KR20070054014A - Liquid crystal display and method of fabricating the same - Google Patents

Abstract

A liquid crystal display device and a method of manufacturing the same are provided. The device includes a first substrate having sustain electrodes and thin film transistors, a second substrate having a light shielding film pattern and spaced apart by a predetermined cell gap from the first substrate, a first substrate disposed between the first substrate and the second substrate; Second color filters, and a first spacer and a second spacer disposed on the first and second color filters, respectively, between the first substrate and the second substrate. In this case, the first color filter is thicker than the second color filter, and the first and second spacers are selectively disposed in a region where a light shielding pattern is formed or in a region where a storage electrode is formed.

Description

Liquid crystal display and manufacturing method therefor {Liquid Crystal Display And Method Of Fabricating The Same}

1A to 1F are diagrams for describing a spacer forming method of a liquid crystal display according to the present invention.

2 is a plan view illustrating a portion of a pixel area of a liquid crystal display according to the present invention.

3A to 3C are cross-sectional views illustrating a liquid crystal display device having a spacer structure according to the present invention.

The present invention relates to a liquid crystal display device and a manufacturing method thereof.

The liquid crystal display is one of the flat panel display devices most widely used at present, and includes upper and lower substrates on which electrodes are formed, and a liquid crystal layer disposed between the substrates. In this case, the liquid crystal molecules of the liquid crystal layer may be rearranged by a voltage applied to the electrodes, and the rearrangement of the liquid crystal molecules changes the transmittance of light passing through the liquid crystal layer. This characteristic is called the electro-optical effect of the liquid crystal, and the liquid crystal display device uses the electro-optic effect of the liquid crystal to express electrical information as visual information.

On the other hand, since the gap between the upper and lower substrates (ie, cell gap) determines the thickness of the liquid crystal layer, the product characteristics of the liquid crystal display device largely depend on the size and uniformity of the cell gap. Accordingly, the liquid crystal display includes spacers disposed between two substrates to maintain the cell gap constant.

The spacers can be broadly classified into beads spacers and column spacers. Initially, a method of randomly arranging the bead spacers on the substrate using a spray method (hereinafter, referred to as a spray process) was mainly used. However, such a spray process does not selectively control the position where the bead spacer is disposed, so that the bead spacer may be disposed in the opening region of the pixel. In this case, technical problems such as an increase in light leakage or a decrease in aperture ratio occur.

In contrast, since the column spacer is patterned through a predetermined photo and etching step, the column spacer may be selectively formed at a predetermined position. Accordingly, as an alternative for overcoming the above-mentioned problems of the bead spacer by the spray process, the column spacer is attracting attention and is being used. However, since the column spacer requires a photo-etching step as described above, it is accompanied with a problem of an increase in manufacturing cost according to an increase in the process step.

In addition, since the column spacer has a poor restoring property (ie, elastic force) compared to the bead spacer, it has a technical disadvantage that it is difficult to simultaneously improve the liquid crystal dropping amount margin property and smear tolerance.

More specifically, since the liquid crystal is injected between the two substrates on which the spacers are disposed, it should be injected in a predetermined amount necessary to fill the space between the two substrates. In this case, the liquid crystal drop margin means a variation in the amount of liquid crystal that is allowed for the stable progress of the filling process. That is, the larger the liquid crystal dropping margin, the more stable the filling process can be performed. The liquid crystal dropping margin is determined by the pressure outside the substrate and the restoring force of the spacer. However, since the column spacer has poor recovery characteristics as described above, it is difficult to improve the liquid crystal drop amount margin.

The smear phenomenon is a phenomenon in which a spot pattern appears on the liquid crystal display due to damage of a spacer or a lower structure thereof caused by an impact outside the substrate. Since the smear phenomenon is intensified when the external shock is concentrated in a predetermined area, it is necessary to arrange the spacers so as to disperse the external shock in order to increase the resistance to the smear phenomenon. For example, a method of disposing a larger number of spacers may be used to disperse external impacts. However, as described above, since the column spacers have poor recovery characteristics, the increase in the number of spacers makes it difficult to improve the liquid crystal dropping margin.

