JP3638346B2 - Liquid crystal display element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display element, and more particularly to an improvement related to a columnar spacer introduced to keep a distance between two substrates sealing liquid crystal in the liquid crystal display element constant.
[0002]
[Prior art]
At present, a liquid crystal display element that is generally used has two glass substrates having electrodes facing each other, and the periphery of the two substrates is fixed with an adhesive except for a liquid crystal sealing port. The liquid crystal is sandwiched between the substrates, and the liquid crystal sealing port is sealed with a sealant. As a spacer for keeping the distance between the two substrates constant, plastic beads having a uniform particle diameter are scattered between the substrates.
[0003]
A color filter with an RGB colored layer is formed on one of two glass substrates constituting a liquid crystal display element for color display. For example, in a color-type dot matrix liquid crystal display element of simple matrix driving, under a Y substrate having a Y electrode patterned in a strip shape in the horizontal (Y) direction and an X electrode patterned in a strip shape in the vertical (X) direction. An X substrate having a colored layer is disposed so as to face each other so that the Y electrode and the X electrode are substantially orthogonal to each other, and the liquid crystal composition is sandwiched therebetween. As a display method of the liquid crystal display element, for example, a TN (Twisted Nematic) type, STN (Super Twisted Nematic) type, GH (Guest Host) type, ECB (Electrically Controlled Birefringence) type, ferroelectric liquid crystal, or the like is used. As the sealant, for example, a heat or ultraviolet curable acrylic or epoxy adhesive is used.
[0004]
In a color type active matrix driving liquid crystal display element, a switching element, for example, a thin film transistor (TFT) using amorphous silicon (a-Si) as a semiconductor layer, a pixel electrode connected thereto, a signal line electrode, and a gate electrode are formed. An electrode transition material (transfer) that has a TFT array substrate, which is an active matrix substrate, and a counter electrode disposed opposite to the TFT matrix substrate, and that forms an RGB color filter on the counter substrate and applies a voltage from the active matrix substrate to the counter substrate As described above, a silver paste or the like is disposed in the periphery of the screen, and two substrates are electrically connected by this electrode transition material, and a liquid crystal composition is sandwiched between the two sheets. Further, a polarizing plate is sandwiched between both sides of the two substrates, and the polarizing plate light is used as a display shutter when displaying a color image.
[0005]
[Problems to be solved by the invention]
In these liquid crystal display elements, the orientation of the liquid crystal around the spacers scattered between the two substrates is disturbed, and light leaks from the peripheral part of the spacer and the contrast tends to decrease. In addition, it is difficult to uniformly disperse the spacers. If the spacers are non-uniformly arranged in the process of dispersing the spacers on the substrate, display defects are caused and the product yield is reduced.
[0006]
As countermeasures, for example, Japanese Patent Application No. 7-212192 proposed that a spacer is formed by overlapping a colored layer of a color filter at a position other than the display region, or that a columnar spacer is formed of a photoresist or the like.
[0007]
However, after that, two main points to be improved were found. It relates to the alignment treatment by rubbing and the mechanical strength of the columnar spacer.
[0008]
First, when a rubbing process is performed in which an alignment film is formed after forming the columnar spacers and a large number of fine grooves are formed in one direction with the rubbing cloth on the entire alignment film, the rubbing cloth hits the columnar spacers. Since the columnar spacer has a quadrangular or round shape, a relatively large stress (friction resistance) is applied to the rubbing cloth, which causes the rubbing cloth to bend or damage the rubbing cloth. If such a rubbing cloth having an abnormality on the hair is continuously used, a non-uniform rubbing process is performed, which causes a display defect.
[0009]
In addition, the bristles of the rubbing cloth are temporarily bent by the columnar spacer, so that a non-uniform fine groove group is partially formed until the bristles of the rubbing cloth return to the original, and in the vicinity of the columnar spacer. Partial rubbing failure occurs and causes display failure.
[0010]
The columnar spacer is directly formed on the substrate using a resin or a photosensitive resin. Since the resin and the photosensitive resin are polymer materials, the mechanical strength such as hardness and adhesion is not sufficient, and the spacer is easily peeled off and deformed. For this reason, there arises a problem that the reliability of the liquid crystal display device is lowered.
[0011]
Further, the distance between the substrates is as very small as about 2 μm, and the columnar spacers hinder the inflow of the liquid crystal when the liquid crystal is injected. In particular, the ferroelectric liquid crystal makes it difficult to inject liquid crystal.
[0012]
Therefore, an object of the present invention is to prevent disorder of orientation caused by rubbing treatment by introducing columnar spacers and to prevent display performance from being deteriorated.
[0013]
Another object of the present invention is to ensure the mechanical strength of a columnar spacer formed of resin or the like.
[0014]
Another object of the present invention is to provide a liquid crystal display element that facilitates the injection of liquid crystal into the liquid crystal display element.
[0017]
According to a third aspect of the present invention, there is provided a liquid crystal display element comprising: a light-shielding layer having a plurality of pixel regions opened in a matrix or stripe between two insulating substrates that are arranged opposite to each other and sandwich a liquid crystal therebetween; A liquid crystal display having at least a color filter disposed in the opened portion, a spacer that secures a gap between the two insulating substrates, and an alignment film that is subjected to an alignment treatment that gives the liquid crystal alignment in a specific direction. The element, the spacer is located in the vicinity of the opening on the light-shielding layer, and is disposed at a position not adjacent to the green color filter on the downstream side in the specific direction from this position, and the alignment film is aligned with the alignment film. The misalignment region generated by the processing is not formed in the green color filter region in the region where the color filter is arranged, but the red color filter region. And wherein the and / or formed on the blue color filter regions.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, some embodiments of the present invention will be described with reference to the drawings.
[0022]
First, in the first invention for solving the problem in the rubbing process, in the rubbing process performed in one direction, the surface of the columnar spacer against which the hair of the rubbing cloth hits the hair of the rubbing cloth (resistance) ) To reduce the shape.
[0023]
In other words, a taper is formed on the surface of the columnar spacer that the rubbing cloth touches and reduces resistance to the hair tips. In addition, the width (the width of the cross section of the columnar spacer in a plane parallel to the substrate) in the direction perpendicular to the rubbing direction of the columnar spacer portion (front end) where the bristles of the rubbing cloth first contact is determined from this portion. In the rubbing direction, the shape is narrower than the same width in the rear portion (center portion and rear end portion). Pyramids, cones, truncated pyramids, truncated cones, etc. fall into this category. As will be described later, when the mechanical strength of the columnar spacer is further taken into consideration, it is preferable that the cross-sectional shape of the spacer by a plane parallel to the substrate serving as the spacer be an ellipse whose major axis is the rubbing direction.
[0024]
For example, the columnar spacer has a substantially isosceles triangular shape and a rhombus shape. By setting the rubbing start side of the columnar spacer to the apex of a substantially isosceles triangle or rhombus, the bristle foot of the rubbing cloth is reduced so that the bristle smoothly wraps around the side of the spacer, and the bristle foot receives Reduce stress. Furthermore, the stress on the rubbing cloth can be further reduced by forming the spacer shape into a tapered shape so that the height of the spacer is lower on the rubbing start side.
[0025]
As a result, it becomes possible to prevent the occurrence of display defects due to the bending of the bristle feet of the rubbing cloth, and a highly reliable liquid crystal display element with high display performance can be obtained.
[0026]
FIG. 1 is a sectional view of an active matrix liquid crystal device according to an embodiment of the present invention. In this liquid crystal display element, an active matrix substrate 1 and a counter substrate 2 are arranged to face each other, and a liquid crystal composition 28 is sealed between them.
[0027]
FIG. 2 is a cross-sectional view showing the configuration of the active matrix substrate 1 in detail. The active matrix substrate has a structure in which the TFT portion is called an inverted stagger type. A gate electrode 14 is disposed in the TFT portion on the main surface side of the glass substrate 11, and a scanning line 1 f is disposed in the wiring portion, and an insulating film 1 a is deposited thereon. A semiconductor film 1b made of amorphous silicon is formed on the insulating film 1a and above the gate electrode 14, and a source 1c and a drain 1d are formed in the center of the semiconductor film 1b so as to straddle the semiconductor film 1b and the insulating film 1a. Are formed so as to face each other with a distance of. A signal line 13 is connected to the drain 1d, and a pixel electrode 15 is connected to the source 1c. A protective film 1e is formed on the entire surface of the TFT portion and the wiring portion, and an alignment film 16 is formed on the entire surface of the pixel portion. In FIG. 1, the same elements as those in FIG. 2 are denoted by the same reference numerals, but in order to make the invention easier to understand, some shapes are changed.
