Display panel, and frame sealant application device and application method thereof

A display panel, a sealant coating device and a method for sealant coating are provided. The display panel includes a display area and a peripheral area and further includes oleophobic sealant provided in the peripheral area on a side near the display area and hydrophobic sealant provided in the peripheral area on a side away from the display area and surrounding the oleophobic sealant.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a U.S. National Stage Application under 35 U.S.C. § 371 of International Patent Application No. PCT/CN2018/077411 filed on Feb. 27, 2018, which claims priority to Chinese patent application No. 201710194136.4 filed on Mar. 28, 2017, DISPLAY PANEL, AND FRAME SEALANT APPLICATION DEVICE AND APPLICATION METHOD THEREOF which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

Embodiments of the present disclosure relate to a display panel, a sealant coating device and a method for sealant coating.

BACKGROUND

As an important material used for production of liquid crystal display panels, the sealant is operable to bond a lower substrate and an upper substrate firmly together and protect the entire overlay of various circuit wiring on the lower substrate, i.e. the substrate on which thin film transistors (TFTs) are arranged in an array, very well from corrosion.

SUMMARY

Embodiments of the present disclosure provide a display panel, a sealant coating device and a method for sealant coating.

Embodiments of the present disclosure employ the following technical proposals.

In a first aspect, a display panel is provided by embodiments of the present disclosure, comprising: a display area and a peripheral area; an oleophobic sealant provided in the peripheral area on a side near the display area; and a hydrophobic sealant provided in the peripheral area on a side away from the display area and surrounding the oleophobic sealant.

For example, the oleophobic sealant comprises a matrix sealant material and particles dispersed in the matrix sealant material, the dispersed particles having oleophobic first functional groups on their surfaces.

For example, the oleophobic first functional group comprises at least one of —OH, —CHO, —COOH and —NH2.

Optionally, the hydrophobic sealant comprises a matrix sealant material and particles dispersed in the matrix sealant material, the dispersed particles having hydrophobic second functional groups on their surfaces.

For example, the hydrophobic second functional group comprises at least one of —CnH(2n+1), —CH═CH2, —C6H5, a halogen atom and —NO2, where n is a positive integer.

Optionally, the material of the dispersed particles includes any of silicon dioxide, silicon and aluminum oxide (Al2O3).

Optionally, the dispersed particles are in a spherical shape.

In a second aspect, a device for sealant coating is provided by an embodiment of the present disclosure, comprising a first sealant supplying container, a second sealant supplying container and a spray head. The spray head comprises a first accommodation chamber, a second accommodation chamber and a slit opening. The first accommodation chamber and the second accommodation chamber are in intercommunication at the area near the slit opening. The first sealant supplying container and the second sealant supplying container are in communication with ends of the first accommodation chamber and the second accommodation chamber away from the slit opening and configured to contain oleophobic sealant and hydrophobic sealant, respectively.

Optionally, the device for sealant coating further comprises a pressure controller to control the feeding amount of sealant from the first sealant supplying container and/or the second sealant supplying container.

In a third aspect, a coating method using the device for sealant coating is provided in an embodiment of the present disclosure, comprising: allowing a side of the second accommodation chamber of the spray head to face the display area of the first substrate in the display panel; allowing a side of the first accommodation chamber of the spray head to face away from the display area; and controlling the spray head to spray the sealant along the peripheral area of the first substrate so as to form the hydrophobic sealant in the peripheral area and on the side near the display area and form the oleophobic sealant in the peripheral area on the side away from the display area and surrounding the hydrophobic sealant.

DETAILED DESCRIPTION

Technical solutions of the embodiments will be described in a clearly and fully understandable way in connection with the drawings related to the embodiments of the disclosure. It is apparent that the described embodiments are just a part but not all of the embodiments of the disclosure. Based on the described embodiments herein, a person of ordinary skill in the art can obtain other embodiment(s), without any creative work, which shall be within the scope of the disclosure.

Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms, such as “first,” “second,” or the like, which are used in the description and the claims of the present application, are not intended to indicate any sequence, amount or importance, but for distinguishing various components. Also, the terms, such as “comprise/comprising,” “include/including,” or the like are intended to specify that the elements or the objects stated before these terms encompass the elements or the objects and equivalents thereof listed after these terms, but not preclude other elements or objects. The terms, “on,” “under,” “a side,” “another side,” or the like are only used to indicate relative position relationship, and when the absolute position of the object which is described is changed, the relative position relationship may be changed accordingly.

Structural dimensions involved in embodiments of the present disclosure range generally in order of magnitude from nanometer to millimeter (nm˜mm), and for purpose of clear explanation, dimensions of structures in the accompanying drawings of embodiments of the present disclosure are exaggerated and not representative of actual dimensions.