Recently, researches for producing the column spacers with materials having excellent restoring properties have been conducted, but still, the problems of the above-described column spacers are not completely overcome. In addition, a technique for forming the bead spacers in a roll-print manner having excellent restoring properties has been proposed, but this method has limitations in improving smear resistance. In another manner, a technique for arranging beads spacers of different sizes in a roll-print manner has been proposed, but this method has another problem of nozzle clogging due to the difference in the size of the beads spacers.

An object of the present invention is to provide a liquid crystal display device that can reduce the light leakage phenomenon.

Another object of the present invention is to provide a liquid crystal display device capable of increasing liquid crystal dropping margin and smear resistance.

Another object of the present invention is to provide a method of manufacturing a liquid crystal display device capable of selectively controlling the positions of spacers.

Another object of the present invention is to provide a method of manufacturing a liquid crystal display device capable of increasing liquid crystal dropping margin and smear resistance.

In order to achieve the above technical problem, the present invention provides a liquid crystal display device in which spacers are disposed under color filters having different heights. The device includes a first substrate having sustain electrodes and thin film transistors, a second substrate having a light shielding film pattern, and spaced apart from the first substrate by a predetermined cell gap, and disposed between the first substrate and the second substrate. And first and second color filters and first and second spacers disposed on the first and second color filters, respectively, between the first and second substrates. In this case, the first color filter is thicker than the second color filter, and the first and second spacers are selectively disposed in a region where a light shielding pattern is formed or a region where a sustain electrode is formed.

According to embodiments of the present invention, the first spacer and the second spacer may have the same size and be made of the same material within an error range of 10%.

According to an embodiment of the present invention, the method may further include a third color filter disposed between the first substrate and the second substrate. In this case, the first color filter is a blue filter, the second color filter is a red filter, the third color filter is a green filter, the third color filter is thinner than the first color filter and the second color filter Thicker ones are preferred.

According to an embodiment of the present invention, the third substrate may further include a third spacer disposed on the third color filter between the first substrate and the second substrate. Preferably, the third spacer has the same size and is made of the same material within the error range of 10% with the first spacer. In addition, the first, second and third spacers are selectively disposed in at least one region between the light shielding pattern of the first substrate and the second substrate and between the sustain electrode of the first substrate and the second substrate. .

According to one embodiment of the present invention, the first spacer and the second spacer may be a bead-shaped spacer including a plurality of aggregated sub-bead spacers.

According to an embodiment of the present invention, the first spacer and the second spacer may be an acryl organic compound, Teflon, benzocyclobutene (BCB), cytotope, and perfluorocyclobutene. (perfluorocyclobutene, PFCB) may be made of at least one.

According to an embodiment of the present invention, the first and second color filters are formed on the second substrate, and the first spacer is the first color filter between the light shielding pattern of the first substrate and the second substrate. The second spacer is disposed on the second color filter between the light blocking film pattern of the first substrate and the second substrate.

According to an embodiment of the present invention, the first and second color filters are formed on the first substrate, the first spacer is disposed between the light shielding pattern and the first color filter, and the second spacer May be disposed between the light shielding pattern and the second color filter.

In order to achieve the above technical problem, the present invention provides a method of manufacturing a liquid crystal display device in which spacers are disposed under color filters having different heights. The method forms first thin film transistors on a first substrate, forms a light shielding film pattern on a second substrate, and then first, second, and third portions disposed on the second substrate to extend over the light shielding film pattern. Forming color filters. Subsequently, first and second spacers are simultaneously formed on the first and third color filters, respectively, and the first and second substrates are bonded to each other, and then between the first and second substrates. Inject the liquid crystal into it. In this case, the first color filter is formed thicker than the third color filter so that the distance between the first substrate and the second substrate is determined by the first spacer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed subject matter is thorough and complete, and that the spirit of the present invention to those skilled in the art will fully convey. In the drawings, the thicknesses of layers and regions are exaggerated for clarity. If it is also mentioned that the layer is on another layer or substrate it may be formed in direct contact with the top or bottom of the other layer or substrate or a third layer may be interposed therebetween.

