JP2006178502A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display with high reliability by curing a sealing material intruding into between a pair of glass substrates without leaving an uncured portion so as to prevent display failure caused by uncured sealing of a sealing material. <P>SOLUTION: The liquid crystal display has a liquid crystal panel produced by forming a light shielding film 13 or lines which do not transmit light on opposing faces of a pair of glass substrates, applying a sealing material on the opposing faces including an injection port 3 for a liquid crystal, and laminating the pair of glass substrates to each other. The sealing material 6 to seal the injection port 3 is a UV curing or visible ray curing resin, and at least a part of the resin is drawn into between the pair of glass substrates. A notch 15 which is a transmitting part to allow UV rays or visible light to transmit is formed on at least one substrate in a part near the injection port 3 of the light shielding film 13 or the lines. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device. More specifically, the present invention relates to a liquid crystal display device that can obtain high reliability even when there are variations in manufacturing conditions such as the installation of a light shielding film or wiring near the injection port.

  8 to 9 show an apparatus described in Japanese Patent Application Laid-Open No. 58-44420 as an example of a conventional liquid crystal display device. 8 is a plan view showing the structure of a conventional liquid crystal display device, and FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG.

  8-9, 21 is a pair of glass substrates having transparent electrodes and metal wiring (not shown) formed on the opposite surface side, 22 is a resin sealing material for bonding the pair of glass substrates 21, 23 Is an injection port for injecting the liquid crystal 25 formed in a part of the sealing material 22, 24 is a spacer dispersed to keep the distance between the pair of glass substrates 21 constant, and 25 is a gap between the pair of glass substrates 21. A liquid crystal 26 and a sealing material 26 are provided to prevent the liquid crystal 25 from leaking.

  From the problem of improving the throughput of the sealing process and the pot life of the material (usable time after mixing), for example, as disclosed in JP-A-58-44420, An ultraviolet curable resin is used. As shown in FIG. 9, after applying the sealing material 26, the resin sealing material 26 is cured by irradiating the ultraviolet light in the direction of the arrow 27 using a lamp that generates ultraviolet light.

  In order to increase the sealing effect after application, the sealing material 26 is allowed to enter the gap between the pair of glass substrates 21 by capillary action. Usually, as shown in FIG. It is in a state of intrusion. 9, the portion of the sealing material 26 that has entered the gap between the pair of glass substrates 21 is cured by the ultraviolet rays 28 that wrap around from the lateral direction (upward or downward in FIG. 9). Thus, the portion into which the sealing material 26 has entered has a high function of sealing the opening of the injection port 23, and not only prevents the liquid crystal inside the liquid crystal display device from leaking, but also has an effect of preventing entry of moisture and the like from the outside. high. Therefore, in the manufacture of the liquid crystal display device, the sealing material is positively inserted between the glass substrates in order to improve the reliability of the device. Generally, the penetration distance is adjusted to be about 0.1 to 1 mm.

  Incidentally, a recent high-performance liquid crystal display device has a structure as shown in FIG. 10, for example. Reference numeral 29 denotes a color filter substrate on which a color filter layer 31 for coloring a display is formed, and 30 denotes a TFT substrate on which a thin film transistor is formed. In addition, since it is not desirable for light to transmit in a region other than the display portion 32, a light shielding film 33 using a chromium thin film or the like is formed in the peripheral portion of one substrate 29 in the region other than the display portion. In particular, in a TFT-LCD color liquid crystal display device constituted by using a thin film transistor-formed substrate as shown in FIG. 10 and a color filter substrate, the formation of this light shielding film is indispensable. It is formed on the substrate side.

  On the other TFT substrate 30 on which the light shielding film is not formed, a signal metal wiring 34 for driving the liquid crystal 25 is formed. Recent high-performance liquid crystal display devices are designed to maximize the size of the display portion with respect to the outer size, and thus the distance between the display portion and the outer peripheral line of the liquid crystal panel is reduced. Further, in the injection port portion of the liquid crystal display device, a portion where the sealing material 26 is sandwiched between the light shielding film 33 and the metal wiring 34 is formed.

  As described above, the sealing material 26 penetrates between the pair of glass substrates 29 and 30, and at least a part of the sealing material 26 is sandwiched between films such as the light shielding film 33 and the metal wiring 34 that do not transmit light. In some cases, the sandwiched portion is not irradiated with a sufficient amount of ultraviolet or visible light to be cured, and as a result, an uncured sealing material remains. This uncured encapsulant is in contact with the liquid crystal, and during the long-term use of the liquid crystal display device, the uncured encapsulant gradually diffuses into the liquid crystal, and the liquid crystal in the portion where the encapsulant diffuses is Characteristics such as voltage-transmittance characteristics and specific resistance deteriorate. Therefore, as a result, display performance deterioration near the injection port, specifically, a local change in luminance is caused. In particular, a decrease in the specific resistance of the liquid crystal leads to a fatal failure for the TFT-LCD, and therefore the sealing material needs to be sufficiently cured.

