-cured part after the seal is cured but also the uncured seal before the seal is brought into contact with the liquid crystal material. Since it is larger than the insufficiently cured portion, it is considered that there are more opportunities for the above-mentioned elution / mixing as compared with the dip method in which liquid crystal is injected after the seal is cured.

  Here, even if the components of the seal 400 are mixed into the liquid crystal layer 300 before the seal is cured, the polymerization reaction of the seal progresses due to the ultraviolet irradiation 451, and the molecular weight of the seal 400 (resin thereof) increases and the substrate 100 and the substrate 200 are in contact with each other. If the adhesive strength increases, separation of the liquid crystal 300 and the resin component of the seal 400 proceeds, and as a result, the mixed state can be eliminated. Therefore, in view of this point, it is important to sufficiently cure the entire seal 400 in the one-drop filling method, and it can be said that it contributes to improvement in yield by preventing display quality defects caused by the above elution / mixing. Therefore, according to the liquid crystal panel 61 that can sufficiently cure the entire seal 400, the productivity can be significantly increased by the synergistic effect of the above-described yield improvement and the shortening of the tact time of the liquid crystal filling performed by the single drop filling method. it can.

  In addition, when the inventor conducted an aging test (70 ° C., 5 V drive, 500 hours) on the non-sealed liquid crystal panel manufactured by the one-drop filling method, the dimming electrodes 140 and 240 were not used and the outer peripheral region 60B was used. In the conventional liquid crystal panel using the light shielding layer, the display defect occurrence rate was 15%, but according to the liquid crystal panel 61 including the dimming electrodes 140 and 240, it was 0%.

Here, a more specific form of the light control electrodes 140 and 240 will be described. First, the width L of the outer peripheral region 60B shown in FIG. 2 and the width M of the overlapping portion of the two dimming electrodes 140 and 240 are as follows.
0.6 ≦ M / L <1 (Formula 1)
It is preferable to satisfy the relationship. The symbols “L” and “M” are used for the values of the widths L and M, and the units of the widths L and M are the same, and are “mm” here.

  The width L (value) is defined in the same manner as the dimming electrodes 140 and 240, and is the width of the frame-shaped side portion in the outer peripheral region 60B, and the extending direction of the side portion and the stacking of the substrates 100 and 200 The dimension in the direction substantially orthogonal to both directions. Further, the width M (value) of the overlapping portion of the dimming electrodes 140 and 240 is defined in the same manner as the dimming electrodes 140 and 240 for the overlapping portion. 2 and 3, both the dimming electrodes 140 and 240 have the same plane pattern and overlap without deviation in plan view, so that the width M of the overlapping portion is equal to the width of the dimming electrodes 140 and 240. equal.

  The upper limit (M / L <1) in Equation 1 is that when M / L ≧ 1, the dimming electrode 140 contacts or overlaps the pixel electrode 130 and the electrodes 140 and 130 cannot be driven and controlled independently. It is stipulated in view of the situation.

  On the other hand, the lower limit (0.6 ≦ M / L) in Formula 1 is defined from subjective evaluation and electro-optical evaluation of the display of the liquid crystal panel 61. Specifically, light leakage, contrast, and transmittance in the vicinity of the dimming electrodes 140 and 240, that is, the outer peripheral region 60B, were evaluated for a plurality of liquid crystal panels 61 having the same width L and different widths M. For the light leakage evaluation, the entire surface of the liquid crystal panel 61 was turned on (implemented for white display and halftone display, respectively), and the subjective evaluation of the influence of light leakage in the vicinity of the light control electrodes 140 and 240 was performed. Regarding contrast and transmittance, a voltage of 0 to 5 V is applied to the liquid crystal layer 300 between the dimming electrodes 140 and 240 to perform white display and black display at the electrodes 140 and 240, and brightness at each display is set. Based on the measured luminance, the contrast ratio (CR) and the panel transmittance were calculated. The luminance is measured under the condition that the color luminance meter BM5A (Topcon) is set at a position 350 mm from the display surface of the liquid crystal panel 61 (the surface on the second substrate 200 side), the light receiving angle is 1 °, and the light receiving area is 1 mmφ. I went there. In the measurement of the contrast ratio, as shown in FIG. 2B, the color luminance meter was set so that the center of the light receiving area AR was placed on the boundary between the display area 60A and the outer peripheral area 60B. The evaluation results thus obtained are shown in Table 1.