[0028]
Referring to FIG. 1 again, the upper counter substrate 2 has red, green, and blue color filters 23, 24, and 25 formed on the glass substrate 21 in accordance with the pixel positions. Further, these color filter materials are laminated to form a columnar spacer 30. The spacer 30 is made of resin, photoresist or the like. A transparent electrode film 26 and an alignment film 27 are deposited on the entire surface.
[0029]
The two substrates are opposed to each other, and the spacer 30 of the counter substrate 2 is brought into contact with a TFT portion or a wiring portion, which is a light shielding region of the active matrix substrate 1. As can be seen from FIG. 2, there are two insulating layers on the scanning line, which is the lowermost layer, and even if the spacers 30 are in contact with each other, it is very unlikely that defects such as short circuits occur due to the loss of insulation. . Of course, as shown in FIG. In this case, since the crest portion of the substrate is used, the film thickness (height) of the spacer 30 can be formed relatively thin. A liquid crystal composition 28 is filled and sealed between both substrates.
[0030]
FIG. 3 shows an example of the shape of the columnar spacer 30. 4A is a perspective view of the columnar spacer 30, and FIG. 4B is a side view. In this example, the columnar spacer 30 is formed in a triangular pyramid, and in the rubbing direction, the portion where the bottom surface is the apex angle or the apex (the top portion) is first the fur feet of the rubbing cloth so as to divide the rubbing feet of the rubbing cloth with less resistance. Is considered to hit. In addition, as shown in FIG. 5B, the columnar spacer 30 has a tapered shape so that the height gradually increases, reducing frictional resistance and catching, and damaging the hair of the rubbing cloth. Considered not to give. In FIG. 3, the bottom surface of the spacer is on the substrate 21 side (the same applies to other shapes of spacers described later).
[0031]
Next, a method for manufacturing such a liquid crystal display element will be described.
[0032]
First, similar to the process of forming a known thin film transistor (TFT), film formation and patterning are repeated on a glass substrate (for example, # 7059, manufactured by Corning) 11 having a thickness of 1.1 mm, and made of amorphous silicon. A thin film transistor 12 and a pixel electrode 15 made of ITO are arranged in a matrix, and a plurality of signal lines 13 for applying a predetermined voltage to each pixel electrode 12 through the transistor 12 and a plurality of gate lines 14 for controlling conduction of the transistor 12 are provided. Are formed in a lattice shape along a plurality of pixel electrodes arranged in a matrix to form an array substrate. Thereafter, AL-1051 (manufactured by Nippon Synthetic Rubber Co., Ltd.) is applied to the entire surface as an alignment film material by 500 angstroms, and a rubbing process is performed to form the alignment film 16.
[0033]
Next, a photosensitive black resin CK-2000 (manufactured by Fuji Hunt Technology Co., Ltd.) was applied onto a counter substrate made of a Corning Corporation # 7059 glass substrate 21 having a thickness of 1.1 mm using a spinner. After drying at 90 ° C. for 10 minutes, using a photomask having a light shielding layer pattern, the film was exposed at a wavelength of 365 nm with an exposure amount of 300 mJ / cm 2 and then developed with an alkaline aqueous solution having a pH of 11.5, followed by 200 ° C. for 60 minutes. The light shielding layer 22 having a thickness of 2.0 μm is formed by baking.
[0034]
A photo for forming a red filter in which a UV curable acrylic resin resist CR-2000 (produced by Fuji Hunt Technology Co., Ltd.) in which a red pigment is dispersed is applied to the entire surface with a spinner, and light is irradiated on the portion to be colored red. The film is irradiated with 100 mJ / cm @ 2 at a wavelength of 365 nm through a mask and developed with a 1% aqueous solution of KOH for 10 seconds to form a red colored layer 23.
[0035]
By repeating the same process, green and blue colored layers 24 and 25 are formed and finally baked at 230 ° C. for 1 hour. Here, CG-2000 (Fuji Hunt Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (Fuji Hunt Technology Co., Ltd.) was used as the blue coloring material. At this time, the film thicknesses of R, G, and B were each 1.5 μm.
[0036]
Next, an ultraviolet curable acrylic resin resist containing no pigment is applied on the entire surface with a spinner, and 100 mJ at a wavelength of 365 nm is passed through a photomask that irradiates light to a desired position on the light shielding layer where a spacer is to be formed. / Cm @ 2 irradiation and development with a 1% aqueous solution of KOH for 30 seconds to form spacers 30.
[0037]
The film thickness at this time was 4 μm, and the development was strengthened so as to form a substantially isosceles triangle. Thus, a substantially triangular spacer 30 was obtained. Thereafter, an ITO film was formed as a transparent electrode 26 by a sputtering method to a thickness of 1500 angstroms, a similar alignment film material was formed thereon, and then a rubbing process was performed to form an alignment film 27. In addition, the adhesive force of the spacer 30 is obtained by forming the spacer 30 before forming the transparent electrode 26.
[0038]
Thereafter, an adhesive is printed along the periphery of the alignment film 27 on the glass substrate 21 except for an injection port (not shown), and an electrode transition material for applying a voltage from the active matrix substrate to the counter electrode is adhered. It was formed on the electrode transition electrode around the agent. Next, the substrates 11 and 21 were placed so that the alignment films 27 and 16 face each other and the rubbing directions thereof were 90 degrees, and the adhesive was heated to cure and bonded. Next, a liquid crystal composition 29 is injected from the inlet as a liquid crystal composition 29 by adding 0.1 wt% of S811 to ZLI-1565 (manufactured by E. Merck), and then the inlet is sealed with an ultraviolet curable resin. did.
[0039]
The color display type active matrix liquid crystal display element thus formed has less stress on the rubbing cloth, and the hair of the rubbing cloth does not bend, thus preventing display defects due to rubbing and having high display performance and reliability. It became possible to obtain a liquid crystal display element having a property.
[0040]
FIG. 5 shows another embodiment of the present invention. Parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
FIG. 6 is a schematic view of the spacer 30 according to this embodiment.
[0041]
In this embodiment, as shown in FIG. 6, the spacer 30 has a shape in which a cross-sectional shape by a plane including this axis is a rhombus if the rubbing direction is a coordinate axis. The shape of the spacer 30 is also such that the apex angle is at the position where the hair of the rubbing cloth first hits and has a tapered surface, so there is little stress on the rubbing cloth, and the hair of the rubbing cloth may be bent forcibly. Therefore, display defects caused by rubbing can be prevented. Other configurations are the same as those of the embodiment shown in FIG.
[0042]
A method of manufacturing the liquid crystal display element according to this embodiment will be described.
[0043]
Similar to a known TFT forming process, film formation and patterning are repeated on a # 7059 glass substrate 11 made by Corning having a thickness of 1.1 mm, and a thin film transistor 12 made of amorphous silicon, a signal line 13, and a gate line. 14. An array substrate on which display electrodes 15 made of ITO are formed is formed. Thereafter, AL-1051 (manufactured by Nippon Synthetic Rubber Co., Ltd.) as an alignment film material was applied to the entire surface by 500 angstroms and rubbed to form an alignment film 16.
[0044]
Next, a photosensitive black resin CK-2000 (manufactured by Fuji Hunt Technology Co., Ltd.) was applied onto a counter substrate made of a Corning Corporation # 7059 glass substrate 21 having a thickness of 1.1 mm using a spinner. After drying at 90 ° C. for 10 minutes, using a photomask having a predetermined pattern shape, exposing at a wavelength of 365 nm with an exposure amount of 300 mJ / cm 2, developing with an alkaline aqueous solution having a pH of 11.5, 200 ° C., 60 minutes The light shielding layer 22 having a thickness of 2.0 μm is formed by baking. Next, an ultraviolet curable acrylic resin resist CR-2000 (manufactured by Fuji Hunt Technology Co., Ltd.) in which a red pigment is dispersed is applied over the entire surface with a spinner, and a photomask in which light is irradiated on the portion where red is to be colored. The film is irradiated with 100 mJ / cm @ 2 at a wavelength of 365 nm and developed with a 1% aqueous solution of KOH for 10 seconds to form a red colored layer 23. Similarly, green and blue colored layers 24 and 25 are repeatedly formed and finally fired at 230 ° C. for 1 hour. Here, CG-2000 (Fuji Hunt Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (Fuji Hunt Technology Co., Ltd.) was used as the blue coloring material. At this time, the film thicknesses of R, G, and B were each 1.5 μm.