  For example, FIG. 11 shows an example of the luminance distribution of the liquid crystal panel when the sealing material of the inlet remains in an uncured state. According to FIG. 11, it can be seen that the luminance is partially increased near the inlet of the liquid crystal panel. This is because the specific resistance of the liquid crystal is low in the vicinity of the injection port.

  The present invention has been made to solve such problems, and in order to prevent the occurrence of display defects due to the uncured sealing material, the sealing material that has entered between the pair of glass substrates is uncured. An object of the present invention is to provide a highly reliable liquid crystal display device which is cured so as not to remain.

In the liquid crystal display device of the present invention, a light-shielding film or wiring that does not transmit light is formed on the opposing surfaces of a pair of substrates, and a sealing material is applied so as to form a liquid crystal injection port on the opposing surfaces. Is a liquid crystal display device comprising a liquid crystal panel bonded to each other,
The sealing material that seals the injection port is a resin that cures with ultraviolet light or visible light,
At least a portion of the resin is drawn between the pair of substrates;
In the portion of the light shielding film or wiring in the vicinity of the injection port, at least one of the substrates is formed with a transmission portion capable of transmitting the ultraviolet light or visible light.

  It is preferable that the aperture ratio of the transmission portion is 20% or more.

  It is preferable that the transmission part is a notch formed in a part near the injection port of the light shielding film or wiring.

  It is preferable that the transmission part is composed of a plurality of parts.

  It is preferable that the transmission part is a gap between two adjacent wirings of the wiring.

  It is preferable that the opening ratio of the gap is 20% or more, and the opening ratio of the gap in a portion separated from the injection port is 20% or less.

  It is preferable that a portion of the wiring near the injection port is partially narrowed.

  The transmissive part is preferably a circular or polygonal opening formed in the light shielding film or wiring.

  It is preferable that the transmissive portion is a region inside the opening formed in the light shielding film or the wiring and outside the dot-like or belt-like pattern formed inside the opening.

  According to the first aspect of the present invention, even if the sealing material penetrates between the pair of substrates, the transparent portion is cured by the irradiated ultraviolet rays or visible light, and the uncured sealing material diffuses into the liquid crystal. Can be prevented. As a result, it is possible to prevent the luminance of the liquid crystal panel from becoming uneven.

  According to the fifth to eighth aspects of the invention, in a liquid crystal display panel having an opaque part such as a metal wiring, even if the sealing material enters between the substrates, it passes through a large number of minute transmission parts and is irradiated with ultraviolet rays or visible light. The sealing material is cured, and the uncured sealing material can be prevented from diffusing into the liquid crystal. As a result, it is possible to prevent the luminance of the liquid crystal panel from becoming uneven.

  In particular, according to the inventions described in claims 7 to 8, it is possible to prevent the uncured sealing material from diffusing into the liquid crystal and to secure a sufficiently low resistance wiring for driving the liquid crystal. Is possible.

  According to the invention of claim 10, the uncured sealing material can be prevented from diffusing into the liquid crystal, and the uniformity of the gap between the pair of substrates can be achieved by the dot-like or strip-like pattern. Can be secured.

  Next, the liquid crystal display device of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory plan view showing an embodiment of the liquid crystal display device of the present invention, FIG. 2 is an enlarged view of the vicinity of the injection port of FIG. 1, FIG. FIG. 5 is an enlarged view of the vicinity of an injection port of a liquid crystal display device when a wiring showing another embodiment of the liquid crystal display device of the invention is bypassed, and FIG. 5 shows a wiring showing still another embodiment of the liquid crystal display device of the present invention. FIG. 6 is an enlarged view of the vicinity of the injection port of the liquid crystal display device when partially thinning, and FIG. 6 shows the injection port of the liquid crystal display device having a dotted pattern showing still another embodiment of the liquid crystal display device of the present invention. FIG. 7 is an enlarged view of the vicinity and FIG. 7 is a graph showing the luminance distribution near the inlet of the liquid crystal display device of FIG.