In Table 1, in the subjective evaluation of light leakage, “◯” represents “no light leakage effect”, “△” represents “some influence”, and “×” represents “light leakage NG level”. To express. Further, the transmittance is quantified at the reference luminance of 3000 cd / m ² of the backlight (B / L). The reference target values are contrast ratio ≧ 150 (0-5V), transmittance ≧ 6.5%, and the white brightness of the backlight is 3000 cd / m ² .

  According to the evaluation results in Table 1, it can be seen that if the value of M / L is about 0.65 or more, good characteristics can be obtained with respect to light leakage, contrast, and transmittance in the outer peripheral region 60B. Thus, according to the condition of Formula 1, high-quality display can be obtained by suppressing light leakage in the outer peripheral region 60B.

In addition, regarding the position of the end of the dimming electrodes 140 and 240 on the display region 60A side that extends closer to the display region 60A, the end and the outer edge of the display region 60A. Distance A is
0 <A ≦ L / 10 (Formula 2)
It is preferable to satisfy. Note that the symbol “A” is used for the value of the distance A, and the unit of the distance A is the same as the width L, which is “mm” here.

  In the example of FIGS. 2 and 3, both dimming electrodes 140 and 240 have the same plane pattern and overlap without deviation in plan view. In such a case, the end of any dimming electrode 140 or 240 is used as a reference. The same is true even if the width A is defined.

  The lower limit (0 <A) in Equation 2 is defined in view of the fact that when A = 0, the dimming electrode 140 is in contact with the pixel electrode 130 and the electrodes 140 and 130 cannot be driven and controlled independently.

  On the other hand, the upper limit (A ≦ L / 10) in Equation 2 is the light leakage from the dimming electrodes 140, 240 and the display area 60A (the gap), in other words, near the boundary between the display area 60A and the outer peripheral area 60B. It is specified from the result of subjective evaluation etc. That is, if A ≦ L / 10, the influence of light leakage is small, the contrast is high, and the display performance is sufficient. In addition, when satisfy | filling the conditions of Formula 2, it was confirmed by the inventors that the contrast was improved from 170 to 190. As described above, according to the condition of Expression 2, high-quality display can be obtained by suppressing light leakage near the boundary between the outer peripheral region 60B and the display region 60A.

  Next, FIGS. 6 and 7 are a sectional view and a plan view for explaining the second liquid crystal panel 62 according to the embodiment. As shown in FIG. 6, the liquid crystal panel 62 has a configuration in which a light shielding layer 260 is added between the glass substrate 210 and the dimming electrode 240 in the liquid crystal panel 61 (see FIG. 2) described above. As shown in FIGS. 6 and 7, the light shielding layer 260 is formed in the outer peripheral region 60B from the vicinity of the counter electrode 230 to the outer edge of the outer peripheral region 60B, and has a frame shape or a frame shape in plan view (see FIG. 7). I am doing. The light shielding layer 260 overlaps the dimming electrode 240 and the seal 400. 6 and 7, the light shielding layer 260 has the same planar pattern as the light control electrode 240 and overlaps without deviation in plan view.

  The light shielding layer 260 is made of, for example, a chromium film or a two-layer film of chromium / chromium oxide, or a resin containing a dark pigment. When the light shielding layer 260 is conductive, for example, the light shielding layer 260 is formed so as not to contact the counter electrode 240 in order to prevent the dimming electrode 240 from being short-circuited with the counter electrode 230 via the light shielding layer 260. Alternatively, an insulating film (not shown) may be disposed between the light shielding layer 260 and the dimming electrode 240. On the other hand, when the light shielding layer 260 is insulative, the light shielding layer 260 may be disposed so as to be in contact with the counter electrode 230, unlike the example of FIG. 6.

  The other structure of the liquid crystal panel 62 is the same as the liquid crystal panel 61 described above, and the liquid crystal panel 62 can be applied to the liquid crystal display device 50 (see FIG. 1) instead of the liquid crystal panel 61.

  According to the liquid crystal panel 62, double light shielding measures can be taken by the light shielding control between the light control electrodes 140 and 240 and the light shielding layer 260. For this reason, the above-described effects such as an improvement in display quality due to an improvement in contrast are increased. At this time, the light shielding layer 260 may be thinner than the light shielding measure using only the light shielding layer 260. The thick light-shielding layer forms large irregularities on the alignment film application surface, leading to increased unevenness of alignment film formation and non-uniformity such as rubbing, which causes display defect domains (switching domains) and causes display defects. Although light leakage is caused, the thin light-shielding layer 260 of the liquid crystal panel 62 can achieve the above-described high-quality display effect while suppressing such display defect domains. In addition, since the above-described visual inspection or the like can be performed with the thin light-shielding layer 260, the above-described effects when the liquid crystal 300 between the dimming electrodes 140 and 240 is in a translucent state are not lost. Further, since the light shielding layer 260 overlaps the seal 400, light leakage at the portion where the seal 400 is disposed can be prevented, and high-quality display can be obtained.