[0045]
Next, an ultraviolet curable acrylic resin resist containing no pigment was applied on the entire surface with a spinner to the same thickness. In the first etching, 100 mJ / cm @ 2 was irradiated at a wavelength of 365 nm through a photomask that irradiates a desired position on the light shielding layer where the spacer 30 is to be formed, and developed with a 1% aqueous solution of KOH for 30 seconds. . Further, the second etching was performed so that the spacer 30 has a reverse tapered shape with a large amount of side etching. The film thickness at this time was 4 μm, and development was strengthened so as to obtain a strong taper shape. Thus, a diamond-shaped spacer 30 was obtained.
[0046]
Thereafter, an ITO film was formed as the transparent electrode 26 by a 1500 angstrom sputtering method, a similar alignment film material was formed thereon, and then a rubbing process was performed to form an alignment film 27.
[0047]
Similar to the embodiment shown in FIG. 1, the spacer adhesion can be obtained by forming the spacer 30 before the transparent electrode 26 is formed.
[0048]
Thereafter, an adhesive is printed along the periphery of the alignment film 27 on the glass substrate 21 except for an injection port (not shown), and an electrode transition material for applying a voltage from the active matrix substrate to the counter electrode is adhered. It was formed on the electrode transition electrode around the agent. Next, the substrates 11 and 21 were arranged so that the alignment films 27 and 16 face each other and the rubbing directions thereof were 90 degrees, and the adhesive was heated and cured to be bonded. Next, a liquid crystal composition 29 is injected from the inlet as a liquid crystal composition 29 by adding 0.1 wt% of S811 to ZLI-1565 (manufactured by E. Merck), and then the inlet is sealed with an ultraviolet curable resin. did.
[0049]
The color display type active matrix liquid crystal display element thus formed has less stress on the rubbing cloth, and the hair of the rubbing cloth does not bend, so it can prevent display defects due to rubbing and has high display performance and reliability. A liquid crystal display element could be obtained.
[0050]
FIG. 6 shows another embodiment of the present invention. Parts corresponding to those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
FIG. 7 is a schematic view of the spacer 30 according to this embodiment.
[0051]
In this embodiment, as shown in FIG. 7, the spacer 30 has a shape obtained by shaving the upper part of the triangular prism so that the cross section becomes a triangle, and if the rubbing direction is a coordinate axis, the cross section is a plane including this axis. The shape is a trapezoidal shape. The shape of the spacer 30 is also such that the apex angle is at the position where the hair of the rubbing cloth first hits and has a tapered surface, so that the stress on the rubbing cloth is less and the hair of the rubbing cloth may be bent forcibly. Therefore, display defects caused by rubbing can be prevented. Other configurations are the same as those of the embodiment shown in FIG.
[0052]
A method of manufacturing the liquid crystal display element according to this embodiment will be described.
[0053]
Similar to the process of forming a normal TFT, film formation and patterning are repeated on a # 7059 glass substrate 11 made by Corning having a thickness of 1.1 mm, and the thin film transistor 12 made of amorphous silicon, the signal line 13, the gate line 14, An array substrate on which the display electrodes 15 made of ITO are formed is formed. Thereafter, AL-1051 (manufactured by Nippon Synthetic Rubber Co., Ltd.) is applied over the entire surface as an alignment film material, and a rubbing process is performed to form the alignment film 16.
[0054]
Next, a photosensitive black resin CK-2000 (manufactured by Fuji Hunt Technology Co., Ltd.) was applied onto a counter substrate made of a Corning Corporation # 7059 glass substrate 21 having a thickness of 1.1 mm using a spinner. After drying at 90 ° C. for 10 minutes, using a photomask having a predetermined pattern shape, exposing at a wavelength of 365 nm with an exposure amount of 300 mJ / cm 2, developing with an alkaline aqueous solution having a pH of 11.5, 200 ° C., 60 minutes The light shielding layer 22 having a thickness of 2.0 μm is formed by baking. Next, an ultraviolet curable acrylic resin resist CR-2000 (manufactured by Fuji Hunt Technology Co., Ltd.) in which a red pigment is dispersed is applied over the entire surface with a spinner, and a photomask in which light is irradiated on a portion to be colored red The film is irradiated with 100 mJ / cm @ 2 at a wavelength of 365 nm and developed with a 1% aqueous solution of KOH for 10 seconds to form a red colored layer 23. Similarly, green and blue colored layers 24 and 25 are repeatedly formed and finally fired at 230 ° C. for 1 hour. Here, CG-2000 (Fuji Hunt Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (Fuji Hunt Technology Co., Ltd.) was used as the blue coloring material. At this time, the film thicknesses of R, G, and B were each 1.5 μm.
[0055]
Next, an ultraviolet curable acrylic resin resist containing no pigment is applied on the entire surface with a spinner, and 100 mJ at a wavelength of 365 nm is passed through a photomask that irradiates light to a desired position on the light shielding layer where a spacer is to be formed. / Cm @ 2 and developed with a 1% aqueous solution of KOH for 30 seconds. The film thickness at this time is 4 μm.
[0056]
Next, using a gradation mask, 100 mJ / cm @ 2 was similarly irradiated at a wavelength of 365 nm, and development was performed with a 1% aqueous solution of KOH for 30 seconds, thereby forming a spacer 30 having a height reduced by one piece.
[0057]
Thereafter, an ITO film was formed as the transparent electrode 26 by 1500 angstrom sputtering, a similar alignment film material was formed thereon, and then a rubbing process was performed to form an alignment film 27.
In addition, the adhesive force of a spacer is acquired by forming a spacer before transparent electrode formation.
[0058]
An adhesive is printed along the periphery of the alignment film 27 on the substrate 21 except for an injection port (not shown), and an electrode transition material for applying a voltage from the active matrix substrate to the counter electrode is formed around the adhesive. It formed on the electrode transition electrode.
[0059]
Next, the substrates 11 and 21 were arranged so that the alignment films 27 and 16 face each other and the rubbing directions thereof were 90 degrees, and the adhesive was heated and cured to be bonded. Next, a liquid crystal composition 29 is injected from the inlet as a liquid crystal composition 29 by adding 0.1 wt% of S811 to ZLI-1565 (manufactured by E. Merck), and then the inlet is sealed with an ultraviolet curable resin. did.
[0060]
The color display type active matrix liquid crystal display device thus formed has less stress on the rubbing cloth than in Examples 1 and 2, and the hair of the rubbing cloth does not bend. A liquid crystal display element with high performance and reliability could be obtained.
[0061]
The coloring order described in the embodiment of the present invention is an example, and the present invention is not limited to this.
[0062]
FIG. 8 shows an example in which the spacers 30 having a shape according to the present invention are aligned on the rubbing direction and arranged on the substrate 21. As described above, when the spacers are arranged in the rubbing direction and arranged, the resistance received by the hair of the rubbing cloth is reduced as compared with the case where the spacers are arranged without considering the rubbing direction. As a result, it is possible to extend the life of the rubbing cloth and reduce the defects of the rubbing process.
[0063]
As described above, the stress on the rubbing cloth is reduced by setting the shape of the columnar spacer to be a substantially isosceles triangle shape or a rhombus shape and setting the rubbing start side to be a vertex of a substantially isosceles triangle shape or a rhombus shape. Furthermore, the stress on the rubbing cloth can be further reduced by forming the spacer so that the rubbing start side is lowered. Further, by aligning the spacers thus formed in the rubbing direction, it is possible to reduce the resistance received by the rubbing cloth as a whole.
[0064]
Next, an embodiment of the second invention will be described with reference to the drawings.
[0065]
First, according to the second aspect of the invention, the spacer is arranged at a position where the misalignment region starting from the spacer does not reach the inside of the pixel, which occurs when the bristle of the rubbing cloth hits the spacer and disturbs the fine groove. Therefore, it is possible to prevent display quality from being deteriorated.
[0066]
Also, focusing on human visual characteristics, when comparing the three primary colors of light, red, blue, and green, if the poorly aligned region does not occur as much as possible in the green pixel region with relatively good eye sensitivity, Even if a misalignment region is somewhat generated in the red pixel region or the blue pixel region, or both the red pixel region and the blue pixel region, the visual characteristics are not conspicuous. Therefore, it is possible to suppress the deterioration of display quality as much as possible by determining the arrangement of the spacers so as not to be adjacent to the blue pixel region.
