JP2010139568A - Liquid crystal display device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of reliably preventing occurrence of low-temperature impact air bubbles in a liquid crystal layer 13. <P>SOLUTION: Columnar spacer includes: first spacers for prescribing an interval between a first substrate 11 and a second substrate 12 by bringing the tip end of the first spacers into contact with the first substrate 11; and second spacers of which the height is lower than that of the first spacers. A display area 20 includes a first area 21 in which the first spacers and the second spacers are arranged so as to coexist in a specified proportion and a second area 22 which has an area smaller than that of the first area 21 and where only a plurality of the first spacers are arranged. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device having columnar spacers and a method for manufacturing the same.

  A liquid crystal display device has a structure including an element substrate on which a plurality of pixel electrodes and switching elements are formed, a counter substrate disposed to face the element substrate, and a liquid crystal layer sealed between these substrates. Have. A spacer for defining the thickness of the liquid crystal layer is provided between the element substrate and the counter substrate. Conventionally, it is known to provide transparent spherical particles (beads) made of glass or synthetic resin as a spacer. A large number of particulate spacers are dispersed and interposed between the pair of substrates.

  However, since the particulate spacer is a transparent particle, there is a problem that light leakage occurs during black display. In addition, light leakage also occurs when the arrangement of liquid crystal molecules is disturbed in the vicinity of the particulate spacer in the display region. As a result, the contrast is lowered and the display quality is lowered.

  Therefore, it is known to form columnar spacers (photo spacers) in a light shielding region between pixels using a photosensitive resin. A plurality of columnar spacers are formed on the element substrate or the counter substrate, and have the same cross-sectional area in the direction parallel to the substrate and the same height. Since the columnar spacer is formed at a position avoiding the display area in the pixel, in addition to improving the contrast, the impact resistance of the liquid crystal display device is also improved.

  By the way, when manufacturing the above-mentioned liquid crystal display device, these substrates are bonded to each other through a sealing member in a state where the counter substrate on which the columnar spacers are formed and the element substrate are arranged in parallel to each other. At this time, if the cross-sectional area of the columnar spacer is relatively small, the columnar spacer is likely to be deformed by the stress applied at the time of bonding, so that it is difficult to maintain a uniform gap between the substrates (that is, the thickness of the liquid crystal layer). Therefore, the cross-sectional area of the columnar spacer needs to be increased to some extent as a whole. However, if the arrangement density of the columnar spacers is increased, bubbles (low temperature shock bubbles) are likely to be generated in the liquid crystal layer.

  That is, when the usage environment of the liquid crystal display device is a low temperature environment such as −20 ° C., all the components of the liquid crystal display device tend to contract. Since the contraction rate of the liquid crystal is the largest among the constituent members, it tends to shrink in the direction of reducing the gap between the substrates. At this time, if the deformation amount of the columnar spacer cannot follow the contraction force of the liquid crystal, a negative pressure is generated inside the liquid crystal cell, and thus low-temperature shock bubbles are likely to be generated in the liquid crystal layer.

  On the other hand, Patent Document 1 discloses that two types of columnar spacers are formed. As shown in FIG. 5 which is a plan view of the counter substrate and FIG. 6 which is an enlarged cross-sectional view of the counter substrate, the counter substrate 101 has columnar spacers 103 formed on the glass substrate 102. The columnar spacer 103 is configured by a main spacer 104 that defines the gap between the substrates by contacting the element substrate (not shown) and a sub-spacer 105 whose height from the surface of the glass substrate 102 is lower than that of the main spacer 104. ing.

As shown in FIG. 5, the main spacer 104 and the sub-spacer 105 are arranged in a dispersed manner in the display area. In this way, the generation of low-temperature shock bubbles is suppressed while appropriately maintaining the thickness of the liquid crystal layer, which is the gap between the substrates.
JP 2003-121857 A

  By the way, as a method for injecting liquid crystal between a pair of substrates, a drop injection method (ODF: One Drop Fill) in which the substrates are bonded to each other after dropping the liquid crystal on the substrates is reduced, and the gap between the substrates is reduced. It is regarded as important because it becomes possible.

