Display device

Disclosed is a display device. The display device includes first and second substrates facing each other, a sealant pattern including a first compound attaching the first and the second substrates together, and a separator pattern within the sealant pattern. The separator pattern includes a second compound chemically reacting with the first compound to block the diffusion of the first compound.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 2006-57096, filed on Jun. 23, 2006, which is herein incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a display device. More particularly, the present invention relates to a display device that may prevent the image quality from being degraded due to contamination.

2. Discussion of the Background

Recent display devices include the liquid crystal display device, plasma display device, organic electroluminescence display device, and the like. These display devices are applied in various devices, such as big screen TVs, notebook computers, and cellular phones.

The above-described display devices include a pair of substrates facing each other. For example, a liquid crystal display device includes two substrates facing each other and a liquid crystal layer provided therebetween. An electric field is applied to the liquid crystals of the liquid crystal layer, and the arrangement of the liquid crystals changes according to the application of the electric field to display the corresponding images.

The region where the image is displayed is defined as a display area, which includes the center portion of the two substrates. A sealant pattern is formed at the edge portion to attach the two substrates together.

The sealant pattern may be formed using a compound including polymer resin. However, while the two substrates are being attached together, the compound included in the sealant pattern may diffuse into the display area. This may contaminate the display area, thereby deteriorating the quality of the image of the display device.

SUMMARY OF THE INVENTION

This invention provides a display device that may maintain a high quality image by preventing contamination of a display area.

The present invention discloses, a display device including a first substrate including a display area, a second substrate facing the first substrate, a sealant pattern arranged on one of the first substrate and the second substrate and outside the display area, the sealant pattern including a first compound, and a separator pattern arranged on one of the first substrate and the second substrate and between the sealant pattern and the display area, the separator pattern including a second compound to chemically react with the first compound to prevent diffusion of the first compound into the display area.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIG. 1is an exploded perspective view of a liquid crystal display device according to an exemplary embodiment of the present invention.

Referring toFIG. 1, the device includes a first substrate100and a second substrate200facing each other, and liquid crystals (not shown) provided between the first substrate100and the second substrate200. A display area DA, in which an image is displayed, is defined on the first substrate100. The display area DA includes the center portion of the first substrate100and excludes the edge portion of the first substrate100.

A plurality of gate lines110and a plurality of data lines140are formed on the first substrate100and define a pixel area PA. The pixel area PA represents a single unit that is used to display the image. Each pixel area PA has the same structure.

Each pixel area PA includes a pixel electrode160and a thin film transistor T. The thin film transistor T includes a gate electrode, a source electrode, and a drain electrode, connected to the gate line110, the data line140, and the pixel electrode160, respectively. The second substrate200includes a common electrode230corresponding to the pixel electrode160.

During the operation of the liquid crystal display device, a gate on signal is applied to the gate line110to turn on the thin film transistor T. In addition, data signals carrying the image information are transmitted through the data line140and applied to the pixel electrode160, and a common voltage is applied to the common electrode230. An electric field according to the voltage difference between the pixel electrode160and the common electrode230causes a change in the arrangement of the liquid crystals to display an image.

The liquid crystal may be exposed to various foreign materials and may be contaminated. When the liquid crystal is contaminated, the quality of the image may deteriorate. One of the contaminants of the liquid crystal may be a sealant pattern300.

The sealant pattern300is formed at the outer portion of the display area DA on the first substrate100. The sealant pattern300also can be formed on the second substrate200corresponding to the exterior portion of the display area DA. The sealant pattern300includes a resin that may be cured by heat or light. The resin couples the first substrate100and the second substrate200together. When the sealant pattern300is cured, a first compound included in the sealant pattern300may diffuse into the display area DA and contaminate the liquid crystal.

In order to prevent contamination of the liquid crystal due to the first compound, a separator pattern400may be formed. The separator pattern400is formed on one of the first substrate100or the second substrate200. The separator pattern400functions as a physical barrier between the sealant pattern300and the display area DA to block the movement of the first compound.

The first compound includes an amine-based compound in which a hydrogen atom of ammonia is replaced with a hydrocarbon. The first compound is represented by the chemical formula NH2CO(CH2)nCON2H5(in which n represents an integer greater than or equal to 1). Particularly, the first compound is represented by the following structure of chemical formula 1 or chemical formula 2.

