Patent Description:
With the development of multimedia, display devices are becoming increasingly important. Accordingly, various display devices such as liquid crystal displays and organic light emitting diode displays are being developed.

Display devices such as liquid crystal displays and organic light emitting diode displays may display images due to transmission of light. In particular, the transmittance of light may affect the display quality (e.g., luminance) of a display device. Thus, a display device may at least partially include a transparent element, for example, a glass element. Reference is made to <CIT>.

To form a multi-stack structure by bonding a plurality of transparent members, a bonding method using a sealant which is a liquid or ointment-type adhesive or a bonding method using a glass frit or powdered glass may be utilized.

In the sealant bonding, a first glass member and a second glass member may be bonded to each other by applying a liquid or ointment-type sealant material between the first glass member and the second glass member and then curing the sealant material.

In the glass frit/powdered glass bonding, the first glass member and the second glass member may be bonded to each other by applying a glass frit/powdered glass material between the first glass member and the second glass member and then melting and curing the glass frit/powdered glass material.

The present invention relates to a display device in which the area occupied by a cell seal is reduced.

Aspects of the present invention also provide a display device with improved bonding strength.

Aspects of the present invention also provide a method of manufacturing a display device in which the area occupied by a cell seal is reduced.

Aspects of the present invention also provide a method of manufacturing a display device with improved bonding strength.

However, aspects of the present invention are not restricted to the one set forth herein. The above and other aspects of the present invention will become more apparent to one of ordinary skill in the art to which the present invention pertains by referencing the detailed description of the present invention given below.

In addition, the display device may further include a first driver integrated circuit which is disposed in the non-display area, wherein the frit seal may be disposed between the display area and the first driver integrated circuit.

In addition, the contact area may have a width of about <NUM> µm to about <NUM> µm.

In addition, the bonding filament may at least partially overlap the contact area.

In addition, the bonding filament may have a width of about <NUM> ,um to about <NUM> µm.

In addition, the second substrate may further include inner sidewalls which connect the recessed area and the contact area, wherein an opening may be defined by the inner sidewalls, the recessed area and the first substrate, and the frit seal may fill the opening.

In addition, the display device may further include a middle area which is disposed between the recessed area and the contact area and has a different refractive index from that of the recessed area.

In addition, the middle area may have a width of about <NUM> µm to about <NUM> µm.

In addition, the non-display area may include an upper non-display area disposed on an upper side of the display area, a lower non-display area disposed on a lower side of the display area, a left non-display area disposed on a left side of the display area, and a right non-display area disposed on a right side of the display area.

In addition, the bonding filament may be disposed over the upper non-display area, the left non-display area and the right non-display area, and the frit seal may be disposed in the lower non-display area.

In addition, the display device may further include a first driver integrated circuit disposed in the upper non-display area and a second driver integrated circuit disposed in the lower non-display area, wherein the frit seal may include a first sub-frit seal and a second sub-frit seal, wherein the first sub-frit seal may be disposed between the first driver integrated circuit and the display area, and the second sub-frit seal may be disposed between the second driver integrated circuit and the display area.

In addition, the bonding filament may include a first sub-bonding filament and a second sub-bonding filament, wherein the first sub-bonding filament may be disposed in the left non-display area, and the second sub-bonding filament may be disposed in the right non-display area.

In addition, the bonding filament may include a central portion and a peripheral portion disposed outside the central portion, wherein the central portion and the peripheral portion may have different refractive indices.

In addition, the display device may further include one or more insulating films which are disposed on the first substrate, wherein the bonding filament may pass through the insulating films to connect the contact area and the first substrate.

In addition, a distance from a surface of the contact area to a surface of the recessed area may be greater than or equal to a height of an organic light emitting diode.

According to another aspect of the present invention, there is provided a method of manufacturing a display device according to claim <NUM>.

In addition, the laser beam may be a femtosecond laser beam having a pulse width of about <NUM> femtoseconds to about <NUM> femtoseconds.

In addition, a focus of the laser beam may be set inside the first substrate, and a depth of focus may be about -<NUM> µm to less than about <NUM> µm.