  In this dropping injection method, in order to determine an appropriate dropping amount of the liquid crystal, it is conceivable to measure the height of the main spacer with an optical device. That is, since the height of the main spacer corresponds to the cell gap (the thickness of the liquid crystal layer), the necessary amount of liquid crystal can be calculated by detecting the height.

  However, it is difficult to clearly distinguish the main spacer and the sub-spacer by an optical device, and there is a possibility that the height of the sub-spacer is erroneously measured. As a result, there is a problem that the amount of liquid crystal dropped is less than an appropriate amount, and low-temperature shock bubbles are generated in the formed liquid crystal layer.

  Although it may be possible to differentiate by providing a difference in the cross-sectional shape of the main spacer and the sub-spacer, the diameter of the columnar spacer has become smaller in recent years, and the difference in cross-sectional shape is discriminated. Things have become very difficult.

  The present invention has been made in view of these points, and the object of the present invention is to more reliably generate low-temperature shock bubbles in the liquid crystal layer by allowing an appropriate amount of liquid crystal to be dropped. There is to try to prevent.

  In order to achieve the above object, a liquid crystal display device according to the present invention includes a first substrate, a second substrate disposed opposite to the first substrate and having a plurality of columnar spacers, and the first substrate. A liquid crystal layer provided between the substrate and the second substrate, wherein a display region is formed in the region where the liquid crystal layer is provided, wherein the columnar spacer has the tip at the first substrate. A first spacer for defining a distance between the first substrate and the second substrate by contacting the first substrate, and a second spacer having a height lower than the first spacer, and the display region includes the first spacer. 1st area | region where 1 spacer and 2nd spacer are mixed and arrange | positioned in a fixed ratio, and it has the 2nd area | region which has an area smaller than this 1st area | region and where only the said 1st spacer is arrange | positioned severally ing.

  The second area may be arranged in the center of the display area.

  A seal member for enclosing the liquid crystal layer is provided between the first substrate and the second substrate, and the seal member is formed in a ring shape when viewed from the normal direction of the surface of the second substrate. You may be comprised by one member made.

  The method for manufacturing a liquid crystal display device according to the present invention includes a first substrate, a second substrate disposed opposite to the first substrate and having a plurality of columnar spacers, the first substrate and the second substrate. A liquid crystal layer provided between the substrates, and a method of manufacturing a liquid crystal display device in which a display region is formed in a region where the liquid crystal layer is provided, the step of forming the first substrate, and a tip The plurality of columnar shapes having a first spacer that defines a distance between the first substrate and the second substrate by contacting the first substrate, and a second spacer having a height lower than the first spacer. The step of forming the second substrate by forming a spacer on the substrate, the step of calculating the drop amount of the liquid crystal by detecting the height of the columnar spacer on the second substrate, and the above calculation. The amount of liquid crystal dropped is transferred to the first substrate or A step of dropping onto the second substrate, and a step of bonding the first substrate and the second substrate through the liquid crystal, and in the step of forming the second substrate, the first spacer and the second spacer Are arranged in a fixed ratio, and a second region having a smaller area than the first region and a plurality of only the first spacers is arranged on the display region of the second substrate. In the step of calculating the dropping amount of the liquid crystal, the height of the first spacer is detected in the second region of the second substrate.

  In the step of forming the second substrate, the second region may be formed so as to be arranged at the center of the display region.

  Forming a seal member for enclosing the liquid crystal layer on the first substrate or the second substrate, and in the step of forming the seal member, the seal member is formed on the surface of the first substrate or the second substrate. You may make it form with one member which is ring shape seeing from the normal line direction.

-Action-
Next, the operation of the present invention will be described.