The separator pattern400includes a second compound which chemically reacts with the first compound. The second compound includes an epoxy-based compound that may be formed by polymerizing acryl monomers having an epoxide. The chemical reaction concerning the polymerization is represented by the following reaction equation 1.

In reaction equation 1, the reactant is an acryl monomer including the epoxide, and the product is a polymer obtained through the polymerization reaction. In reaction equation 1, the portion designated by dotted lines represents the epoxide. R and R′ have a structure including one of the functional groups of an amide functional group (—NH—CO—), an ester functional group (—CO—O—), an ether functional group (—O—), a sulfide functional group (—S—), a sulfoxide functional group (—SOO—), a hydroxide functional group (—OH), a halide functional group (—F, —Cl, —Br, —I), an imide functional group (—CO—N—CO—), an aza functional group (—N—), an amine functional group (—NH2—), an azo functional group (—N═N—), an aldehyde functional group (—CO—H), a carboxyl functional group (—CO—), an anhydride functional group (—CO—O—CO—) and an urea functional group (—NH—CO—NH—).

In particular, one of a chemically stable amide functional group (—NH—CO—), ester functional group (—CO—O—), ether functional group (—O—), sulfide functional group (—S—), or carboxyl functional group (—CO—) is preferred.

As described above, when the first compound of the sealant pattern300and the second compound of the separator pattern400include the amine-based compound and the epoxy-based compound, respectively, the first and second compounds chemically react according to the chemical reaction of an amine and an epoxide as follows.

When the first compound is represented by chemical formula 1, the chemical reaction of the first and the second compounds is represented by the following reaction equation 2.

When the first compounds is represented by chemical formula 2, the chemical reaction of the first and the second compounds is represented by the following reaction equation

As illustrated in reaction equation 2 and reaction equation 3, a portion or the entire epoxy-based second compound may combine with the amine-based first compound. In reaction equations 2 and 3, a portion (k) of the individual molecules (n) constituting the second polymer compound reacts with the first compound, and the remaining portion (l) thereof does not react with the first compound. The portion of the second compound that reacts with the first compound does not need to continuously be neighboring the first compound. A portion or all of a neighboring portion reacts with the first compound.

During the reaction, the structure of the second compound changes from a cyclic shape to a chain shape, and one hydrogen included in the amine of the first compound combines with oxygen included in the epoxy-based second compound.

Through the above described chemical reaction, the first compound and the second compound combine and may prevent diffusion of the compounds into the display area DA. As illustrated in the reaction equations 2 and 3, since no additional product is generated, there is no contamination of the liquid crystal from an additional product of the chemical reaction

Therefore, the contamination of the liquid crystal within the display area DA may be prevented by physically and chemically blocking the contaminating materials from the sealant pattern300by means of the separator pattern400, thereby improving the quality of the image of the liquid crystal display device.

FIG. 2is a schematic planar view ofFIG. 1. Referring toFIG. 2, the liquid crystal display device includes a first substrate100and a second substrate200facing each other and a display area DA defined on the first substrate100. A sealant pattern300is formed along the edge portion of the first substrate100forming a closed loop. A separator pattern400is formed between the display area DA and the sealant pattern300. The separator pattern400forms a closed loop within the sealant pattern300, and the contaminating materials (designated by arrows) from the sealant pattern300are blocked by the separator pattern400to prevent the diffusion of the contaminating materials into the display area DA.

Referring toFIG. 3, a gate electrode111of a thin film transistor T is formed on a predetermined region of the first substrate100. A gate insulating layer120is formed on the gate electrode111to substantially cover the entire surface of the first substrate100. A semiconductor pattern130is formed on the gate insulating layer120and overlapping the gate electrode111. A source electrode141and a drain electrode142are formed facing each other on the semiconductor pattern130. The semiconductor pattern130includes an active pattern131and an ohmic contact pattern132. The active pattern131forms a channel during the operation of the thin film transistor T, and the ohmic contact pattern132is separated along the source electrode141and the drain electrode142.

A passivation layer150is formed on the thin film transistor T to substantially cover the entire surface of the first substrate100. A pixel electrode160is formed on the passivation layer150. A contact hole150his formed in the passivation layer150to expose the drain electrode142. The pixel electrode160is electrically connected to the drain electrode142through the contact hole150h.