  In addition, about the light shielding layer 260, if the optical density (OD value) is about 3.5 and thickness is about 1 micrometer, it was confirmed by the inventor that light shielding property, visual inspection, etc. can be made compatible.

  By the way, when controlling the voltage between the light control electrodes 140 and 240, it is not always necessary to control the potentials of both electrodes 140 and 240, and the potential of one light control electrode 140 or 240 may be fixed. At this time, considering that the counter electrode 230 is generally grounded, when the dimming electrode 240 is fixed to the ground potential, the configuration shown in the sectional view of FIG. 8 can be adopted.

  That is, as in the third liquid crystal panel 63 shown in FIG. 8, in the liquid crystal panel 61 (see FIG. 2), the dimming electrode 240 and the counter electrode 230 are light corresponding to an element in which both electrodes 240 and 230 are coupled or contacted. The single electrode 250 having transparency may be used instead. At this time, in the electrode 250, a portion in the display region 60A corresponds to the counter electrode 230, and a portion in the outer peripheral region 60B corresponds to the dimming electrode 240. The other configuration of the liquid crystal panel 62 is the same as that of the liquid crystal panel 61 described above, and the liquid crystal panel 63 can be applied to the liquid crystal display device 50 (see FIG. 1) instead of the liquid crystal panel 61. According to the liquid crystal panel 63, the patterning process for separating the counter electrode 230 and the dimming electrode 240 can be eliminated, and the productivity is improved.

  Further, the liquid crystal panels 62 and 63 (see FIGS. 6 and 8) described above may be combined like a fourth liquid crystal panel 64 shown in the sectional view of FIG. That is, as shown in FIG. 9, the liquid crystal panel 64 has a configuration in which the dimming electrode 240 and the counter electrode 240 are integrated in the liquid crystal panel 62 to provide a single electrode 250, in other words, the liquid crystal panel 63 is transparent. This corresponds to a configuration in which the light shielding layer 260 is disposed between the substrate 210 and the portion of the electrode 250 forming the light control electrode 240. Other configurations of the liquid crystal panel 64 are the same as those of the liquid crystal panels 61 to 63 described above, and the liquid crystal panel 64 can be applied to the liquid crystal display device 50 (see FIG. 1) instead of the liquid crystal panel 61.

  As mentioned above, although embodiment of this invention was described, the technical scope of this invention is not limited to the range as described in the above-mentioned embodiment. It will be understood by those skilled in the art that the above-described embodiments are exemplifications, and that various modifications can be made to combinations of the respective components and processing processes, and such modifications are also within the scope of the present invention. By the way.

  For example, in the above description, the case where the first substrate 100 and the second substrate 100 correspond to so-called TFT substrates and color filter substrates has been described, but the configurations of both the substrates 100 and 200 are not limited thereto. For example, even when the first substrate 100 corresponds to a TFT substrate with a color filter (so-called color filter on TFT (CF on TFT) substrate) and the second substrate 200 corresponds to a counter substrate without a color filter, the above description is valid. It is.

  In the above description, the TFT is exemplified as the liquid crystal driving element, but other active driving elements such as MIM (Metal Insulator Metal) may be used. Furthermore, the dimming electrodes 140 and 240 can be applied to a passive (multiplex) type liquid crystal panel that does not use a driving element. Further, although the transmissive liquid crystal display device 50 is illustrated, the liquid crystal panel 61 and the like can be applied to a reflective type and a transmissive / reflective type.

  The liquid crystal panel 61 and the like can be applied to, for example, an image shift panel and a parallax barrier panel. The image shift panel optically sequentially shifts pixels, a liquid crystal panel that modulates the polarization state of light, and a birefringent element that shifts an optical path according to the polarization state of light emitted from the liquid crystal panel. At least one combination. The parallax barrier panel is capable of displaying an image shift panel or a three-dimensional video, and can display a stereoscopic video by combining with a video display element having a left-eye pixel and a right-eye pixel. Liquid crystal panels 61 and the like, and image shift panels and parallax barrier panels to which these are applied include, for example, cellular phones, PDAs (Personal Digital Assistance), personal computers, flat-screen TVs, medical displays, car navigation systems, amusement devices, etc. Can be used.