In addition, the focus of the laser beam may be set inside the second substrate, and the depth of focus may be about <NUM> µm to less than about <NUM> µm.

In addition, one or more insulating films may be formed on the first substrate, and the method may further include removing the insulating films, wherein the contact area may contact a part of the first substrate from which the insulating films have been removed.

The details of other embodiments are included in the detailed description and the drawings.

According to aspects of the present invention, the area occupied by a cell seal is reduced. Thus, a display device having a narrow bezel can be implemented.

In addition, a display device with improved bonding strength between a upper substrate and a lower substrate can be implemented.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the specification.

Features of the inventive concept and methods of accomplishing the same may be understood more readily by reference to the following detailed description of embodiments and the accompanying drawings.

It will be understood that when an element or layer is referred to as being "on", "connected to" or "coupled to" another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on", "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the inventive concept.

Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

<FIG> is a layout view of a display device according to an embodiment. <FIG> is a cross-sectional view taken along line I-I' of <FIG>. <FIG> is a partial plan view of the display device of <FIG>. <FIG> is a cross-sectional view taken along line II-II' of <FIG>. <FIG> is a cross-sectional view taken along line III-III' of <FIG>. <FIG> is a cross-sectional view taken along line IV-IV' of <FIG>.

Referring to <FIG>, the display device according to the embodiment includes a first substrate <NUM>, a second substrate <NUM>, and a cell seal CS.

In an embodiment, the first substrate <NUM> may include a material such as glass, quartz, or polymer resin. Here, the polymer material may be polyethersulphone (PES), polyacrylate (PA), polyarylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terepthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide (PI), polycarbonate (PC), cellulose triacetate (CAT), cellulose acetate propionate (CAP), or a combination of these materials.

The first substrate <NUM> includes a display area DA and a non-display area NDA.

The display area DA is defined as an area that displays an image. A plurality of pixels PX for realizing an image may be disposed in the display area DA.

The non-display area NDA is disposed outside the display area DA and defined as an area that does not display an image. The non-display area NDA surrounds the display area DA in an embodiment. In <FIG>, the non-display area NDA surrounds the display area DA. However, the present invention is not limited to this case. In an embodiment, the non-display area NDA may be disposed adjacent to only a side or the other side of the display area DA or may be disposed on each of both sides of the display area DA.

For ease of description, different parts of the non-display area NDA will be referred to by different terms. In an embodiment, the non-display area NDA may include an upper non-display area NDA_U disposed on an upper side of the display area DA in <FIG>, a lower non-display area NDA_D disposed on a lower side of the display area DA, a left non-display area NDA_L disposed on a left side of the display area DA, and a right non-display area NDA_R disposed on a right side of the display area DA. In addition, the non-display area NDA may include a first corner non-display area NDA C1, a second corner non-display area NDA_C2, a third corner non-display area NDA_C3, and a fourth corner non-display area NDA_C4 disposed at four corners, respectively.

In an embodiment, a driver integrated circuit IC may be disposed in the non-display area NDA. In <FIG>, a case where the driver integrated circuit IC is disposed in the lower non-display area NDA_D is illustrated as an example.

The driver integrated circuit IC may generate signals necessary for driving the display area DA and transmit the generated signals to the display area DA.

A plurality of first conductive lines <NUM> may be disposed between the driver integrated circuit IC and the display area DA. The first conductive lines <NUM> may electrically connect the driver integrated circuit IC and the display area DA. That is, signals generated by the driver integrated circuit IC may be transmitted to the display area DA via the conductive lines <NUM>.

As described above, a plurality of pixels PX may be arranged in the display area DA. A stacked structure of a portion where a pixel PX is formed in the display device according to the embodiment will now be described with reference to <FIG>.

A buffer layer <NUM> may be disposed on the first substrate <NUM>. The buffer layer <NUM> may prevent the penetration of moisture and oxygen from the outside through the first substrate <NUM>. In addition, the buffer layer <NUM> may planarize the surface of the first substrate <NUM>. In an embodiment, the buffer layer <NUM> may include any one of a silicon nitride (SiNx) film, a silicon oxide (SiO<NUM>) film, and a silicon oxynitride (SiOxNy) film. The buffer layer <NUM> can be omitted depending on the type of the first substrate <NUM> or process conditions.