[0067]
In this case, since it is not necessary to use a special shape for the spacer, for example, the spacer is the same as the color filter which is a constituent material of the color liquid crystal display device as proposed in Japanese Patent Application No. 7-212192. By forming the material at the same time, the spacer can be arranged without increasing the number of steps.
[0068]
FIG. 9 is a cross-sectional view of a liquid crystal display element for explaining the second invention. In FIG. 9, parts corresponding to those in FIG. In this liquid crystal display element, the spacer 30 is formed in a substantially cylindrical shape by laminating a colored layer (red) 23, a colored layer (green) 24, and a colored layer (blue) 25. For this reason, unlike the example shown in FIG. 1, the process of forming the spacer 30 separately is not required. In this embodiment, in particular, the arrangement location of the spacer 30 is devised and arranged in the light shielding region of the TFT.
[0069]
FIG. 10 is a diagram schematically illustrating the relationship between the location of the spacers 30 and the poor alignment region 41 of the liquid crystal display element shown in FIG. As can be seen from the figure, since the hair of the rubbing cloth is disturbed by the spacer 3 of the counter substrate 21, uneven alignment 41 starting from the spacer 30 occurs on the downstream side in the rubbing direction. Here, the rubbing direction is set to a direction of 45 degrees with respect to the vertical or horizontal direction of the liquid crystal display element in order to make the visual field-angle display characteristics in the left-right direction symmetrical. By arranging the spacer 30 on the upstream side in the rubbing direction of the TFT light shielding region 31, it is possible to use the TFT light shielding region 31 and the light shielding layer 22 to accommodate the alignment unevenness 41 in a portion that does not affect the pixel. . As a result, the influence of uneven alignment is removed from the image.
[0070]
A method of manufacturing the liquid crystal display element according to this embodiment will be described.
First, the counter substrate 21 was produced as follows. A photosensitive black resin is applied onto the glass substrate 21 using a spinner, dried at 90 ° C. for 10 minutes, and then irradiated with ultraviolet rays through a photomask having a pattern shape with a width of the light shielding layer 5 of 30 (μm). After irradiation with an exposure dose of 300 mJ / cm @ 2, development is performed with an alkaline aqueous solution at pH = 11.5, and baking is performed at 200 DEG C. for 60 minutes to form a light shielding layer 22 having a thickness of 2.0 (.mu.m).
[0071]
A photosensitive resist CR-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) in which a red pigment is dispersed is applied over the entire surface using a spinner, dried at 90 ° C. for 10 minutes, and then alignment unevenness 41 starting from the spacer 30 is obtained. However, the exposure amount is 100 mJ / cm @ 2 through a photomask in which ultraviolet rays are irradiated only on the portion where the red colored layer is formed, including the formation of the spacer 30 at a position where it is masked by the light shielding region 41 of the TFT 12. It exposed so that it might become. Next, development was carried out with a 1 wt% potassium hydroxide aqueous solution for 20 seconds, followed by baking at 200 ° C. for 60 minutes to form a red colored layer.
[0072]
Similarly, the green and blue colored layers are repeatedly formed, including the formation of spacers, so that the color filter 4 having a thickness of 1.5 (μm) and the light shielding layer 5 are colored in three colors. A spacer 30 in which the layers were superimposed was obtained. Here, CG-2000 (Fuji Hunt Electronics Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (Fuji Hunt Electronics Technology Co., Ltd.) was used as the blue coloring material.
[0073]
An ITO film as the counter electrode 26 was formed to a thickness of 1500 angstrom by sputtering, and polyimide was applied so as to cover the entire surface of the counter electrode 26 and then rubbed to form an alignment film 27.
[0074]
The array substrate 11 was produced as follows. The array substrate 11 was formed by repeating film formation and patterning in the same manner as a process for forming a normal TFT 7 using a known technique. Thereafter, an ITO film is formed to a thickness of 1000 angstroms by sputtering, patterning is performed using a photolithography process, pixel electrodes 15 are formed, and polyimide is applied to cover the pixel electrodes 15 and then rubbed. Thus, the alignment film 16 was formed.
[0075]
Subsequently, the counter substrate 21 and the array substrate 11 were bonded to each other, and then a polarizing plate was attached to each surface on the side opposite to the surface in contact with the liquid crystal (not shown). A light source (not shown) as a backlight of the liquid crystal display device was disposed outside the polarizing plate side of the TFT substrate 11.
[0076]
The liquid crystal composition 28 is a liquid crystal that is sandwiched in the gap (cell gap) between the counter substrate 21 and the TFT substrate 11 and has a general TN (twisted nematic) type composition.
[0077]
In the liquid crystal display element of the present invention, since the alignment failure region 41 due to the spacer 30 is on the light shielding layer 22 for shielding the TFT 12, the alignment irregularity 41 of the liquid crystal caused by the spacer 30 can be made invisible and light leakage occurs. A uniform display without a decrease in contrast due to the above is realized.
[0078]
In the present embodiment, the light shielding layer 22, the color filters 23, 24, 25, and the spacer 30 are disposed on the counter substrate 21. However, the light shielding layer may be disposed on the array substrate 11. 22, when the color filters 23, 24, 25 and the spacer 30 are disposed, the alignment of the counter substrate 21 and the array substrate 11 is not necessary, and a high-quality liquid crystal display device can be manufactured at low cost.
[0079]
A third invention will be described with reference to FIGS.
[0080]
FIG. 11 is a cross-sectional view of a liquid crystal display element for explaining the third invention. In FIG. 11, parts corresponding to those in FIG. The liquid crystal display element includes a color filter substrate 3 having a display electrode 15a, a light shielding layer 22, a red colored layer 23, a green colored layer 24, a blue colored layer 25, an alignment film 22, a spacer 30, and the like on a glass substrate 21; A counter substrate 2a having a display electrode 26a, an alignment film 16 and the like on the glass substrate 11 and disposed so as to face the color filter substrate 3, and a liquid crystal composition 28 sandwiched between the two substrates. The main part is composed of
[0081]
In this embodiment, the spacer 30 is formed in a substantially cylindrical shape by laminating a colored layer (red) 23, a colored layer (green) 24, and a colored layer (blue) 25. For this reason, unlike the example shown in FIG. 1, the process of forming the spacer 30 separately is not required. In this embodiment, the arrangement location of the spacer 30 is particularly devised, and the arrangement location of the spacer 30 is to prevent the misalignment region 41 due to the spacer 30 from entering the green colored layer 24. In addition, the green colored layer 24 is not adjacent to the downstream of the spacer 30 in the rubbing direction. Since the color sensitivity characteristic of human vision is high for green and relatively low for blue and red, a colored layer other than the green colored layer 24, that is, the red region 23 or the blue region 25, or the red region. In addition, an alignment defect is caused in the blue region so that display defects due to the alignment defect are made as inconspicuous as possible.
[0082]
FIG. 12 is a plan view schematically illustrating the relationship between the location of the spacers 30 and the poor alignment region 41 of the liquid crystal display element shown in FIG. As can be seen from the figure, since the hair of the rubbing cloth is disturbed by the spacer 30 of the color filter substrate 3, uneven alignment 41 starting from the spacer 30 occurs on the downstream side in the rubbing direction. Here, the rubbing direction is set to a direction of 45 degrees with respect to the vertical or horizontal direction of the liquid crystal display element in order to make the visual field-angle display characteristics in the left-right direction symmetrical.
[0083]
Therefore, the arrangement position of the spacer 30 is set to a position not adjacent to the upstream side of the green colored layer 24 in the rubbing direction. As a result, the influence of the alignment unevenness is removed from the display image as much as possible.
This is effective when the light shielding region 22 is relatively narrow in structure and it is difficult to fit a poorly aligned region within the light shielding region.
[0084]
A method of manufacturing the liquid crystal display element according to this embodiment will be described.
First, the color filter substrate 3 is manufactured as follows.
[0085]
The light shielding layer 22, the color filters 23-25, and the spacer 30 were formed on the glass substrate 21 using the well-known photolithography process.