1A to 1F are diagrams for describing a spacer forming method of a liquid crystal display according to the present invention. In the method of forming a spacer of the liquid crystal display according to the present invention, after preparing the spacers 100 using the spacer template substrate 13, the spacers 100 may be formed using the roll-print process. And transferring to. 1A and 1B are diagrams for describing a step of preparing the spacers 100 using the spacer mold substrate 13, and FIGS. 1C to 1F are diagrams illustrating the spacers using a roll-print process. FIG. 14 is a diagram for explaining a step of transferring 100 to the liquid crystal display substrate 14. 2A to 2C are cross-sectional views illustrating a liquid crystal display device having a spacer structure according to the present invention.

Referring to FIGS. 1A and 1B, spacers 100 arranged spatially on a spacer mold substrate 13 having a plurality of grooves 99 are formed. In this case, the spacer mold substrate 13 may be manufactured using a mold method or a laser processing method, and may be formed of at least one of glass, plastic, and metal material (SUS). The position of the grooves 99 determines a position where the spacers 100 are arranged on the liquid crystal display substrate 14. Therefore, the positions of the grooves 99 are formed in consideration of the structure of the liquid crystal display. The location where the spacers 100 are formed will be described in more detail later with reference to FIG. 2.

The spacers 100 may be formed using a doctor blade, a transfer roller 24 having a transfer sheet 23, and a predetermined spacer supply device having a spacer supply device. The spacer supply device supplies predetermined spacer forming materials to the spacer mold substrate 13, and the doctor blade uniformly injects the spacer forming material loaded on the spacer mold substrate 13 into the grooves 99. It is used to

According to one embodiment of the present invention, the spacer forming material is a material capable of forming a polymer (for example, an acrylic organic compound, Teflon, benzocyclobutene (BCB)) And sub-bead spacers consisting of cytope and perfluorocyclobutene (PFCB). The sub-bead spacers are preferably made of an organic material having a low dielectric constant, and have a smaller size than the grooves 99. In this case, the sub-bead spacer is preferably about the size of 1/15 of the volume of the groove 99 so that at least 10 beads spacers can be disposed in one groove (99). In addition, the spacer forming material may further include a thermal curing agent or an ultraviolet curing agent.

1C and 1D, the spacers 100 formed on the spacer mold substrate 13 are attached to the transfer sheet 23 of the transfer roller 24. Attaching the spacers 100 to the transfer sheet 23 includes rolling the transfer roller 24 onto the spacer mold substrate 13. At this time, it is preferable that the transfer roller 24 is rolling while applying a predetermined pressure to the spacer mold substrate 13. Accordingly, the spacers 100 formed on the spacer mold substrate 13 are attached to the surface of the transfer sheet 23, and the positions of the spacers 100 attached on the transfer sheet 23 are located in the grooves. Corresponds to the position of 99. In addition, in order to facilitate attachment of the spacers 100, the transfer sheet 23 is formed of a material having excellent adhesion to the spacer 100. For example, the transfer sheet 23 may be made of a silicon material.

1E and 1F, the spacers 100 attached to the transfer sheet 23 are moved to a predetermined position of the liquid crystal display substrate 14. Transferring and attaching the spacers 100 to the liquid crystal display substrate 14 includes rolling the transfer roller 24 onto the liquid crystal display substrate 14. In this case, the transfer roller 24 is preferably rolled while applying a predetermined pressure to the liquid crystal display substrate 14. Accordingly, the spacers 100 attached to the transfer sheet 23 are reattached to the upper surface of the liquid crystal display substrate 14, and the positions of the spacers 100 to be reattached are determined by the grooves 99. Corresponds to the array position.

Meanwhile, before the spacer forming process described above, the light blocking film pattern 250 and the color filters are formed on the liquid crystal display substrate 14. In addition, an alignment layer (not shown) may be further formed on the color filters to determine the direction of the liquid crystal molecules.

The color filters are configured to filter at least three different colors, and each color filter compensates for a difference in optical characteristics (eg, a change in luminance due to a difference in transmittance) according to a wavelength of light (ie, color). It can be formed in different thicknesses. According to one embodiment of the invention, the color filters, as shown, is composed of a red filter (200R), a green filter (200G) and a blue filter (200B), the blue filter (200B) is the green filter ( 200G), and the green filter 200G is thicker than the red filter 200R. In addition, the color filters are formed between the light blocking film patterns 250 and extend to an upper portion of the light blocking film pattern 250. In this case, as described above, since the color filters have different thicknesses according to colors, the heights of the color filters extending on the light shielding pattern 250 also vary depending on the color.