  In the liquid crystal display device, in the first region in the display region, the first spacer that defines the distance between the first substrate and the second substrate and the second spacer that is lower than the first spacer are mixed at a certain ratio. Therefore, the generation of low-temperature impact bubbles in the liquid crystal layer is suppressed.

  In the case of manufacturing a liquid crystal display device, it is possible to optically detect the height of the first spacer formed in the second region of the second substrate and calculate the liquid crystal dropping amount. At this time, since only the plurality of first spacers are arranged in the second region, there is no misjudgment with the second spacer, and the height of the first spacer is reliably detected. As a result, the amount of liquid crystal dropped can be calculated appropriately, and the liquid crystal layer can be formed with an appropriate amount of liquid crystal. As a result, generation of low-temperature shock bubbles in the liquid crystal layer can be prevented more reliably.

  Furthermore, if the second area is arranged in the center of the display area, even if the second area is very small compared to the first area, the second area can be easily identified. It becomes possible to calculate more easily and appropriately.

  In the case of manufacturing the liquid crystal display device, after forming the first substrate and the second substrate, liquid crystal is dropped on the first substrate or the second substrate, and the first substrate and the second substrate are passed through the liquid crystal. Bond the substrate. In the step of forming the second substrate, the first region in which the first spacer and the second spacer are mixed and the second region in which only a plurality of the first spacers are arranged are divided into the display region of the second substrate. To form. And before dripping the said liquid crystal, the dripping amount of a liquid crystal is calculated by detecting the height of a 1st spacer in the said 2nd area | region. As a result, as described above, it is possible to reliably detect the height of the first spacer and appropriately calculate the liquid crystal dropping amount.

  According to the present invention, the first region in which the first spacer and the second spacer are mixed and the second region in which only the first spacer is disposed are formed on the second substrate. By optically detecting the height of the first spacer formed in the second region, it is possible to reliably detect the height of the first spacer without making a mistake with the second spacer. it can. As a result, since the liquid crystal layer can be formed with an appropriate amount of liquid crystal by appropriately calculating the dropping amount of the liquid crystal, it is possible to more reliably prevent the generation of low-temperature shock bubbles in the liquid crystal layer.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

<< Embodiment of the Invention >>
1 to 4 show an embodiment of the present invention.

  FIG. 1 is a plan view schematically showing an overview of a liquid crystal display device 1 in the present embodiment. FIG. 2 is a plan view showing the first region 21 of the counter substrate 12 in the present embodiment. FIG. 3 is a plan view showing the second region 22 of the counter substrate 12 in the present embodiment. FIG. 4 is a cross-sectional view showing a schematic structure of the liquid crystal display device 1 in the present embodiment.

-Configuration of liquid crystal display device-
As shown in FIGS. 1 and 4, the liquid crystal display device 1 includes a TFT substrate 11 as a first substrate, a counter substrate 12 as a second substrate disposed to face the TFT substrate 11, and the counter substrate 12. And a liquid crystal layer 13 provided between the TFT substrates 11.

(Configuration of seal member and display area)
A sealing member 14 for enclosing the liquid crystal layer 13 is provided between the TFT substrate 11 and the counter substrate 12. As shown in FIG. 1, the seal member 14 is configured by a single member formed in a rectangular ring shape when viewed from the normal direction of the surface of the counter substrate 12.

  A display area 20 is formed in an area inside the seal member 14 provided with the liquid crystal layer 13. A non-display area 24 is formed in a frame shape around the outside of the display area 20. The liquid crystal layer is formed by a dropping injection method as will be described later. The shape of the seal member 14 is not limited to a rectangular ring shape, and may be another ring shape such as an oval shape.