A semiconductor layer including a semiconductor pattern ACT may be disposed on the buffer layer <NUM>. The semiconductor layer will be described based on the semiconductor pattern ACT. In an embodiment, the semiconductor pattern ACT may be made of one of or a mixture of two or more of polycrystalline silicon, monocrystalline silicon, low temperature polycrystalline silicon, amorphous silicon, and an oxide semiconductor. The semiconductor pattern ACT may include, in an embodiment, a channel region ACTa not doped with an impurity and a source region ACTb and a drain region ACTc doped with an impurity. The source region ACTb is located on a side of the channel region ACTa and is electrically connected to a source electrode SE to be described later. The drain region ACTc is located on the other side of the channel region ACTa and is electrically connected to a drain electrode DE to be described later.

A first insulating layer <NUM> may be disposed on the semiconductor layer including the semiconductor pattern ACT. The first insulating layer <NUM> may be a gate insulating layer in an embodiment. In an embodiment, the first insulating layer <NUM> may be made of any one or a mixture of one or more of inorganic insulating materials such as silicon oxide (SiOx) and silicon nitride (SiNx) and organic insulating materials such as benzocyclobutene (BCB), acrylic materials and polyimide.

A gate conductor including a gate electrode GE may be disposed on the first insulating layer <NUM>. The gate electrode GE may overlap the semiconductor pattern ACT. The gate conductor may include any one or more of aluminum (Al)-based metal including aluminum alloys, silver (Ag)-based metal including silver alloys, copper (Cu)-based metal including copper alloys, molybdenum (Mo)-based metal including molybdenum alloys, chromium (Cr), titanium (Ti), and tantalum (Ta).

A second insulating layer <NUM> may be disposed on the gate conductor including the gate electrode GE. The second insulating layer <NUM> may be made of any one or a mixture of one or more of inorganic insulating materials such as silicon oxide (SiOx) and silicon nitride (SiNx) and organic insulating materials such as benzocyclobutene (BCB), acrylic materials and polyimide.

A data conductor including the source electrode SE and the drain electrode DE may be disposed on the second insulating layer <NUM>. The source electrode SE and the drain electrode DE are disposed on the second insulating layer <NUM> to be spaced apart from each other. The data conductor may include one or more of a metal, an alloy, a metal nitride, a conductive metal oxide, and a transparent conductive material. In an embodiment, the data conductor may have a single film structure or a multi-film structure composed of one or more of nickel (Ni), cobalt (Co), titanium (Ti), silver (Ag), copper (Cu), molybdenum (Mo), aluminum (Al), beryllium (Be), niobium (Nb), gold (Au), iron (Fe), selenium (Se), and tantalum (Ta). In addition, the source electrode SE and the drain electrode DE may be made of an alloy of any one of the above metals and one or more elements selected from titanium (Ti), zirconium (Zr), tungsten (W), tantalum (Ta), niobium (Nb), platinum (Pt), hafnium (Hf), oxygen (O) and nitrogen (N).

The semiconductor pattern ACT, the gate electrode GE, the source electrode SE and the drain electrode DE described above constitute a switching element DT. In <FIG>, the switching element DT is illustrated as a top gate type. However, the switching element DT is not limited to the top gate type. That is, the switching element DT can be formed as a bottom gate type.

A planarization layer <NUM> may be disposed on the data conductor. The planarization layer <NUM> may remove steps, thereby increasing the luminous efficiency of a pixel electrode <NUM> and an organic light emitting layer <NUM> which will be described later. The planarization layer <NUM> may include an organic material in an embodiment. For example, the planarization layer <NUM> may include any one or more of polyimide, polyacryl, and polysiloxane. In an embodiment, the planarization layer <NUM> may include an inorganic material or a composite of an inorganic material and an organic material. A first contact hole CNT1 may be formed in the planarization layer <NUM> to expose at least a part of the drain electrode DE.