[0086]
More specifically, a photosensitive black resin is applied onto the glass substrate 21 using a spinner, dried at 90 ° C. for 10 minutes, and then irradiated with ultraviolet rays through a photomask having a predetermined pattern shape at 300 mJ / cm 2. After irradiation with an exposure amount, development was performed with an alkaline aqueous solution having a pH of 11.5, followed by baking at 200 ° C. for 60 minutes to form a light shielding layer 22 having a thickness of 1.5 (μm). Subsequently, a photosensitive resist CR-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) in which a red pigment is dispersed is applied over the entire surface using a spinner, dried at 90 ° C. for 10 minutes, and then the spacer 30 as a starting point. Including the formation of the spacer 30 so that the alignment unevenness 41 is only the blue pixel region, the exposure amount is set to 100 mJ / cm @ 2 through a photomask in which only the portion where the red colored layer 23 is formed is irradiated with ultraviolet rays. The exposure was performed. Development was carried out with a 1 wt% potassium hydroxide aqueous solution for 20 seconds, followed by baking at 200 ° C. for 60 minutes to form a red colored layer.
[0087]
Similarly, a color filter in which the thickness of each colored layer is 1.5 (μm) is formed by repeatedly forming green and blue colored layers, but the spacer 30 is not formed in the green and blue colored layers. In other words, a spacer 30 consisting only of a red colored layer was obtained on the light shielding layer 22.
[0088]
Here, CG-2000 (Fuji Hunt Electronics Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (Fuji Hunt Electronics Technology Co., Ltd.) was used as the blue coloring material.
[0089]
Thereafter, an ITO film is formed as a display electrode 15a to a thickness of 1500 angstrom by sputtering, and is striped using a known photolithography process so that the line width is 80 (μm) and the interval is 20 (μm). Patterned. Next, an alignment film 27 was formed by applying a rubbing process after applying polyimide so as to cover the entire surface of the display electrode 15a.
[0090]
The counter substrate 2a was produced as follows.
An ITO film is formed as a display electrode 26a on the glass substrate 11 to a thickness of 1500 angstrom by sputtering, and a line width of 80 (μm) and an interval of 20 (μm) are obtained using a known photolithography method. Were patterned in stripes. Next, the alignment film 16 was formed by applying a rubbing process after applying polyimide so as to cover the entire surface of the display electrode 26a.
[0091]
After the color filter substrate 3 and the counter substrate 2a were bonded together, polarizing plates were respectively attached to the surfaces of the two substrates opposite to the surfaces in contact with the liquid crystal (not shown). A light source (not shown) as a backlight of the liquid crystal display element was disposed outside the polarizing plate side of the color filter substrate 3.
[0092]
The liquid crystal composition 28 is a liquid crystal sandwiched in a gap (cell gap) between the color filter substrate 3 and the counter substrate 2a, and uses a ferroelectric liquid crystal.
[0093]
In the liquid crystal display element of the present invention, since the alignment defect region due to the spacer 30 is only the blue pixel region, the liquid crystal alignment unevenness 41 caused by the spacer is high-quality display that is not noticeable visually.
[0094]
Next, an embodiment of the present invention that maintains the mechanical strength of the spacer will be described.
[0095]
The table shown in FIG. 19 confirms the defect state of the spacer by performing a rubbing process that requires the most mechanical strength of the spacer in order to confirm the mechanical strength of the elliptical spacer.
[0096]
The height of the spacer of the TFT-liquid crystal display element was 5 μm, the width D of the light shielding layer was 25 μm, the major axis a and the minor axis b were set to various values, and the defect state was observed. ○ in the table indicates that the spacer has no obvious defect after rubbing, Δ indicates that the spacer has an obvious defect after rubbing, × indicates that the spacer has an obvious defect after rubbing Show. In addition, (circle) outside the double frame line in a table | surface is a part where the magnitude | size of a major axis and a minor axis becomes reverse.
[0097]
As a result, when the short axis b of the spacer was smaller than (2 × H), the absence of the spacer was recognized in the rubbing process. The major axis a and the minor axis b are a> b. Since the direction of the major axis a of the spacer is the same (parallel) angle of 45 degrees as the rubbing direction, a spacer having a length twice as long as the root of the light shielding layer width D can be disposed. The limit that does not protrude is a <((2) ^1/2 XD).
[0098]
Therefore, the shape condition of the elliptical spacer is
In the case of active matrix liquid crystal elements,
(2 × H) ≦ b <a ≦ ((2) ^1/2 × D)
In the case of a simple matrix type liquid crystal display element,
(2 × H) ≦ b <a ≦ ((2) ^1/2 × W)
Here, W is an interval between the display electrodes.
[0099]
According to the fourth aspect of the active matrix type liquid crystal display element and the fifth aspect of the simple matrix type liquid crystal display element, in the rubbing step of imparting alignment to the alignment film that requires the most mechanical strength of the spacer. However, since the spacer has an elliptic cylinder and the major axis direction of the spacer is parallel to the alignment direction of the alignment film, the strength of the spacer can be maintained and the load applied to the spacer can be minimized. If the minor axis is not more than twice the height of the spacer, the mechanical strength of the spacer will be insufficient. In the active matrix liquid crystal display element, the width of the light-shielding layer is smaller than in the simple matrix liquid crystal display element. If it is larger, the spacer enters the pixel, so that the display quality is lowered.
[0100]
In addition, in order to accurately control the distance between the two substrates, the distribution density of the spacers on the substrate is also an important factor. In order to achieve the inter-substrate distance of about 1 to 10 (μm) required for a normal liquid crystal display device, the total cross-sectional area in a plane parallel to the substrate occupying per square millimeter of the spacer is 0.0001. It must be greater than square millimeters and less than 0.002 square millimeters. Below 0.0001 square millimeters per square millimeter, the mechanical strength as a spacer is insufficient, and it becomes difficult to uniformly and precisely control the distance between two substrates within the screen. Also, at 0.002 square millimeters or more per square millimeter, the so-called “low temperature foaming” that occurs when the liquid crystal display device is cooled (the vacuum region is larger because the thermal expansion coefficient of the liquid crystal is larger than the thermal expansion coefficient of the liquid crystal display device). Are generated, and bubbles are likely to occur), and it is difficult to inject liquid crystal and display quality is deteriorated.
[0101]
Furthermore, the spacers can be arranged without increasing the number of processes by forming the spacers at the same time as the color filter, which is a constituent material of the color liquid crystal display device, and is necessary for the conventional liquid crystal display device. The dispersion | distribution dispersion | distribution process of a spacer (bead) can be made.
[0102]
In addition, since the major axis direction of the spacer faces the direction in which the liquid crystal can be uniformly injected into the entire surface of the liquid crystal display device, the liquid crystal can be easily injected.
[0103]
FIG. 13 is a cross-sectional view of the active matrix liquid crystal display element according to the fourth aspect of the present invention, and has the same configuration as that of FIG. D shown in FIG. 13 represents the width of the light shielding layer 22.
[0104]
FIG. 15 shows the shape of the spacer 30, and the spacer 30 has an elliptical shape with a major axis “a”, a minor axis “b”, and a height “H”. The spacer 30 has (2 × H) ≦ b <a ≦ ((2) ^1/2 XD). Here, the major axis a of the spacer is (2) rather than the width D of the light shielding layer. ^1/2 The reason why the size is allowed to be double is that the major axis direction 43 of the spacer is disposed in the light shielding layer obliquely in the same 45 degree direction as the orientation direction 42.
[0105]
FIG. 16 further considers reducing damage to the rubbing cloth, and the portion where the elliptical rubbing cloth first hits has an apex angle and has a tapered surface.
[0106]
FIG. 14 is a plan view showing the major axis direction 43 and the orientation direction (rubbing direction) 42 of the spacer 30 of the counter substrate 2 of FIG. The major axis direction 43 of the spacer 30 is set to be the same as the orientation direction (rubbing direction) 42.
[0107]
A method of manufacturing the liquid crystal display element according to this embodiment will be described.
First, the counter substrate 2 was produced as follows.
The light shielding layer 22, the red, green, and blue color filters 23 to 35 and the spacer 30 were formed using a known photolithography process.
[0108]
Specifically, a photosensitive black resin is applied on the glass substrate 21 using a spinner, dried at 90 ° C. for 10 minutes, and then a photomask having a pattern shape in which the light shielding layer 22 has a width of 30 (μm). Then, the light-shielding layer 5 having a thickness of 2.0 (μm) is formed by irradiating with UV light at an exposure amount of 300 mJ / cm 2, developing with an alkaline aqueous solution with pH = 11.5, and baking at 200 ° C. for 60 minutes. Formed.