(Configuration of TFT substrate)
The TFT substrate 11 is configured as a so-called active matrix substrate. As shown in FIG. 4, the TFT substrate 11 has a glass substrate 15 that is a transparent substrate. A plurality of wiring layers 16 such as gate wirings and source wirings made of a metal layer are formed on the glass substrate 15. The plurality of gate wirings are formed to extend in parallel to each other. The plurality of source wirings are formed in parallel to each other and arranged to be orthogonal to the gate wiring. As a result, the wiring layer 16 is formed in a lattice pattern on the TFT substrate 11. A plurality of pixels (not shown) are partitioned by the grid-like wiring layer 16.

  An interlayer insulating film 17 is formed on the glass substrate 15 so as to cover the wiring layer 16. A pixel electrode 18 for driving the liquid crystal layer 13 is formed on the surface of the interlayer insulating film 17. The pixel electrode 18 is made of a transparent electrode such as ITO (Indium Tin Oxide), for example, and is arranged for each of the pixels. Although not shown, each pixel is provided with a TFT (Thin-Film Transistor) as a switching element connected to the gate wiring and the source wiring. The TFT is covered with the interlayer insulating film 17 and connected to the pixel electrode 18 through a contact hole (not shown) formed in the interlayer insulating film 17.

(Configuration of counter substrate)
On the other hand, the counter substrate 12 has a glass substrate 25 that is a transparent substrate, as shown in FIG. On the glass substrate 25, as shown in FIGS. 2 and 4, a plurality of black matrices 26, which are light shielding films, are formed in a stripe shape, for example. The black matrix 26 is formed wider than other regions in a region where a columnar spacer 30 described later is formed. The black matrix 26 is formed of a metal film such as a chromium film.

  The glass substrate 25 is provided with a color filter layer 28 including a plurality of colored layers 27. The color filter layer 28 includes red (R), green (G), and blue (B) colored layers 27. The black matrix 26 is arranged between the colored layers 27 of the respective colors. As a result, the boundary between the colored layers 27 is shielded by the black matrix 26.

  A common electrode 29 made of a transparent electrode such as ITO is formed on the surface of the color filter layer 28 over the entire display area 20. That is, the common electrode 29 is opposed to each pixel electrode 18 formed on the TFT substrate 11 in common.

  A plurality of columnar spacers (photo spacers) 30 are formed on the surface of the common electrode 29 in the counter substrate 12 so as to overlap the black matrix 26. The plurality of columnar spacers 30 are arranged in a matrix in the display area 20 and include a first spacer (main photo spacer) 31 and a second spacer (sub photo spacer) 32 having a height lower than that of the first spacer 31. Have.

  The first spacer 31 defines the distance between the TFT substrate 11 and the counter substrate 12 (that is, the thickness of the liquid crystal layer 13) when the tip contacts the TFT substrate 11. On the other hand, the second spacer 32 is provided with a predetermined interval between its tip and the TFT substrate 11.

(First region and second region)
As shown in FIG. 2, the display area 20 includes the first area 21 in which the first spacers 31 and the second spacers 32 are mixedly mixed at a constant ratio, and the first area 21 as shown in FIG. The second region 22 has a smaller area than the region 21 and in which only a plurality of first spacers 31 are arranged. As shown in FIG. 1, the second area is a rectangular area arranged in the center of the display area 20. In the first region 21, for example, one column of second spacers 32 and one column of first spacers 31 are arranged alternately in the row direction.

-Operation of liquid crystal display devices-
In the liquid crystal display device 1, the signal voltage is supplied from the source wiring to the pixel electrode 18 through the TFT in a state where the scanning voltage is applied to the TFT through the gate wiring, so that the liquid crystal layer 13 is formed for each pixel. It is driven to display a desired image.

  Further, the thickness of the liquid crystal layer 13 is defined by the first spacers 31 provided in the first region 21 and the second region 22. For example, when the counter substrate 12 is pressed by the user, the counter substrate 12 curved toward the liquid crystal layer 13 is supported by the second spacer 32, so that the strength of the liquid crystal display device 1 is appropriately maintained.