A light shielding layer pattern210and a color filter220are formed on the second substrate200. The color filter220is formed at the region corresponding to the pixel area PA. The color filter220may be a red color filter, green color filter, or blue color filter, which are the three primary colors of light, in order to display a color image. The light shielding layer pattern210shields the transmission of light at the exterior region of the pixel area PA. A common electrode230is formed on the light shielding layer pattern210and the color filter220to face the pixel electrode160. A spacer500is formed on the common electrode230to keep a predetermined distance between the first substrate100and the second substrate200.

A sealant pattern300and a separator pattern400are arranged at the edge portion of the first substrate100and the second substrate200. The sealant pattern300is formed on the first substrate100and the upper surface portion thereof contacts the second substrate200. The separator pattern400is formed on the second substrate200and the lower portion thereof is separated from the first substrate100. The separator pattern400may be formed on the first substrate100and the upper portion thereof is separated from the second substrate200. Through the separated portion, the contaminating materials generated from the sealant pattern may be permitted to move, however, the diffusion of the contaminating materials into the display area DA is blocked because of a chemical reaction with a compound included in the separator pattern400. If the gap between the separator pattern400and the first substrate100is too large, the contaminating materials may diffuse into the display area DA in spite of the chemical blocking by the separator pattern400. Therefore the gap between the separator pattern400and the first substrate100is required to have an upper limit, preferably the gap may be about 10% or less of the distance between the first substrate100and the second substrate200.

FIG. 4is a schematic planar view of a liquid crystal display device according to another exemplary embodiment of the present invention. The detailed description of the common portion with the previous explanation will be omitted in the following description.

Referring toFIG. 4, a first substrate100on which a display area DA is defined and a second substrate200facing the first substrate100are provided, and a sealant pattern300is formed along the edge portion of the first substrate100. A separator pattern400is formed between the display area DA and the sealant pattern300to block the contaminating material (designated by arrows).

The sealant pattern300seals the space between the first substrate100and the second substrate200and forms a closed loop to receive the liquid crystal therein. The separator pattern400corresponds to the sealant pattern300, however, the separator pattern400does not form a closed loop. Accordingly, separator pattern400may include discrete segments positioned to form a rectangular shape. The contaminating material (designated by arrows) from the sealant pattern300is blocked by the separator pattern400and does not diffuse into the display area DA. At the opened portion between two segments of the separator pattern400, the contact area of the contaminating material with the separator pattern400increases and thus the rate of the chemical reaction to prevent the diffusion of the contaminating material increases.

Referring toFIG. 5, a gate electrode111of a thin film transistor T, a gate insulating layer120, a semiconductor pattern130, a source electrode141, a drain electrode142, a passivation layer150, and a pixel electrode160are formed on the first substrate100.

A light shielding layer pattern210, a color filter220, a common electrode230, and a spacer500are formed on the second substrate200.

The sealant pattern300and the separator pattern400are formed at the edge portion of the first substrate100and the second substrate200. The sealant pattern300is formed on the first substrate100, and the upper surface portion thereof contacts the second substrate200. The separator pattern400is formed on the first substrate100, and the upper surface portion thereof is separated from the second substrate200. The separator pattern400may be formed on the second substrate200, and the lower surface portion thereof is separated from the first substrate100. The gap between the separator pattern400and the second substrate200may be about 10% or less of the distance between the first substrate100and the second substrate200.

A concavo-convex shape401is formed on the upper surface portion of the separator pattern400. The surface area of the upper surface portion of the separator pattern400increases due to the concavo-convex shape401. Due to the increased surface area, the contact area of the contaminating material from the sealant pattern300with the separator pattern400increases. As a result, the rate of the chemical reaction to effectively prevent the diffusion of the contaminating material increases. In order to further increase the contact area of the contaminating material with the separator pattern400, the concavo-convex shape401also can be formed at the side surface of the separator pattern400that faces the sealing pattern300.

Referring toFIG. 6A, the light shielding layer pattern210and the color filter220are formed on the second substrate200. The light shielding layer pattern210may be formed by coating a light shielding layer including a photoresist component on the second substrate200and then patterning the light shielding layer. The patterning is formed during an exposing and a developing process. The light shielding layer coated at the region corresponding to the pixel area is removed by the developing process.

The color filter220may be formed by coating a color photoresist layer on the second substrate200and then patterning the coated color photoresist layer. The color filter220fills the removed area of the light shielding layer that is removed at the patterning of the light shielding layer. The patterning with respect to the color photoresist layer is implemented three times for the red/green/blue color filters.