According to the present invention, the spacers 100 are disposed under the light blocking film pattern 250, and are disposed below the color filter having the thickest thickness and the color filter having the thinnest thickness. According to an embodiment of the present invention, the spacers 100 (as shown in FIGS. 3A and 3B) may extend the blue filter 200B and the red filter 200R to the light shielding pattern 250. It is placed at the bottom of the. In this case, the thickness h ₃ of the blue filter 200B is thicker than the thickness h ₁ of the red filter 200R and the thickness h ₂ of the green filter 200G. Accordingly, the spacer 100 formed on the blue filter 200B determines a cell gap of the liquid crystal display according to the present invention. Since the cell gap is a parameter for determining the injection amount of the liquid crystal injected into the liquid crystal display, the spacer 100 formed on the blue filter 200B determines the liquid crystal drop amount margin. In addition, since the spacer 100 according to the present invention is made of a beads spacer having excellent restoring characteristics (that is, elastic force) as described above, the liquid crystal display according to the present invention has a spacer or a lower portion thereof caused by an impact on the outside of the substrate. Excellent resistance to breakage of the structure. Nevertheless, the liquid crystal display substrate 14 When an impact of a predetermined size or more is applied, since the impact is concentrated on the spacer 100 formed on the blue filter 200B, a smear phenomenon may appear as described in the related art.

On the other hand, since the red filter 200R is the thinnest color filter, it does not affect the cell gap. However, when the liquid crystal display substrate 14 is deformed to a predetermined size or more by the external impact (for example, the liquid crystal display substrate 14 has a thickness of the blue filter 200B and the red filter 200R). When the deformation is greater than the difference (h ₃ -h ₁ ), the impact is also applied to the spacer 100 formed on the red filter 200R. In this case, since the external shock is applied to both the spacers 100 formed on the blue filter 200B and the red filter 200R, the impact is dispersed. As a result, the liquid crystal display according to the exemplary embodiment has improved smear resistance compared to the case where the spacer 100 is disposed only under the blue filter 200B.

In this case, as described above, since the spacers 200 are formed through the same spacer forming process, the spacers 200 may be formed of the same material and have the same size. Considering the process variation in the spacer forming process, the spacers 100 are formed to the same size within 10%. That is, according to the present invention, the spacers 100 disposed below the red filter 200R and the blue filter 200B have the same size and are made of the same material within 10%.

In addition, as described above, since the spacers 100 are selectively arranged on the light shielding pattern 250, light leakage and decrease in aperture ratio of the liquid crystal display by the spacers (as described in the related art) may be prevented. have. This selective arrangement of the spacers 100 may be achieved by forming the grooves 99 to correspond to the positions of the light blocking film patterns 250. In addition, in order for the spacers 100 to be accurately arranged on the light shielding film pattern 250, the separation distance between the spacer mold substrate 13 and the liquid crystal display substrate 14, and the transfer roller 24 of the transfer roller 24. Fine adjustment of radius and rotation speed is necessary.

According to another embodiment of the present invention, the spacer 100 may be disposed under the green filter 200G (see FIG. 3C). In this case, the spacer 100 formed on the green filter 200G, together with the spacers 100 formed on the red filter 200R and the blue filter 200B, may form the liquid crystal display substrate 14. It is possible to more effectively disperse the external impact applied to the. As a result, the liquid crystal display according to this embodiment can have further improved smear resistance. However, in this case, since the difference between the thicknesses of the red filter 200R and the blue filter 200B is small, the liquid crystal dropping margin may be reduced. Therefore, this embodiment is preferably adopted when the liquid crystal dropping amount margin is sufficient but the smear resistance is insufficient.

Thereafter, curing the spacers 100 formed on the liquid crystal display substrate 14, bonding the liquid crystal display substrate 14 and the lower substrate 1 on which predetermined thin film transistors are formed, and bonding Injecting liquid crystal between the substrates 1, 14 is further carried out. In this case, the curing of the spacers 100 preferably includes irradiating heat or ultraviolet rays to cure the thermal curing agent or ultraviolet curing agent as described above.