Traditional sealant is mainly composed of resin and initiator. As shown inFIG. 1, a coating process for the sealant includes spray the sealant onto the peripheral area of the lower substrate using spray head, dripping liquid crystals onto the display area defined by the sealant, assembling the lower substrate with an upper substrate, pre-curing the sealant using the UV (Ultraviolet) irradiation, and finally thermo-curing the sealant (now shown inFIG. 1).

It has been noticed by the present inventors that the sealant is increasingly close to the display area as the bezels of display products are designed to be increasingly narrow. After assembling of the lower and upper substrates, the liquid crystal molecules may diffuse to spread out due to their fluidity. If the liquid crystal molecules come into contact with the sealant without being pre-cured by UV, the sealant may be punctured and the liquid crystal may be contaminated, leading to image flickering (FLK) during display OF the liquid crystal display panel and thus affecting display quality of the panel. Moreover, as bezels of display products are becoming narrower, the coating width of sealant is becoming smaller and moisture may intrude through the sealant to corrode circuit wiringS on the TFT substrate during subsequent usage, leading to abnormal display.

As shown inFIG. 2, an embodiment of the present disclosure provides a display panel01including a display area (indicated by A in the figure) and a peripheral area (indicated by S in the figure). The display panel01includes an oleophobic sealant10disposed in the peripheral area on the side near the display area and a hydrophobic sealant20disposed in the peripheral area on the side away from the display area and surrounding the oleophobic sealant10.

It is to be noted that the display panel01further includes a first substrate and a second substrate disposed oppositely to each other, between which the above-mentioned oleophobic sealant10and the hydrophobic20are located. The first and second substrates may act respectively as an array substrate and a color filter substrate, or as color filter on array (COA) substrate and a cover substrate, and vice versa.

By way of example, as shown inFIG. 3, the array substrate or COA substrate (with structures such as chips bonded onto the side edge of its bezel area) is coated with the oleophobic sealant10and the hydrophobic sealant20and then assembled with the color filter substrate or the cover substrate.

For better comprehension of the above-mentioned oleophobic sealant10and hydrophobic sealant20provided in the embodiment of the present disclosure, the concept of “contact angle” will be introduced and explained in the following text. When a liquid drop is formed and stabilized on a solid surface, a contact angle θ of some magnitude will be formed by the liquid drop at the meeting line of the gas, liquid and solid phases.

As shown inFIG. 4, the term “oleophobic sealant” means that this type of sealant has relatively higher repellence against oleiferous liquids, and drops of oleiferous liquids may have contact angels larger than 90° and it is hardly for them to spread out on the surface of the sealant. Relatively, the sealant has relatively higher affinity for water and aqueous liquids with similar dissolvability, so that the aqueous liquids may have contact angles smaller than or equal to 90° and it is easily for them to spread out on the surface of the sealant. As a result, the above-mentioned oleophobic sealant may also be referred to as hydrophilic sealant.

Similarly, as shown inFIG. 5, the term “hydrophobic sealant” means that this type of sealant has relatively higher repellence against water and aqueous solutions of similar dissolvability, so that drops of aqueous liquids have contact angles larger than 90° and it is hardly for them to spread out on the surface of the sealant. Relatively, the sealant has relatively higher affinity for oleiferous liquids, so that the oleiferous liquids may have contact angles smaller than or equal to 90° and it is easily for them to spread out on the surface of the sealant. As a result, the above-mentioned hydrophobic sealant may also be referred to as oleophilic sealant.

In the above-mentioned display panel provided in the embodiment of the present disclosure, two types of sealants are disposed in the peripheral area of the display panel. The inner layer, i.e. the layer near the display area, is the oleophobic sealant10. Since liquid crystals commonly used in liquid crystal displays including biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester type liquid crystal and the like, are oleiferous and have no or very low solubility in water, the oleophobic sealant10near the display area may reduce the degree of contact between the liquid crystals and the oleophobic sealant without being completely cured, reduce the possibility of being punctured, protect the liquid crystals from being contaminated, reduce defects, such as FLK during display of the liquid crystal display panel, and guarantee display quality. The outer layer, i.e. the layer away from the display area and surrounding the oleophobic sealant10, is the hydrophobic sealant20and can prevent moisture from intruding through the sealant to cause corrosion during subsequent usage.