Referring toFIG. 6B, the common electrode230is formed on the color filter220. The common electrode230may be formed by depositing a transparent conductive layer of indium zinc oxide (IZO) or indium tin oxide (ITO) on the color filter220. An over coating layer (not shown) can be additionally formed between the color filter220and the common electrode230to planarize the surface of the second substrate200, if needed.

Referring toFIG. 6C, a material layer450including a photoresist component is coated on the common electrode230. The material layer450may include a polymer obtained by polymerizing acryl monomers having an epoxide. The polymer can be represented by the following chemical formula 3 as described above in reaction equation 1.

Next, an exposing process with respect to the material layer450is implemented. During the exposing process, a photo mask600exposing a predetermined region of the material layer450is utilized. The photo mask600includes a light transmitting region610and a light shielding region620.

Referring toFIG. 6D, a developing process for the exposed material layer450is described. When the material layer450includes a negative-type photoresist component, an unexposed portion is removed during the exposing process. On the contrary, when the material layer450includes a positive-type photoresist component, an exposed portion is removed during the exposing process. InFIG. 6D, the material layer450is formed by using the negative-type component. Through the developing process, the material layer450is patterned to simultaneously form the separator pattern400and the spacer500.

Referring toFIG. 6Ea process for the first substrate100is carried out apart from the process for the second substrate200. On the first substrate100, a thin film transistor T including a gate electrode111, a semiconductor pattern130, a source electrode141, and a drain electrode142is formed. On the thin film transistor T, a passivation layer150is formed. On the passivation layer150, a pixel electrode160is formed.

Referring toFIG. 6F, a sealant pattern300is arranged at the edge portion of the first substrate100. The first substrate100and the second substrate200are arranged to face each other. When the sealant pattern300is cured by heat or light and the first substrate100and the second substrate200are attached together, the manufacture of the liquid crystal display panel is completed.

Through the above described process, a separator pattern400and a spacer500are formed simultaneously. Therefore, a separate process to form the separator pattern400can be omitted to improve process efficiency.

FIG. 7A,FIG. 7B,FIG. 7C, andFIG. 7Dare cross-sectional views showing a manufacturing process of the liquid crystal display device ofFIG. 5.

Referring toFIG. 7A, the thin film transistor T including the gate electrode111, the semiconductor pattern130, the source electrode141, and the drain electrode142is formed on the first substrate100. The passivation layer150is formed on the thin film transistor T, and the pixel electrode160is formed on the passivation layer150.

On the whole surface of the first substrate100, a material layer450is formed to cover the passivation layer150and the pixel electrode160. The material layer450may include a polymer material obtained by polymerizing acryl monomers having an epoxide and represented by chemical formula 3.

An exposing process with respect to the material layer450is the carried out. A photo mask600′ is used during the exposing process, and the photo mask600′ includes a light transmitting region610′ and a semi-light transmitting region630′. At the semi-light transmitting region630′ a portion of the light transmits through the semi-light transmitting region630′ according to the positions of the corresponding region of the material layer450. As the photo mask600′, a half tone mask or a slit mask may be used.

FIG. 7Bshows a developing process with respect to the exposed material layer450is described. In the material layer450, a positive type or a negative type photoresist component is included. As illustrated inFIG. 7B, when the photoresist is the positive type, the completely exposed portion is removed, and a separator pattern400is formed by the remaining portion. The remaining portion of the material layer450is partially exposed by the semi-light transmitting region630′. As a result, a concavo-convex shape401is formed.

The concavo-convex shape can be formed at the side surface of the separator pattern400as well as on the upper surface thereof. After patterning the material layer450and forming the separator pattern400, the side portion may be formed into the concavo-convex shape.

Referring toFIG. 7C, a light shielding layer pattern210, a color filter220, a common electrode230, and a spacer500are formed on the second substrate200.

Referring toFIG. 7D, a sealant pattern300is coated at the edge portion of the first substrate100, and the first substrate100and the second substrate200are arranged so that they face each other. The sealant pattern300is cured by heat or light, and the first substrate100and the second substrate200are coupled together to complete the manufacturing of the liquid crystal display panel.

According to the above-described process, the spacer500and the separator pattern400are separately formed using different materials. At this time, the spacer500can be formed by using a material having a high elasticity so that the spacer500has elasticity, and the distance between the first substrate100and the second substrate200may be maintained.

As described above, since the separator pattern is formed using a material having a chemical reactivity with the sealant pattern, the separator pattern blocks the contaminating material physically and chemically, thereby providing a display device that may have high quality images.