The lower substrate 1 including the thin film transistor is prepared through a separate process from preparing the liquid crystal display substrate 14. FIG. 2 is a plan view showing a portion of a pixel area of a liquid crystal display according to the present invention, and FIGS. 3A to 3C are cross-sectional views showing cross sections taken along the dotted line II ′ of FIG. 2. 2 and 3A to 3C, the lower substrate 1 includes the gate electrode 10a, the gate insulating layer 20, the active pattern 31, and the source / drain electrodes 40a and 40b. Thin film transistors are formed. The thin film transistors are connected to a gate line GL and a data line DL across the gate line GL, as shown in FIG. 2. Preferably, an ohmic contact pattern 32 is interposed between the source / drain electrodes 40a and 40b and the active pattern 31. The ohmic contact pattern 32 and the active pattern 31 constitute a semiconductor pattern 30 of a thin film transistor. A passivation layer 50 having a contact hole 71 exposing a predetermined region of the source / drain electrode 40b is disposed on the thin film transistor, and the source layer is formed on the passivation layer 50 through the contact hole 71. The pixel electrode 60 is connected to the drain electrode 40b.

Meanwhile, according to another embodiment of the present invention, the color filters may be formed on the lower substrate 1 on which the thin film transistors are disposed. According to this embodiment, like the above-described embodiment, the color filters may be composed of a red filter, a green filter, and a blue filter, wherein the blue filter is thicker than the green filter, and the green filter is thicker than the red filter. It is preferably formed. In this case, the spacers may be disposed on the color filter having the thickest thickness (ie, the blue filter) and the color filter having the thinnest thickness (ie, the red filter). In more detail, the spacers are disposed between the light blocking layer pattern 250 and the color filters (ie, the blue and red filters).

According to a modified embodiment of this embodiment, the spacer may be arranged on top of the green filter. These embodiments can also achieve the same technical effects described above (that is, the effect of increasing the liquid crystal dropping amount and smear resistance by the spacer).

On the other hand, the lower substrate 1 according to the present invention may be disposed with the pixel electrode 60 and the sustain electrode 65 constituting a predetermined capacitor structure. By the sustain electrode 65, a sudden damping of the voltage applied to the pixel electrode 60 may be minimized. The sustain electrode 65 may be formed of the same material as the gate electrode 10a and thus optically opaque. According to another modified embodiment of the present invention, the spacers may be disposed above the sustain electrode 65. In this case, since the thickness of the color filters depends on the color as described above, the distance between the spacers and the lower substrate 1 depends on the color of the color filters. As a result, this modified embodiment can also obtain the same technical effect as that of the embodiments described above (that is, the effect of increasing liquid crystal dropping margin and smear resistance). In this case, the spacers may be selectively disposed on the sustain electrode 65 through the roll-print process described above with reference to FIGS. 1A to 1F.

According to the present invention, the beads spacers are arranged under the color filters having different thicknesses. Accordingly, the light leakage phenomenon and the reduction of the aperture ratio of the liquid crystal display by the spacer can be prevented, and the reduction of the liquid crystal dropping amount found in the column spacer having poor recovery characteristics can be overcome. In addition, due to the step of the color filters having different thicknesses, the spacers are also disposed under the color filters having the thin thickness. Since the spacer disposed under the color filter having such a thin thickness contributes to dispersing the external impact, the liquid crystal display according to the present invention may have improved smear resistance.

Claims (20)