Furthermore, for example and as shown inFIG. 3, the above-mentioned oleophobic sealant10includes matrix sealant material100and particles101dispersed in the matrix sealant material100with the dispersed particles101having oleophobic first functional groups (not shown in the figure) on their surfaces. The above-mentioned hydrophobic sealant20includes matrix sealant material200and particles201dispersed in the matrix sealant material200with the dispersed particles201having hydrophobic second functional groups (not shown in the figure) on their surfaces.

It is to be noted that the above-mentioned matrix sealant material100and the matrix sealant material200may include, but not limited to, resin materials. There are many resin materials to choose, such as acrylic resin, epoxy resin, bisphenol A epoxy resin, polyvinyl butyral resin, diethylene glycol monobutyl ether acetic ester, urethane resin containing carboxy groups and the like. In addition, the above-mentioned oleophobic sealant10or the hydrophobic sealant20may also include initiator and the like, in this regard, traditional technologies may be used and embodiments of the present disclosure are not limited in any way.

The so called “particle” refers to a geometric body within a dimensional range and having a particular shape. Herein, dimensions of a particle generally range in order of magnitude from nanometer to millimeter. Therefore, the above-mentioned dispersed particles101or dispersed particles201refer to particles that have relatively small dimensions and may have many shapes, for example, but not limited to, a spherical shape.

The dispersed particles (e.g. silicon balls) in the sealant function to provide some thickness support so as to reduce volume shrinkage of the sealant after being cured, and at the same time, to increase the viscosity of the sealant before being cured, so as to reduce sealant flowage, facilitating stirring and/or screen printing. In addition to having the function described above, the dispersed particles in the above-mentioned oleophobic sealant10or hydrophobic sealant20provided in the embodiment of the present disclosure also act as carriers for functional surface modification of functional groups.

For example, the material of the above-mentioned dispersed particles may include any one of silicon dioxide, silicon, aluminum oxide (Al2O3), and the particles may have a spherical shape to facilitate particle dispersing and functional group grafting.

That is, as shown in the view (a) inFIG. 6, an oleophobic modifying layer consisting of the oleophobic first functional groups is formed on the surface of the dispersed particle101, resulting in a shell-core structure.

Similarly, as shown in view (b) inFIG. 6, a hydrophobic modifying layer consisting of the hydrophobic second functional groups is formed on the surface of the dispersed particle201, resulting in a shell-core structure.

It is to be noted that the above-mentionedFIG. 6is only provided to indicate that a dispersed particle101has oleophobic first functional groups on its surface, and the first functional groups may be grafted on part of or the entire surface of the dispersed particle101, which includes, but not limited to, the case indicated schematically in view (a) ofFIG. 6) where the first functional groups cover the entire surface and thus form an oleophobic modifying layer.

In the same way, the above-mentionedFIG. 6is provided to indicate that a dispersed particle201has the hydrophobic second functional groups on its surface, and the second functional groups may be grafted on part of or the entire of the surface of the dispersed particle201, which includes, but not limited to, the case indicated schematically in the view (b) inFIG. 6where the second functional groups cover the entire surface and thus form a hydrophobic modifying layer.

In this way, the surface modifying layer has a thickness in nanometers, no significant effect will be exerted on the dimensions of the dispersed particles and the line width of TFT wiring in the display panel will not be additionally increased, resulting in negligible effect on the width of the bezel of the display panel.

Furthermore, for example, the above-mentioned oleophobic first functional groups include at least one of a hydroxyl group (—OH), an aldehyde group (—CHO), a carboxyl group (—COOH) and an amino group (—NH2).

The above-mentioned hydrophobic second functional group includes at least one of an alkyl group (—CnH(2n+1), where n is a positive integer), a vinyl group (—CH═CH2), a phenyl ring group (—C6H5), a halogen atom (including fluorine (F), chlorine (Cl), bromine (Br), iodine (I) and astatine (At), generally symbolized as —X) and a nitro group (—NO2).

The following embodiment is provided to illustrate the process of modification using the above-mentioned oleophobic or hydrophobic functional groups.

Modification by the oleophobic first functional groups: nano-particles of SiO2are used as the dispersed particles101in the oleophobic sealant10. During the grafting process for the functional surface modification, 10 grams of nano-particles of SiO2are dispersed in 50 ml of HCl solution (the concentration of HCl in water is 10% volume/volume) contained in a 500 ml beaker. After uniformly stirring for 1 hour (h), the solid resultant is separated from the HCl solution and the SiO2nano-particles are washed several times by deionized water. The solid resultant is placed under a vacuum condition to evaporate the solvent on the surface, so that oleophobic, i.e. hydrophilic, activated SiO2nano-particles (SiO2—OH) are obtained with the above-mentioned modification method, which has a yield of about 90%.