[0109]
Subsequently, a photosensitive resist CR-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) in which a red pigment is dispersed is applied over the entire surface using a spinner. After drying at 90 ° C. for 10 minutes, the size of the spacer 3 is increased. The minor axis 15 (μm), the major axis 25 (μm), the orientation of the major axis of the spacer 3 is parallel to the orientation direction of the alignment film 6, and the total cross-sectional area occupied by the spacer 3 per square millimeter is 0. Including the formation of the spacer 3 having a thickness of 0009 square millimeters, exposure was performed so that the exposure amount would be 100 mJ / cm @ 2 through a photomask in which only the portion forming the red colored layer was irradiated with ultraviolet rays. . Next, development was carried out with a 1 wt% potassium hydroxide aqueous solution for 20 seconds, followed by baking at 200 ° C. for 60 minutes to form a red colored layer.
[0110]
Similarly, three colors are formed on the light-shielding layer 22 and the color filters 23 to 25 each having a thickness of 1.5 (μm) by repeatedly forming green and blue colored layers including the formation of spacers. As a result, a spacer 30 on which the colored layer was superimposed was obtained.
[0111]
Here, CG-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was used as the blue coloring material.
[0112]
Thereafter, an ITO film as the counter electrode 26 was formed to a thickness of 1500 angstrom by sputtering, and polyimide was applied so as to cover the entire surface of the counter electrode 26, followed by a rubbing process to form an alignment film 27.
[0113]
The active matrix substrate 1 was produced as follows.
The active matrix substrate 1 was formed by repeating film formation and patterning in the same manner as a process for forming a normal TFT 12 using a known technique. An ITO film is formed to a thickness of 1000 angstrom using a sputtering method, and patterning is performed using a known photolithography process to form the pixel electrode 15. Orientation 16 was formed by applying a rubbing treatment after applying polyimide covering pixel electrode 15.
[0114]
After the active matrix substrate 1 and the counter substrate 2 were bonded to each other, polarizing plates were respectively attached to the surfaces of the two substrates opposite to the surfaces in contact with the liquid crystal (not shown). A light source (not shown) as a backlight of the liquid crystal display device was disposed outside the polarizing plate side of the active matrix substrate 1.
[0115]
The liquid crystal composition 28 is a liquid crystal sandwiched in a gap (cell gap) between the active matrix substrate 1 and the counter substrate 2, and the composition thereof is a general TN (twisted nematic) type.
[0116]
The cell gap of the liquid crystal display device of the present invention was controlled with high accuracy, with an average value of 4.70 (μm), a maximum value of 4.80 (μm), and a minimum value of 4.60 (μm).
[0117]
Further, no defect in the spacer was observed, the contrast ratio was high, and a high-quality display was obtained.
[0118]
In this embodiment, the light shielding layer 22, the color filters 23 to 25, and the spacers 30 are disposed on the counter substrate 2. However, the light shielding layer 22 may be disposed on the active matrix substrate 1. 22, when the color filters 23 to 25 and the spacer 30 are disposed, the alignment of the active matrix substrate 1 and the counter substrate 2 is not necessary, and a high-quality liquid crystal display device can be manufactured at low cost.
[0119]
An embodiment of the fifth invention will be described.
[0120]
FIG. 17 is a cross-sectional view of a simple matrix type liquid crystal display element. The same reference numerals are given to the portions corresponding to those in FIG. 11, and the description of such portions is omitted. In FIG. 17, the liquid crystal display element includes a display electrode 15a, a light shielding layer 22, color filters 23 to 25, an alignment film 27, an elliptical columnar spacer 30, a color filter substrate 3, a display electrode 26a, an alignment film 16, and the like. And a liquid crystal composition 28 sandwiched between the two substrates and the liquid crystal composition 28 disposed so as to face the color filter substrate 3. Here, W shown in the figure represents the interval between the display electrodes on the same substrate, and corresponds to the width D of the light shielding layer in FIG.
[0121]
The spacer 30 has (2 × H) ≦ b <a ≦ ((2) ^1/2 XW) is formed in an elliptical column shape. As described above, H is the height of the spacer, a is the major axis of the spacer (ellipse), and b is the minor axis of the spacer. Here, the major axis a of the spacer is less than the interval W between the display electrodes (2). ^1/2 The reason why it is allowed to be twice as large is that the major axis direction 43 of the spacer is disposed between the display electrodes obliquely in the same 45 degree direction as the orientation direction 42. However, as described later, the major axis direction 43 of the spacer may be directed in a direction different from the orientation direction 42.
[0122]
FIG. 18 is a plan view showing the major axis direction 43 of the spacer 30 and the position 44 of the liquid crystal inlet of the color filter substrate 3 of the liquid crystal display element. This example emphasizes that the liquid crystal composition is more smoothly injected between the two substrates when the gap between the substrates is particularly narrow.
[0123]
For this reason, rather than aligning all the spacers 30 in the alignment direction 42, the major axis direction 43 of each spacer 30 is determined along the inflow direction of the liquid crystal composition 28 injected from the liquid crystal injection port 44. ing. More simply, the direction 43 of the spacer 30 is directed to the liquid crystal injection port 44.
[0124]
As an application example, the major axis direction 43 of a part of the plurality of spacers 30 that hinders the smooth inflow of the injected liquid crystal composition 28 is the inflow direction of the liquid crystal composition 28 injected from the liquid crystal injection port 44 (or The major axis direction 43 of the plurality of spacers 30 that is defined along the direction in which the liquid crystal injection port 44 is located and does not prevent the smooth inflow of the other liquid crystal composition 28 is appropriately aligned with the alignment direction or the like.
[0125]
In this case, the angle θ of the major axis of the spacer 30 is in a state of 0 ° to 45 ° with respect to the vertical direction or the horizontal direction of the matrix.
In case of active liquid crystal display
(2 × H) ≦ b <a ≦ ((1 / cos θ) × D)
For simple matrix type
(2 × H) ≦ b <a ≦ ((1 / cos θ) × W).
[0126]
For example,
When θ = 0 degrees,
(2 × H) ≦ b <a ≦ W
When θ = 45 degrees,
(2 × H) ≦ b <a ≦ ((2) ^1/2 × W)
A method of manufacturing the liquid crystal display element according to this embodiment will be described.
First, the color filter substrate 3 was produced as follows.
[0127]
The light shielding layer 22, the color filters 23 to 25, and the spacer 30 were formed using a known photolithography process. More specifically, a photosensitive black resin is applied onto the glass substrate 21 using a spinner, dried at 90 ° C. for 10 minutes, and then irradiated with ultraviolet rays through a photomask having a predetermined pattern shape at 300 mJ / cm 2. After irradiation with an exposure amount, development was performed with an alkaline aqueous solution having a pH of 11.5, followed by baking at 200 ° C. for 60 minutes to form a light shielding layer 22 having a thickness of 1.5 (μm).
[0128]
Subsequently, a photosensitive resist CR-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) in which a red pigment is dispersed is applied over the entire surface using a spinner, dried at 90 ° C. for 10 minutes, and then the size of the spacer 30 is increased. The minor axis 9 (μm), the major axis 18 (μm), the direction of the major axis of the spacer 30 faces the liquid crystal injection port 44, and the total cross-sectional area occupied by the spacer 30 per square millimeter is 0.0007 square. Including the formation of the spacer 30 in millimeters, the exposure was performed through a photomask in which only the portion where the red colored layer is to be formed is irradiated with ultraviolet rays so that the exposure amount is 100 mJ / cm @ 2. Thereafter, development was carried out with a 1 wt% potassium hydroxide aqueous solution for 20 seconds, followed by baking at 200 ° C. for 60 minutes to form a red colored layer.
[0129]
Similarly, the color filters 23 to 25 having a thickness of 1.5 (μm) are formed by repeatedly forming green and blue colored layers, but the gap between the substrates is relatively narrow. Therefore, the spacer 30 is not formed in the green and blue colored layers, and the spacer 30 including only the red colored layer is formed on the light shielding layer 22. Here, CG-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was used as the blue coloring material.
[0130]
An ITO film was formed as a display electrode 15a to a thickness of 1500 angstrom by sputtering, and patterned in a stripe shape so as to have a line width of 80 (μm) and an interval of 20 (μm) using a known photolithography process. . Next, an alignment film 27 was formed by applying a rubbing process after applying polyimide so as to cover the entire surface of the display electrode 15a.
[0131]
The counter substrate 2a was produced as follows.
[0132]
An ITO film is formed as a display electrode 26a on the glass substrate 11 to a thickness of 1500 angstrom by sputtering, and a line width of 80 (μm) and an interval of 20 (μm) are obtained using a known photolithography method. Were patterned in stripes. Next, the alignment film 16 was formed by applying a rubbing process after applying polyimide so as to cover the entire surface of the display electrode 26a.