A first substrate on which sustain electrodes and thin film transistors are formed; A second substrate having a light shielding film pattern and spaced apart from the first substrate by a predetermined cell gap; First and second color filters disposed between the first substrate and the second substrate; And A first spacer and a second spacer disposed on the first and second color filters, respectively, between the first substrate and the second substrate; The first color filter is thicker than the second color filter, And the first and second spacers are selectively disposed in a region where a light blocking layer pattern is formed or in a region where a sustain electrode is formed. The method of claim 1, And the first spacer and the second spacer have the same size and are made of the same material within an error range of 10%. The method of claim 1, Further comprising a third color filter disposed between the first substrate and the second substrate, The first color filter is a blue filter, the second color filter is a red filter, and the third color filter is a green filter, And the third color filter is thinner than the first color filter and thicker than the second color filter. The method of claim 3, wherein Further comprising a third spacer disposed on the third color filter between the first substrate and the second substrate, The third spacer has the same size and is made of the same material within an error range of 10% with the first spacer, The first, second and third spacers are selectively disposed in at least one region between the light shielding film pattern of the first substrate and the second substrate and between the sustain electrode of the first substrate and the second substrate. Liquid crystal display. The method of claim 1, And the first spacer and the second spacer are bead-type spacers including a plurality of aggregated sub-bead spacers. The method of claim 1, The first spacer and the second spacer may be at least one of an acryl organic compound, Teflon, benzocyclobutene (BCB), cytope, and perfluorocyclobutene (PFCB). The liquid crystal display device characterized by the above-mentioned. The method of claim 1, The first and second color filters are formed on the second substrate, The first spacer is disposed on the first color filter between the light shielding film pattern of the first substrate and the second substrate, And the second spacer is disposed on the second color filter between the light blocking film pattern of the first substrate and the second substrate. The method of claim 1, The first and second color filters are formed on the first substrate, The first spacer is disposed between the light shielding pattern and the first color filter. And the second spacer is disposed between the light blocking layer pattern and the second color filter. Forming thin film transistors on a first substrate; Forming a light shielding film pattern on the second substrate; Forming first, second and third color filters disposed on the second substrate and extending above the light shielding pattern; Selectively disposing first and second spacers in predetermined regions above the first and third color filters, respectively; Bonding the first substrate and the second substrate to each other; And Injecting a liquid crystal between the first substrate and the second substrate, And the first color filter is formed thicker than the third color filter. The method of claim 9, And the first spacer is formed of the same material having the same size within the error range of 10% with the second spacer. The method of claim 9, The first, second and third color filters are formed of blue, green and red filters, respectively. And the second color filter is thinner than the first color filter and thicker than the third color filter. The method of claim 9, The forming of the first and second spacers may include transferring bead-shaped spacers arranged in a predetermined arrangement onto a first color filter and a third color filter of the second substrate using a predetermined transfer device. Method of manufacturing a liquid crystal display comprising a. The method of claim 12, The bead-shaped spacer includes a plurality of aggregated sub-bead spacers, wherein the sub-bead spacers are acryl organic compounds, Teflon, benzocyclobutene (BCB), cytop and perfluro A method of manufacturing a liquid crystal display device, characterized in that it is formed of at least one of cyclofluorobutene (PFCB). The method of claim 9, Forming a third spacer between the first substrate and the second color filter, And the third spacer is formed at the same time as the first and second spacers, and is formed of the same material having the same size within an error range of 10% with the first spacer. Forming thin film transistors on a first substrate; Forming first, second and third color filters on the first substrate on which the thin film transistors are formed; Selectively disposing first and second spacers in predetermined regions above the first and third color filters, respectively; Forming a light shielding film pattern on the second substrate; Bonding the first substrate and the second substrate to each other; And Injecting a liquid crystal between the first substrate and the second substrate, And the first color filter is formed thicker than the third color filter. The method of claim 15, And the first spacer is formed of the same material having the same size within the error range of 10% with the second spacer. The method of claim 15, The first, second and third color filters are each formed of a blue, green and red filter, And the second color filter is thinner than the first color filter and thicker than the third color filter. The method of claim 15, The forming of the first and second spacers may include transferring bead-shaped spacers arranged in a predetermined arrangement onto a first color filter and a third color filter of the first substrate using a predetermined transfer device. Method of manufacturing a liquid crystal display comprising a. The method of claim 18, The bead-type spacer includes a plurality of aggregated sub-bead spacers, wherein the sub-bead spacers are acryl organic compounds, Teflon, benzocyclobutene (BCB), cytop and perfluro A method of manufacturing a liquid crystal display device, characterized in that it is formed of at least one of cyclofluorobutene (PFCB). The method of claim 15, Forming the first and second spacers includes forming a third spacer on the second color filter, And the third spacer is formed of the same material having the same size within the error range of 10% with the first spacer.

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