The pixel electrode <NUM> may be disposed on the planarization layer <NUM>. The pixel electrode <NUM> may be electrically connected to the drain electrode DE exposed by the first contact hole CNT1. That is, the pixel electrode <NUM> may be an anode which is a hole injection electrode. When formed as an anode, the pixel electrode <NUM> may include a material having a high work function in order to facilitate hole injection. In addition, the pixel electrode <NUM> may be a reflective electrode, a transflective electrode, or a transmissive electrode. The pixel electrode <NUM> may include a reflective material in an embodiment. In an embodiment, the reflective material may include one or more of silver (Ag), magnesium (Mg), chromium (Cr), gold (Au), platinum (Pt), nickel (Ni), copper (Cu), tungsten (W), aluminum (Al), aluminum-lithium (Al-Li), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag).

The pixel electrode <NUM> may be formed as a single film in an embodiment. Alternatively, the pixel electrode <NUM> may be formed as a multi-film in which two or more materials are stacked.

When formed as a multi-film, the pixel electrode <NUM> may include, in an embodiment, a reflective film and a transparent or translucent electrode disposed on the reflective film. In an embodiment, the pixel electrode <NUM> may include a reflective film and a transparent or translucent electrode disposed under the reflective film. For example, the pixel electrode <NUM> may have a three-layer structure of ITO/Ag/ITO.

Here, the transparent or translucent electrode may be made of one or more of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In<NUM>O<NUM>), indium gallium oxide (IGO), and aluminum zinc oxide (AZO).

A pixel defining layer <NUM> may be disposed on the pixel electrode <NUM>. The pixel defining layer <NUM> includes an opening that at least partially exposes the pixel electrode <NUM>. The pixel defining layer <NUM> may include an organic material or an inorganic material. In an embodiment, the pixel defining layer <NUM> may include a material such as photoresist, polyimide resin, acrylic resin, a silicon compound, or polyacrylic resin.

The organic light emitting layer <NUM> may be disposed on the pixel electrode <NUM> and the pixel defining layer <NUM>. More specifically, the organic light emitting layer <NUM> may be disposed on a region of the pixel electrode <NUM> which is exposed through the opening of the pixel defining layer <NUM>. In an embodiment, the organic light emitting layer <NUM> may at least partially cover sidewalls of the pixel defining layer <NUM>.

In an embodiment, the organic light emitting layer <NUM> may emit light of one of red, blue and green colors. In an embodiment, the organic light emitting layer <NUM> may emit white light or emit light of one of cyan, magenta and yellow colors. When the organic light emitting layer <NUM> emits white light, it may include a white light emitting material or may have a stack of a red light emitting layer, a green light emitting layer and a blue light emitting layer.

A common electrode <NUM> may be disposed on the organic light emitting layer <NUM> and the pixel defining layer <NUM>. The common electrode <NUM> may be formed on the entire surface of the organic light emitting layer <NUM> and the pixel defining layer <NUM> in an embodiment. The common electrode <NUM> may be a cathode in an embodiment. In an embodiment, the common electrode <NUM> may include one or more of Li. Ca, Lif/Ca, LiF/Al, Al, Ag, and Mg. In addition, the common electrode <NUM> may be made of a material having a low work function. The common electrode <NUM> may be, in an embodiment, a transparent or translucent electrode including any one or more of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium oxide (In<NUM>O<NUM>), indium gallium oxide (IGO), and aluminum zinc oxide (AZO).

The pixel electrode <NUM>, the organic light emitting layer <NUM> and the common electrode <NUM> described above may constitute an organic light emitting diode OLED. However, the organic light emitting diode OLED is not limited to this configuration and may be a multilayer structure further including a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL).

The second substrate <NUM> may be bonded to the first substrate <NUM> by the cell seal CS. The cell seal CS will be described in detail later.

The second substrate <NUM> may be a transparent insulating substrate in an embodiment. When the second substrate <NUM> is a transparent insulating substrate, the transparent insulating substrate may be a glass substrate, a quartz substrate, a transparent resin substrate, or the like.