Embodiment 1
1 to 3 show a liquid crystal display device having a cutout 15 for transmitting ultraviolet light or light. Here, reference numerals 9 and 10 denote a pair of glass substrates, and a light-shielding film 13 and a wiring 14 that do not allow light to pass through are formed on the respective facing surfaces. 1 to 3, 2 is a resin sealing material for bonding a pair of glass substrates 9, 10, 3 is an injection port for injecting liquid crystal 5 formed in a part of the sealing material 2, 4 is a spacer dispersed to keep the distance between the pair of glass substrates 9 and 10 constant, 5 is a liquid crystal injected into the gap between the pair of glass substrates 21, and 6 is provided to prevent the liquid crystal 5 from leaking. Sealing material.

  The sealing material 6 is a resin that is cured by irradiation with ultraviolet rays or visible light. For example, an ultraviolet curable acrylic resin or an ultraviolet curable epoxy resin is used.

  The wiring 14 is made of, for example, an aluminum thin film wiring of about 1000 angstroms provided on the upper side of the glass substrate 9 to electrically connect the signal line at one end of the glass substrate 10 and the signal line at the other end. Become.

  The light shielding film 13 is provided from, for example, a chromium thin film having a thickness of about 1000 angstroms provided to prevent unnecessary light from passing through the pair of glass substrates 9 and 10. Become.

  As shown in FIGS. 2 to 3, a notch 15 is formed in the light shielding film 13 in the vicinity of the injection port 3 as a transmission part for transmitting ultraviolet light or visible light.

  The notch 15 is wide enough to allow ultraviolet rays or visible light irradiated from the outside to sufficiently enter the portion of the sealing material 6 that has entered between the substrates, for example, the notch width W is about 20 mm and the notch depth D is about 2 mm. By forming in a wide area, it is possible to sufficiently irradiate the portion of the sealing material 6 that has entered between the substrates of the sealing material 6 (can irradiate almost 100% light).

  In the liquid crystal panel in which the injection port portion is configured as described above, after injecting the liquid crystal material, an ultraviolet curable resin, for example, 3052 (trade name: manufactured by Three Bond Co., Ltd.) is used as the sealing material 6 in the injection port. The injection port is sealed with a sealing material while controlling so that the amount of penetration into the substrate is 0.05 mm or more, preferably about 1 mm, and then irradiated with ultraviolet rays of about 5000 mj to the outside of the substrate. The sealing material that has entered between the protruding portion and the substrate can be completely cured.

  FIG. 7 shows a graph of the measurement result of the luminance distribution of the liquid crystal display panel having the notch 15. As can be seen from the graph of FIG. 7, the luminance is uniform even near the injection port of the liquid crystal panel, and the specific resistance of the liquid crystal is kept normal in the vicinity of the injection port.

  Note that the above-described effects can be obtained by forming notches in the wiring 14 instead of forming the notches 15 in the light shielding film 13 as shown in FIG.

Embodiment 2
In FIG. 4, an opening 16, which is a transmission part, is formed by bypassing a region where the wiring 14 enters the gap between the substrates of the sealing material 6 (corresponding to the gap between the glass substrates 9 and 10 in FIG. 3 described above). An example in which is formed is shown. In this way, the wiring 14 bypasses the vicinity of the sealing material 6, thereby ensuring an opening necessary for transmitting ultraviolet light or visible light. The other points are common to the first embodiment.

Embodiment 3
If the wiring 14 cannot be bypassed as in the second embodiment due to design constraints, the aperture ratio of the transmission part for transmitting ultraviolet light or visible light in consideration of the irradiation amount of ultraviolet light is light. By designing the width of the wiring so that it is 20% or more (that is, the light-shielded area is less than 80%) with respect to the irradiated portion, the opening necessary for transmitting ultraviolet light or visible light is provided. Can be secured. The other points are common to the first embodiment.

Embodiment 4
In the third embodiment, the case where the wiring width and interval can be freely designed has been described. However, when the liquid crystal panel is enlarged, the wiring resistance is reduced in order to reduce the wiring resistance for normal transmission of the drive signal. There is a case where the width needs to be increased and a sufficient aperture ratio cannot be secured. In such a case, the aperture ratio of the gap between adjacent wirings near the injection port may be 20% or more, and the aperture ratio of the gap in the part separated from the injection port may be 20% or less. .

  Specifically, as shown in FIG. 5, only in the vicinity of the region that enters the gap between the substrates of the sealing material 6 (corresponding to the gap between the glass substrates 9 and 10 in FIG. 3 described above) in the vicinity of the injection port 3. By partially thinning the wiring 14, it is possible to secure a minimum number of gaps 17 necessary for irradiation with ultraviolet rays or visible light, and as a result, the sealing material 6 that has entered between the substrates is cured. Can be made. The other points are common to the first embodiment.