Modification by the hydrophobic second functional groups: nano-particles of SiO2are used as the dispersed particles201in the hydrophobic sealant20. During the grafting process for the functional surface modification, 20 ml dehydrated alcohol is placed into a dry beaker, a given amount of dry nano-particles of SiO2are put into the dehydrated alcohol; ultrasonic dispersion is performed on the mixture for 15 min, which is then placed into a 250 ml three-neck flask. Dehydrated alcohol solution containing a given amount of silane coupling agent (having a molecular formula of C10H22O4Si, generally marked as KH-570) is then put into the three-neck flask, which is heated to a certain temperature in water bath to achieve reflux reaction for 5 h. The solid resultant is centrifugally separated from the liquid, washed 3 times by dehydrated alcohol, and then placed into an oven at 100° C. to be dried for 10 h, resulting in nano-particles of SiO2modified by silane coupling agent. During this process, the hydrophobic functional groups for grafting on the surfaces are mainly alkyl groups and vinyl groups.

Based on the description above, as shown inFIG. 7, an embodiment of the present disclosure also provides a sealant coating device, which includes a first sealant supplying container03(e.g. a sealant barrel), a second sealant supplying container (e.g. a sealant barrel) and a spray head05. The spray head05includes a first accommodation chamber51, a second accommodation chamber52and a slit opening53. The first and second accommodation chambers52,53are in intercommunication at the area near the slit opening53(resulting in a hybrid gun head as shown in the dashed-line box). The first and second sealant supplying container03,04are respectively in communication with the ends of the first and second accommodation chambers51,52away from the slit opening53. The first sealant supplying container03is used to contain the oleophobic sealant and the second sealant supplying container04is used to contain the hydrophobic sealant.

Here, the first and second accommodation chambers51,52are in intercommunication with each other at the area near the slit opening53, so that a hybrid gun head is formed as shown in the dashed-line box, which can coat two types of sealants at the same time, simplifying the technical process.

The above-mentioned device for sealant coating has a simplified structure and needs relatively small modification to the fabrication process of an existing coating device. For example, the above-mentioned device may be realized by replacing a conventional single spray head with a spray head having the hybrid gun head and adding an additional sealant barrel, which is easy to carry out.

Furthermore, for example, as shown inFIG. 7, the above-mentioned device for sealant coating also includes a pressure controller to control the feeding amount of sealant from the first sealant supplying container and/or the second sealant supplying container.

Based on the description above, an embodiment of the present disclosure also provides a coating method with the above-mentioned device for sealant coating. The coating method includes: allowing a side of the second accommodation chamber of the spray head to face the display area of the first substrate (e.g. the array substrate or COA substrate as shown inFIG. 3) in the display panel; allowing a side of the first accommodation chamber of the spray head to face away from the display area; and controlling the spray head to spray the sealant along the peripheral area of the first substrate so as to form the hydrophobic sealant in the peripheral area and on the side near the display area and form the oleophobic sealant in the peripheral area on the side away from the display area and surrounding the hydrophobic sealant.

In the above-mentioned display panel provided in the embodiments of the present disclosure, two types of sealants are disposed in the peripheral area of the display panel. The inner layer, i.e. the layer near the display area, is the oleophobic sealant. Since liquid crystals commonly used in liquid crystal display mainly includes biphenyl liquid crystal, phenylcyclohexane liquid crystal, ester type liquid crystal and the like, which are oleiferous and have no or very low solubility in water, the oleophobic sealant near the display area may reduce the degree of contact between the liquid crystals and the oleophobic sealant before the sealant is not completely cured, reduce the possibility of being punctured, protect the liquid crystals from being contaminated, reduce defects, such as FLK during display of the liquid crystal display panel, and guarantee the display quality. The outer layer, i.e. the layer away from the display area and surrounding the oleophobic sealant, is the hydrophobic sealant and can prevent moisture from intruding through the sealant to cause corrosion during subsequent usage.

It can be appreciated by those skilled in the art that structural composition of the above-mentioned oleophobic sealant and/or hydrophobic sealant and components of the device for sealant coating provided in embodiments of the present disclosure are not limited by the structures shown schematically in all of the accompanying drawings in the present disclosure, which are provided only to clearly depict structures associated with the inventive points. Those structures unrelated with the inventive points may be implemented with conventional structures and are not or only partially shown in the accompanying drawings.

The described above are only exemplary embodiments of the present disclosure, and the present disclosure is not intended to be limited thereto. For one of ordinary skill in the art, various changes and alternations may be readily contemplated without departing from the technical scope of the present disclosure, and all of these changes and alternations shall fall within the scope of the present disclosure.