Referring to <FIG>, the second substrate <NUM> may include a recessed area RA and a contact area CA.

<FIG> illustrates a back side of the second substrate <NUM>. In an embodiment, the recessed area RA may be an area of the second substrate <NUM> which is recessed in a thickness direction. Here, the thickness direction may be a z-axis direction.

The contact area CA may be defined as an area of the second substrate <NUM> which contacts the first substrate <NUM> or an insulating film disposed on the first substrate <NUM>.

The contact area CA may be an area other than the recessed area RA. While the recessed area RA is an area recessed in the thickness direction, the contact area CA may be a non-recessed area.

In an embodiment, the contact area CA may at least partially surround the recessed area RA. In <FIG>, a case where the contact area CA covers three sides of the recessed area RA is illustrated as an example. The contact area CA and the recessed area RA may be flat surfaces parallel to each other but may be at different levels. In this specification, when two flat surfaces are "at different levels," it means that the two flat surfaces are parallel but different in height. Since the two flat surfaces are different in height, the second substrate <NUM> may include inner sidewalls SW connecting ends of the contact area CA and ends of the recessed area RA (see <FIG>, etc.).

Referring again to <FIG>, the contact area CA may have a "U" shape in an embodiment. In this case, three sides of the recessed area RA may be covered by the contact area CA, but one side of the recessed area RA may be open without being covered by the contact area CA. That is, an opening OP that is not closed by the contact area CA may be formed between the first substrate <NUM> and the second substrate <NUM> in a state where the first substrate <NUM> and the second substrate <NUM> are in contact with each other. The opening OP may be sealed by a frit seal FR, as will be described in detail later.

The second substrate <NUM> may have different thicknesses in the contact area CAand the recessed area RA. In other words, since the contact area CA is an area that is not recessed, the thickness of the second substrate <NUM> may be larger in the contact area CA than in the recessed area RA.

In an embodiment, the recessed area RA may correspond to the display area DA. Specifically, the display area DA may be completely overlapped by the recessed area RA. That is, the recessed area RA may completely accommodate the display area DA. To this end, the planar area of the recessed area RA may be greater than or equal to that of the display area DA.

A bonding area BA may be formed in the contact area CA. The bonding area BA may be an area where a bonding filament BF to be described later is to be formed. In an embodiment, the bonding area BA may be disposed along the contact area CA. That is, the area where the bonding filament BF is formed may completely overlap the contact area CA.

In an embodiment, a width W_C of the contact area CA may be about <NUM> µm to about <NUM> µm. In an embodiment, the bonding area BA may completely overlap the contact area CA. That is, the bonding area BA may be formed inside the contact area CA.

In an embodiment, a width W_B of the bonding area BA may be about <NUM> µm to about <NUM> µm. For stable bonding, the width W_C of the contact area CA may be greater than or equal to the width W_B of the bonding area BA.

The cell seal CS will now be described with reference to <FIG> again. The cell seal CS may bond the first substrate <NUM> and the second substrate <NUM> together. In addition, the cell seal CS may encapsulate the display area DA. That is, when the first substrate <NUM> and the second substrate <NUM> are sealed by the cell seal CS, moisture, oxygen, or foreign matter cannot penetrate into the display area DA.

In an embodiment, the cell seal CS may include the bonding filament BF and the frit seal FR.

In an embodiment, the bonding filament BF at least partially surrounds the display area DA. In an embodiment, the bonding filament BF may be formed over the left non-display area NDA_L, the first corner non-display area NDA_C1, the upper non-display area NDA_U, the second corner non-display area NDA C2, and the right non-display area NDA_R.

In an embodiment, the bonding filament BF is continuously formed to seal three sides of the display area DA. Specifically, the bonding filament BF is interposed between the contact area CA of the second substrate <NUM> and the left non-display area NDA_L, the first corner non-display area NDA_C1, the upper non-display area NDA_U, the second corner non-display area NDA_C2 and the right non-display area NDA_R to bond the first substrate <NUM> and the second substrate <NUM> together.