-Manufacturing method-
Next, a method for manufacturing the liquid crystal display device 1 will be described.

  First, in the first step, the TFT substrate 11 is formed. The TFT substrate 11 forms a wiring layer 16 such as a gate wiring by patterning a metal film formed on the glass substrate 15 by photolithography. Further, after forming a TFT (not shown), the TFT is covered with an interlayer insulating film 17, and contact holes (not shown) and a plurality of pixel electrodes 18 made of ITO are formed in the interlayer insulating film 17. Then, the pixel electrode 18 is connected to the TFT through the contact hole.

  In the second step, the counter substrate 12 is formed. Either the first step or the second step may be performed first. That is, in the second step, a stripe-shaped black matrix 26 is formed by sputtering a metal film such as a chromium film on the glass substrate 25 and patterning it by photolithography. Thereafter, a color filter layer 28 is formed by forming colored layers of a plurality of colors of R, G, and B so as to cover the black matrix 26. Thereafter, an ITO layer is uniformly formed so as to cover the color filter layer 28 to form a common electrode 29.

  Next, the first spacer 31 and the second spacer 32 are formed on the surface of the common electrode 29 on the substrate. The first spacer 31 and the second spacer 32 can be collectively formed by halftone exposure of a photosensitive resin uniformly applied on the common electrode 29. At this time, a first region 21 in which the first spacer 31 and the second spacer 32 are mixedly arranged at a constant ratio, and a plurality of the first spacers 31 having a smaller area than the first region 21 are disposed. The second region 22 is formed in the display region 20 of the counter substrate 12. The second area 22 is formed in the center of the display area 20. In this way, the counter substrate 12 is formed.

  Next, a third step is performed, and a sealing member 14 for sealing the liquid crystal layer 13 between the substrates is formed on the TFT substrate 11 or the counter substrate 12. In the third step, for example, the sealing member 14 made of a resin that is cured by heat and ultraviolet rays is formed by a single member that has a ring shape when viewed from the normal direction of the surface of the TFT substrate 11 or the counter substrate 12.

  Next, a fourth step is performed to detect the height of the columnar spacers 30 on the counter substrate 12, thereby calculating the liquid crystal dripping amount. In the fourth step, the height of the first spacer 31 is detected in the second region 22 of the counter substrate 12 using an optical measuring device.

  Thereafter, the fifth step is performed, and the calculated amount of liquid crystal is dropped onto the TFT substrate 11 or the counter substrate 12. The liquid crystal is preferably dropped inside the seal member 14 with respect to the substrate on which the ring-shaped seal member 14 is formed, among the TFT substrate 11 and the counter substrate 12.

  Next, a sixth step is performed, and the TFT substrate 11 and the counter substrate 12 are bonded to each other via the dropped liquid crystal and the seal member 14. After this bonding, the seal member 14 is completely cured. Thus, the liquid crystal display device 1 is manufactured.

-Effect of the embodiment-
Therefore, according to this embodiment, the counter substrate 12 includes the first region 21 in which the first spacers 31 and the second spacers 32 are mixed and the second region 22 in which only a plurality of the first spacers 31 are disposed. Since the height of the first spacer 31 formed in the second region 22 is optically detected, the first spacer 31 is not erroneously discriminated from the second spacer 32. The height of 31 can be reliably detected. As a result, since the liquid crystal layer 13 can be formed with an appropriate amount of liquid crystal by appropriately calculating the amount of liquid crystal dripped, the generation of low-temperature shock bubbles in the liquid crystal layer 13 can be more reliably prevented.

  Furthermore, since the second area 22 is arranged in the center of the display area 20, even if the second area 22 is a very small area compared to the first area 21, it is easy to specify the second area 22. Therefore, it becomes possible to calculate the liquid crystal dropping amount more easily and appropriately.

  In addition, since the first spacer 31 and the second spacer 32 are mixed in the wider first region 21, the thickness of the liquid crystal layer 13 that is a gap between the substrates can be appropriately maintained.