[0133]
After the color filter substrate 3 and the counter substrate 2a were bonded together, polarizing plates were respectively attached to the surfaces of the two substrates opposite to the surfaces in contact with the liquid crystal (not shown).
[0134]
A light source (not shown) as a backlight of the liquid crystal display element was disposed outside the polarizing plate side of the color filter substrate 3.
[0135]
The liquid crystal composition 28 is a liquid crystal sandwiched in a gap (cell gap) between the color filter substrate 3 and the counter substrate 2a, and a ferroelectric liquid crystal is used.
[0136]
The cell gap of the liquid crystal display element according to the present embodiment is 1.7 (μm) on average, and is controlled with a maximum value of 1.72 (μm) and a minimum value of 1.68 (μm) with high accuracy. In addition, the direction of the major axis of the spacer 30 is not parallel to the alignment direction of the alignment film 27, but the height of the spacer is low, so that the load applied to the spacer 3 during the rubbing process is small, so that no loss of the spacer is recognized. The contrast ratio was high and a high-quality display was obtained.
[0137]
In this embodiment, since the ferroelectric liquid crystal is used, the liquid crystal material can be injected uniformly in a short time even though the cell gap is as narrow as 1.7 μm on average. I was able to.
[0138]
Further, in this embodiment, the major axis direction 43 of the spacer 30 is all directed to one liquid crystal injection port 44. However, it is only necessary to uniformly inject the entire surface of the liquid crystal display device. An appropriate arrangement can be made such that the flow resistance is minimized.
[0139]
A sixth invention will be described with reference to the drawings.
In order to confirm the mechanical strength of the spacer specified by the height, the maximum width, and the minimum width, the table shown in FIG. It has been confirmed. In this example, since the use of a long spacer is considered, it is not assumed that the direction of the maximum width of the spacer coincides with the rubbing direction. Here, the maximum width of the spacer means the maximum width of the spacer cross section in a plane parallel to the substrate surface. The minimum width of the spacer means the minimum width of the spacer cross section in a plane parallel to the substrate surface.
[0140]
The height of the spacer H of the TFT-liquid crystal display element was 5 μm, the width D of the light shielding layer was 30 μm, the maximum width a and the minimum width b were set to various values, and the defect state of the spacer was observed. ○ in the table indicates that the spacer has no obvious defect after rubbing, Δ indicates that the spacer has an obvious defect after rubbing, × indicates that the spacer has an obvious defect after rubbing Show.
[0141]
As a result, when the minimum width b of the spacer was smaller than the height H of the spacer and the maximum width of the spacer was smaller than the width of the light shielding layer, the absence of the spacer was recognized in the rubbing process. Therefore, the shape conditions of the long spacer are first H ≦ b and D <a.
Furthermore, from the relationship between the maximum width and the minimum width, b <a, and in order to prevent the spacer from protruding into the pixel region, it is necessary that b ≦ D. Therefore, the shape condition of the long spacer is
In the case of active matrix liquid crystal elements,
H ≦ b <D ≦ a
In the case of a simple matrix type liquid crystal display element,
H ≦ b <W ≦ a.
Here, W is an interval between the display electrodes shown in FIG.
[0142]
According to this invention, since the minimum width of the spacer is not less than the height of the spacer and the maximum width of the spacer is larger than the width of the light shielding layer, sufficient mechanical strength as a spacer function can be obtained, and the spacer has the most mechanical strength. In the rubbing process as an alignment process for an alignment film that requires strength, sufficient strength can be obtained without causing spacer chipping or peeling.
[0143]
On the other hand, when the minimum width of the spacer is less than the height of the spacer and the maximum width of the spacer is smaller than the width of the light shielding layer, the mechanical strength as the spacer function is insufficient, and the alignment film is rubbed. Spacer chipping, peeling, etc. occur.
[0144]
Further, since the minimum width of the spacer is smaller than the width of the light shielding layer, the spacer does not enter the pixel, and the display quality does not deteriorate.
[0145]
By forming the spacer in the same material as the color filter that is a constituent material of the color liquid crystal display element and at the same time, the spacer can be arranged without increasing the number of steps. It is possible to eliminate the step of dispersing and dispersing spacers (particles) necessary for conventional liquid crystal display elements.
[0146]
An embodiment of the sixth invention will be described with reference to the drawings.
[0147]
FIG. 21 is a cross-sectional view of the liquid crystal display element according to the present invention. The counter substrate 21 having the counter electrode 26, the spacer 30, the color filters 23 to 25, the light shielding layer 22, the alignment film 26, and the like, and the TFT as the switching element (Thin Film Transistor) 12, scanning line 1 f, pixel electrode 15 as a transparent electrode, alignment film 16, etc., and an active matrix substrate 1 disposed so as to face the counter substrate 2, and a gap between these two substrates The main part is composed of the liquid crystal composition 28 sandwiched between the two.
[0148]
FIG. 22 is a plan view showing the position of the spacer 30 of the counter substrate 2 of the present invention. The spacer 30 has a longitudinal shape, and is rectangular in the illustrated example. The maximum width a, the minimum width b, the height H of the spacer, and the light shielding layer width D are formed so that H ≦ b <D ≦ a.
[0149]
The liquid crystal display element shown in this embodiment can be obtained by the following manufacturing method.
First, the counter substrate 21 was produced as follows.
The light shielding layer 22, the color filters 23 to 25, and the spacer 30 were formed using a known photolithography process.
[0150]
More specifically, a photosensitive black resin is applied onto a glass substrate 21 using a spinner, dried at 90 ° C. for 10 minutes, and then a photomask that has a pattern shape with a width of 25 (μm) for the light shielding layer 5. UV light is irradiated at an exposure dose of 300 mJ / cm @ 2, and then developed with an alkaline aqueous solution with pH = 11.5, and baked at 200 DEG C. for 60 minutes to form a light-shielding layer 5 having a thickness of 2.0 (.mu.m). Formed.
[0151]
Subsequently, a photosensitive resist CR-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) in which a red pigment is dispersed is applied over the entire surface using a spinner, and dried at 90 ° C. for 10 minutes. The minimum width is 15 (μm) and the maximum width is 40 (μm). Only the portion where the red colored layer is formed is irradiated with ultraviolet rays, including the formation of the spacer 30 where the spacer 30 is located on the light shielding layer 22. The exposure was performed through a photomask so that the exposure amount was 100 mJ / cm @ 2.
[0152]
Next, development was carried out with a 1 wt% potassium hydroxide aqueous solution for 20 seconds, followed by baking at 200 ° C. for 60 minutes to form a red colored layer.
Similarly, the green and blue colored layers including the formation of the spacers 3 are repeatedly formed, so that the color filters 23 to 25 each having a thickness of 1.5 (μm) and 3 on the light shielding layer 22. A spacer 30 in which colored layers of color were superimposed was obtained. The height of the spacer 30 from the substrate surface was 6.3 (μm).
[0153]
Here, CG-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was used as the green coloring material, and CB-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) was used as the blue coloring material.
[0154]
Thereafter, an ITO film as a counter electrode 26 was formed to a thickness of 1500 A by a sputtering method, polyimide was applied so as to cover the entire surface of the counter electrode 26, and then an alignment film 26 was formed by rubbing.
[0155]
The active matrix substrate 1 was produced as follows.
An array substrate was formed on the glass substrate 11 by repeating film formation and patterning in the same manner as a process for forming a normal TFT 12 using a known technique. Next, a silicon oxide film is formed to a thickness of 2000A (angstrom) by sputtering, patterning is performed using a known photolithography process, the protective film 1e is formed, and the ITO film is sputtered. The alignment film 16 is formed to a thickness of 1000 A by using a known photolithography process, patterning is performed, the pixel electrode 15 is formed, polyimide is applied so as to cover the pixel electrode 15, and then rubbing is performed. Formed.
[0156]
Next, the active matrix substrate 1 and the counter substrate 2 were bonded together, and then a polarizing plate was affixed on the opposite side of the surfaces of the two substrates that contact the liquid crystal (not shown). A light source (not shown) as a backlight of the liquid crystal display element was disposed outside the polarizing plate side of the active matrix substrate 1.
[0157]
The liquid crystal composition 28 is a liquid crystal sandwiched in a gap (cell gap) between the active matrix substrate 1 and the counter substrate 2, and the composition thereof is a general TN (twisted nematic) type.