These are the schematic diagrams for demonstrating the liquid crystal display device which concerns on embodiment of this invention. These are sectional drawing and a top view for demonstrating the 1st liquid crystal panel which concerns on embodiment of this invention. These are top views for demonstrating the light control electrode which concerns on embodiment of this invention. These are the top views for demonstrating the manufacturing method of the 1st liquid crystal panel which concerns on embodiment of this invention. These are sectional views for explaining a method for manufacturing a first liquid crystal panel according to an embodiment of the present invention. These are sectional drawings for demonstrating the 2nd liquid crystal panel which concerns on embodiment of this invention. These are top views for demonstrating the light shielding layer which concerns on embodiment of this invention. These are sectional drawings for demonstrating the 3rd liquid crystal panel which concerns on embodiment of this invention. These are sectional drawings for demonstrating the 4th liquid crystal panel which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 50 Liquid crystal display device 61-64 Liquid crystal panel 60A Display area 60B Outer periphery area | region 80 Drive apparatus 100 1st board | substrate 121 Circuit 130 Pixel electrode 140 1st light control electrode 200 2nd board | substrate 240 2nd light control electrode 260 Light-shielding layer 300 Liquid crystal layer 400 Seal A Distance L, M width

Claims (6)

A liquid crystal display device comprising: a liquid crystal panel; and a driving device that drives and controls the liquid crystal panel,
The liquid crystal panel is
A pixel electrode disposed in the display region, and a first dimming electrode disposed in the outer peripheral region around the display region so as not to contact the pixel electrode and extending to the vicinity of the outer edge of the outer peripheral region A first substrate comprising:
A second substrate having a light transmissive second dimming electrode disposed opposite to the first dimming electrode in the outer peripheral region, and disposed opposite to the first substrate;
A first polarizing plate disposed on an outer surface of the first substrate;
A second polarizing plate disposed on the outer surface of the second substrate;
A liquid crystal layer disposed between the first substrate and the second substrate so as to extend between the first dimming electrode and the second dimming electrode;
A seal containing a photocuring component, disposed between the first substrate and the second substrate so as to overlap the first dimming electrode and the second dimming electrode, and sealing the liquid crystal layer; Including
Together with the first substrate, the have a arranged circuit so as to overlap the first dimming electrode on the outer peripheral region,
The second substrate further includes a light shielding layer disposed so as to overlap the second dimming electrode and having an optical density (OD value) of 3.5 and a thickness of 1 μm.
The liquid crystal display device can control the voltage between the first dimming electrode and the second dimming electrode in an analog manner regardless of the display state of the display area.
By preventing the liquid crystal between the first dimming electrode and the second dimming electrode from being in a light-shielding state, light leakage in the outer peripheral region is prevented during image display,
A liquid crystal display device characterized in that the circuit can be visually inspected through the second dimming electrode in a state where an image is displayed . The liquid crystal display device according to claim 1 , wherein the light shielding layer is disposed so as to overlap the seal . When the width of the outer peripheral region is L (mm) and the width of the overlapping portion of the first dimming electrode and the second dimming electrode is M (mm),
0.6 ≦ M / L <1
The liquid crystal display device according to claim 1 , wherein: When the width of the outer peripheral region is L (mm) and the distance between the electrode close to the display region and the display region of the first dimming electrode and the second dimming electrode is A (mm) ,
0 <A ≦ L / 10
The liquid crystal display device according to claim 1, wherein: 5. The liquid crystal display device according to claim 1, wherein the seal does not have a seal for liquid crystal injection . A pixel electrode disposed in the display region, and a first dimming electrode disposed in the outer peripheral region around the display region so as not to contact the pixel electrode and extending to the vicinity of the outer edge of the outer peripheral region A first substrate comprising:
A second substrate that includes a light transmissive second dimming electrode disposed opposite to the first dimming electrode in the outer peripheral region, and is disposed opposite to the first substrate;
A first polarizing plate disposed on an outer surface of the first substrate;
A second polarizing plate disposed on the outer surface of the second substrate;
A liquid crystal layer disposed between the first substrate and the second substrate so as to extend between the first dimming electrode and the second dimming electrode;
A seal containing a photocuring component, disposed between the first substrate and the second substrate so as to overlap the first dimming electrode and the second dimming electrode, and sealing the liquid crystal layer;
A light shielding layer disposed on the second substrate so as to overlap the second light control electrode and having an optical density (OD value) of 3.5 and a thickness of 1 μm;
The first substrate has a circuit disposed in the outer peripheral region so as to overlap the first dimming electrode, and a part of the circuit is disposed so as to overlap the seal. LCD panel.

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