<< Other Embodiments >>
In the above embodiment, the example in which the second region 22 is arranged at the center of the display region 20 has been described. .

  Further, the first spacers 31 and the second spacers 32 in the first region 21 are not limited to the above arrangement pattern, and may be arranged in other patterns as long as they are mixed.

  As described above, the present invention is useful for a liquid crystal display device having columnar spacers and a method for manufacturing the same.

FIG. 1 is a plan view schematically showing an overview of a liquid crystal display device according to the present embodiment. FIG. 2 is a plan view showing a first region of the counter substrate in the present embodiment. FIG. 3 is a plan view showing a second region of the counter substrate in the present embodiment. FIG. 4 is a cross-sectional view showing a schematic structure of the liquid crystal display device according to the present embodiment. FIG. 5 is a plan view showing a conventional counter substrate. FIG. 6 is an enlarged cross-sectional view showing a part of a conventional counter substrate.

Explanation of symbols

1 Liquid crystal display device
11 TFT substrate (first substrate)
12 Counter substrate (second substrate)
13 Liquid crystal layer
14 Sealing member
20 display area
21 First area
22 Second area
30 Columnar spacer
31 1st spacer
32 Second spacer

Claims (6)

A first substrate;
A second substrate disposed opposite to the first substrate and having a plurality of columnar spacers formed thereon;
A liquid crystal layer provided between the first substrate and the second substrate,
A liquid crystal display device in which a display region is formed in a region where the liquid crystal layer is provided,
The columnar spacer includes a first spacer that defines a distance between the first substrate and the second substrate by contacting a tip of the columnar spacer to the first substrate; a second spacer having a height lower than the first spacer; Have
The display region has a first region in which the first spacer and the second spacer are mixedly arranged at a certain ratio, and an area smaller than the first region and a plurality of the first spacers are disposed. A liquid crystal display device comprising: a second region. The liquid crystal display device according to claim 1.
The liquid crystal display device, wherein the second region is arranged in the center of the display region. The liquid crystal display device according to claim 1.
A sealing member for enclosing the liquid crystal layer is provided between the first substrate and the second substrate,
The liquid crystal display device, wherein the seal member is constituted by a single member formed in a ring shape when viewed from the normal direction of the surface of the second substrate. A first substrate; a second substrate disposed opposite to the first substrate and having a plurality of columnar spacers; and a liquid crystal layer provided between the first substrate and the second substrate, A method of manufacturing a liquid crystal display device in which a display region is formed in a region where a liquid crystal layer is provided,
Forming the first substrate;
The plurality of first spacers having a first spacer that defines a distance between the first substrate and the second substrate by having a tip contacting the first substrate, and a second spacer having a height lower than the first spacer. Forming the second substrate by forming columnar spacers on the substrate;
Calculating a liquid crystal dropping amount by detecting a height of the columnar spacer in the second substrate;
Dropping the calculated amount of liquid crystal onto the first substrate or the second substrate;
Bonding the first substrate and the second substrate through the liquid crystal,
In the step of forming the second substrate, the first region has a first area where the first spacer and the second spacer are mixed in a certain ratio, and has an area smaller than the first region and only the first spacer. Are formed in the display area of the second substrate,
The liquid crystal display device manufacturing method, wherein, in the step of calculating the liquid crystal dropping amount, the height of the first spacer is detected in the second region of the second substrate. In the manufacturing method of the liquid crystal display device of Claim 1,
In the step of forming the second substrate, the second region is formed so as to be arranged at the center of the display region. In the manufacturing method of the liquid crystal display device of Claim 1,
Forming a sealing member for enclosing the liquid crystal layer on the first substrate or the second substrate;
In the step of forming the sealing member, the sealing member is formed by a single member that has a ring shape when viewed from the normal direction of the surface of the first substrate or the second substrate. Method.

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