[0158]
The cell gap of the liquid crystal display device of the present invention was controlled with high accuracy, with an average value of 4.70 (μm), a maximum value of 4.80 (μm), and a minimum value of 4.60 (μm). Further, no defect in the spacer was observed, the contrast ratio was high, and a high-quality display was obtained.
[0159]
In the above-described embodiment,
(1) Although the cross-sectional shape of the spacer 30 is rectangular, as shown in FIG. 23, it may have any longitudinal shape such as an ellipse, a rhombus, a triangle, and a trapezoid.
[0160]
(2) The light shielding layer 22, the color filters 23 to 25, and the spacer 30 are disposed on the counter substrate 2, but these may be disposed on the active matrix substrate 1. In such a case, alignment between the active matrix substrate 1 and the counter substrate 2 becomes unnecessary, and a high-quality liquid crystal display device can be manufactured at low cost.
[0161]
(3) Although a photosensitive resist in which a pigment is dispersed is used as a color filter material, a colored resin in which a pigment is dispersed is patterned by etching using a known photolithography process regardless of the photosensitive resist. May be.
[0162]
(4) Although a photosensitive resist in which a pigment is dispersed is used as a material for the light shielding layer 22, a colored resin in which a pigment is dispersed is patterned by etching using a known photolithography process regardless of the photosensitive resist. You may do it. Further, it may be other than a resin such as metal chromium (Cr) or chromium oxide (CrO).
[0163]
The non-light-shielding member may also serve as the light-shielding layer without providing the light-shielding layer 22, and even if the spacer 30 is provided on the non-light-transmissive member, the same effect as the present invention can be obtained.
[0164]
(5) Although the active matrix type liquid crystal display element is described, a simple matrix type liquid crystal display element or the like may be used.
[0165]
(6) The spacers 3 are formed by overlapping three colored layers, but it is sufficient that a desired cell gap is obtained with two or one color.
[0166]
【The invention's effect】
According to the first aspect of the present invention, the bristle feet smoothly move around the spacer so that the apex portion of the spacer first hits the rubbing feet of the rubbing cloth, and the rubbing cloth has its fur feet by tapering. Since the resistance received is reduced, it is possible to prevent display defects due to bending of the hair of the rubbing cloth, and a liquid crystal display element with high display performance and high reliability can be obtained. Moreover, it becomes possible to reduce the damage to the rubbing cloth as a whole by aligning the entire arrangement of the spacers in the rubbing direction.
[0167]
According to the second invention, since the spacer is disposed at a position where the alignment failure region generated by the alignment process such as rubbing with the spacer as the starting point does not reach the inside of the pixel, it is possible to prevent the display quality from being deteriorated. .
[0168]
According to the third aspect of the present invention, the spacers are arranged so that the alignment defect area generated by the alignment process such as rubbing starting from the spacer does not enter the relatively sensitive green pixel area in human visual characteristics. Therefore, it is possible to suppress the deterioration of display quality as much as possible.
[0169]
According to the second and third inventions, the spacer is not formed in a special shape as in the first invention, so the filter is made of the same material as the color filter that is a constituent material of the color liquid crystal display device. At the same time, the spacers can be formed without increasing the number of steps.
[0170]
According to the fourth and fifth inventions, even in a rubbing process for imparting orientation to an alignment film that requires the most mechanical strength of the spacer, the shape of the spacer is an elliptical column, the height H of the spacer, the spacer In the active matrix type liquid crystal display device, (2 × H) ≦ b <a ≦ (( 2) ^1/2 XD) and the simple matrix type liquid crystal display device satisfies (2 × H) ≦ b <a ≦ ((2) ^1/2 By satisfying the condition of (W) and making the major axis direction of the spacer the same as the alignment direction of the alignment film, the strength of the spacer can be maintained and the load applied to the spacer can be minimized.
[0171]
Further, in order to uniformly realize the inter-substrate distance of about 1 to 10 (μm) required for a normal liquid crystal display device, the total of the cross-sectional areas in the plane parallel to the substrate is occupied by the spacer per square millimeter. , Exceeding 0.0001 square millimeters and less than 0.002 square millimeters, the distance between the two substrates can be controlled uniformly and precisely within the screen.
[0172]
By defining the major axis direction of the spacer along the inflow direction of the liquid crystal in the gap between the two substrates and reducing the resistance, the liquid crystal can be easily injected while maintaining the mechanical strength as the spacer.
[0173]
In the liquid crystal display element of the sixth invention, since the spacer shape is determined so that the height H of the spacer ≦ the minimum width b of the spacer ≦ the light shielding layer width D <the maximum width a of the spacer, Sufficient strength is obtained so that the spacer is not chipped or peeled off even in a rubbing process as an alignment process for an alignment film that requires the most mechanical strength of the spacer.
[0174]
Further, since the minimum width of the spacer is smaller than the width of the light shielding layer, the spacer does not enter the pixel, so that the display quality is not deteriorated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
2 is a cross-sectional view illustrating a configuration of an active matrix substrate 1. FIG.
FIG. 3 is an explanatory diagram for explaining an outline of a spacer shape in the liquid crystal display element of the present invention.
FIG. 4 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
FIG. 5 is an explanatory view for explaining an outline of a spacer shape in the liquid crystal display element of the present invention.
FIG. 6 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
FIG. 7 is an explanatory diagram for explaining an outline of a spacer shape in the liquid crystal display element of the present invention.
FIG. 8 is an explanatory diagram illustrating an example of the arrangement of spacers in the liquid crystal display element of the present invention.
FIG. 9 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
FIG. 10 is an explanatory diagram illustrating a location of spacers in the liquid crystal display element of the present invention.
FIG. 11 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
FIG. 12 is an explanatory diagram for explaining the location of spacers in the liquid crystal display element of the present invention.
FIG. 13 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
FIG. 14 is an explanatory diagram for explaining an arrangement place and direction of an elliptic columnar spacer in the liquid crystal display element of the present invention.
FIG. 15 is a perspective view illustrating an example of an elliptic columnar spacer.
FIG. 16 is a perspective view illustrating another example of an elliptic columnar spacer.
FIG. 17 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
FIG. 18 is an explanatory diagram for explaining the location and direction of spacers in the liquid crystal display element of the present invention.
FIG. 19 is a diagram showing an experimental result of damage received by the rubbing process on the elliptical column spacer in which the major axis direction is arranged in the same direction as the rubbing direction.
FIG. 20 is a diagram illustrating an experimental result of damage that a longitudinal spacer having a longitudinal direction arranged in a direction unrelated to the rubbing direction receives by rubbing treatment;
FIG. 21 is a cross-sectional view illustrating an outline of a liquid crystal display element of the present invention.
FIG. 22 is an explanatory diagram for explaining the location and direction of the longitudinal spacer in the liquid crystal display element of the present invention.
FIG. 23 is an explanatory diagram illustrating an example of a longitudinal spacer.
[Explanation of symbols]
1 Active matrix substrate
2 Counter substrate
3 Color filter substrate
11, 21 Glass substrate
12 Active device (TFT)
15 pixel electrodes,
15a display electrode
14 Gate line
13 Signal line
16, 27 Alignment film
22 Shading layer
23 Colored layer (R)
24 Colored layer (G)
25 Colored layer (B)
26 Common electrode
26a Display electrode
28 Liquid crystal composition
30 Spacer
31 TFT shading area
41 Misalignment region
42 Orientation direction (rubbing direction)
43 Major axis direction of spacer
44 Liquid crystal inlet

Claims (3)

A light-shielding layer that opens a plurality of pixel regions in a matrix shape or stripe shape between two insulating substrates that are arranged to face each other and sandwich a liquid crystal therebetween, and a color filter that is arranged in the opened portion A liquid crystal display element having at least a spacer that secures a gap between the two insulating substrates, and an alignment film that is subjected to an alignment treatment that provides alignment in a specific direction to the liquid crystal,
The spacer is located in the vicinity of the opening on the light shielding layer, and is arranged at a position not adjacent to the green color filter on the downstream side in the specific direction from this position,
The alignment failure region generated by performing the alignment process on the alignment film is not formed in the green color filter region in the region where the color filter is disposed, and the red color filter region and / or the blue color filter region is not formed. A liquid crystal display element formed in a color filter region. The spacer is disposed adjacent to a red filter region, a blue filter region, or both regions of the red filter and the blue filter.
The liquid crystal display element according to claim 1.   4. The liquid crystal display element according to claim 2, wherein the spacer is made of the same material as the color filter and is formed at the same time.

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