Embodiment 5
Although not shown, even if a circular or polygonal opening is formed in the light shielding film 13 or the wiring 14 in the vicinity of the injection port 3 as the transmission portion, the minimum necessary for irradiation with ultraviolet rays or visible light. The plurality of openings can be secured, and as a result, the sealing material 6 that has entered between the substrates can be cured. The other points are common to the first embodiment.

Embodiment 6
In the case of the first embodiment, since the notch 15 is formed in the light shielding film 13, the distance between the pair of substrates of the liquid crystal panel, that is, a gap defect may occur in the notch 15 and its vicinity. This is because the light shielding film 13 is notched, so that there is a step corresponding to the film thickness of the light shielding film 13 and the gap is reduced. In this embodiment, in order to eliminate such a problem, in order to make the gap uniform in the notch 15 formed in the light shielding film 13, the aperture ratio with respect to the portion irradiated with light is 20% or more (that is, the light shielding. As shown in FIG. 6, it is effective to leave the pattern 18 of the light-shielding film 13 in the form of dots or strips at a ratio of less than 80%).

  In the sixth embodiment, the transmission part is an area inside the notch 15 and outside the dot-like or belt-like pattern 18. The other points are common to the first embodiment.

  In the sixth embodiment, the above-described effects can be obtained by forming notches and patterns in the wiring 14 instead of forming the notches 15 and the dot-like or strip-like patterns 18 in the light shielding film 13.

  As described above, the liquid crystal display device of the present invention can be suitably applied to recent high-performance color liquid crystal display devices and the like that need to form wirings and light shielding films in narrow regions other than the display region.

It is a plane explanatory view showing one embodiment of a liquid crystal display device of the present invention. FIG. 2 is an enlarged view of the vicinity of an injection port in FIG. It is the III-III sectional view taken on the line of FIG. FIG. 10 is an enlarged view of the vicinity of an injection port of a liquid crystal display device when a wiring showing another embodiment of the liquid crystal display device of the present invention is bypassed. FIG. 10 is an enlarged view of the vicinity of an injection port of a liquid crystal display device when a wiring showing a further embodiment of the liquid crystal display device of the present invention is partially thinned. It is an enlarged view of the vicinity of the injection port of a liquid crystal display device having a dot pattern showing still another embodiment of the liquid crystal display device of the present invention. 2 is a graph showing a luminance distribution in the vicinity of an injection port of the liquid crystal display device of FIG. 1. It is a top view of the conventional liquid crystal display device. It is the IX-IX sectional view taken on the line of FIG. It is sectional drawing of the conventional color liquid crystal display device. It is a graph which shows distribution of the brightness | luminance near the injection hole of the conventional color liquid crystal display device.

Explanation of symbols

3 Inlet 6 Sealing material 9, 10 Glass substrate 13 Light shielding film 14 Wiring 15 Notch 16 Opening 17 Gap 18 Pattern

Claims (9)

A liquid crystal panel in which a light-shielding film or wiring that does not transmit light is formed on opposite surfaces of a pair of substrates, a sealing material is applied to form a liquid crystal injection port on the opposite surfaces, and the pair of substrates are bonded to each other. A liquid crystal display device comprising:
The sealing material that seals the injection port is a resin that cures with ultraviolet light or visible light,
At least a portion of the resin is drawn between the pair of substrates;
A liquid crystal display device in which a transmissive portion capable of transmitting the ultraviolet light or visible light is formed on at least one substrate in a portion near the injection port of the light shielding film or wiring. The liquid crystal display device according to claim 1, wherein an aperture ratio of the transmissive portion is 20% or more. The liquid crystal display device according to claim 1, wherein the transmissive portion is a notch formed in a portion near the injection port of the light shielding film or wiring. The liquid crystal display device according to claim 1, wherein the transmissive portion includes a plurality of portions. The liquid crystal display device according to claim 4, wherein the transmissive portion is a gap between two adjacent wirings. The liquid crystal display device according to claim 5, wherein an opening ratio of the gap is 20% or more, and an opening ratio of the gap in a portion separated from the injection port is 20% or less. The liquid crystal display device according to claim 7, wherein a portion of the wiring in the vicinity of the injection port is partially narrowed. The liquid crystal display device according to claim 4, wherein the transmissive portion is a circular or polygonal opening formed in the light shielding film or wiring. The said transmission part is an area | region inside the opening part formed in the said light shielding film or wiring, Comprising: The area | region outside the dotted | punctate or strip | belt-shaped pattern formed inside the said opening part. Liquid crystal display device.

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