In an embodiment, the bonding filament BF may consist of a plurality of sub-bonding filaments. That is, referring to <FIG>, the bonding filament BF may include a first sub-bonding filament BF_1 extending in a y-axis direction along the left non-display area NDA_L, a second sub-bonding filament BF_2 extending in the y-axis direction along the right non-display area NDA_R, and a third sub-bonding filament BF_3 extending in an x-axis direction along the upper non-display area NDA_U.

Here, the first sub-bonding filament BF_1 and the third sub-bonding filament BF_3 may extend to the first corner non-display area NDA_C1. In this case, a first intersection point <NUM> where the first sub-bonding filament BF_1 and the third sub-bonding filament BF_3 cross may be formed in the first corner non-display area NDA_C1. In an embodiment, the first sub-bonding filament BF_1 and the third sub-bonding filament BF_3 may extend further in a longitudinal direction beyond the first intersection point <NUM>.

Similarly, the second sub-bonding filament BF_2 and the third sub-bonding filament BF_3 may extend to the second corner non-display areaNDA_C2.

In this case, a second intersection point <NUM> where the second sub-bonding filament BF_2 and the third sub-bonding filament BF_3 cross may be formed in the second corner non-di splay area NDA_C2. In an embodiment, the second sub-bonding filament BF_2 and the third sub-bonding filament BF_3 may extend further in the longitudinal direction beyond the second intersection point <NUM>.

<FIG> is a cross-sectional view taken along line II-II' of <FIG>. Referring to <FIG>, left and right sides of a plurality of organic light emitting diodes OLED disposed on the first substrate <NUM> may be closed by the second substrate <NUM>.

The contact area CA may contact the first substrate <NUM> as illustrated in <FIG>. In the present specification, when "the contact area CA contacts the first substrate <NUM>," it can be understood that the contact area CA directly contacts the first substrate <NUM> or that the contact area CA contacts an insulating film formed on the first substrate <NUM>. This will be described in detail later.

A height H_290 of the second substrate <NUM> may be defined. The height H_290 of the second substrate <NUM> may be defined as a height from a contact surface of the contact area CAto an upper surface of the second substrate <NUM>. In an embodiment, the height H_290 of the second substrate <NUM> may be about <NUM> to about <NUM>.

In addition, a height H_R of the recessed area RA may be defined. The height H_R of the recessed area RA may indicate the degree to which the recessed area RA is recessed from the second substrate <NUM> and indicate a distance from the surface of the contact area CAto a surface of the recessed area RA. In an embodiment, the height H_R of the recessed area RA may be about <NUM> µm to about <NUM> µm.

In an embodiment, the height H_R of the recessed area RA may be greater than or equal to a height of the organic light emitting diodes OLED. Here, "the height of the organic light emitting diodes OLED" may denote a height of a highest portion of an area where the organic light emitting diodes OLED are formed.

Accordingly, the surface of the recessed area RA may be in contact with or spaced apart from the organic light emitting diodes OLED.

Due to this difference in height between the contact area CA and the recess area RA, the inner sidewalls SW connecting the ends of the contact area CA and the recessed area RA may be formed. The inner sidewalls SW may extend in the z-axis direction as illustrated in <FIG>. However, the present invention is not limited to this case, and the inner sidewalls SW may also include at least partially inclined surfaces.

Referring again to <FIG>, the cell seal CS includes the frit seal FR. In an embodiment, the frit seal FR may be disposed in the lower non-display area NDA_D. In addition, both ends of the frit seal FR may extend to the third corner non-display area NDA_C3 and the fourth corner non-display area NDA_C4. That is, the frit seal FR may have a bar shape extending along the longitudinal direction (the x-axis direction in <FIG>) in the lower non-display area NDA_D, the third corner non-display area NDA_C3 and the fourth corner non-display area NDA_C4. In addition, the frit seal FR may be disposed between the driver integrated circuit IC and the display area DA. Accordingly, the first conductive lines <NUM> may at least partially overlap the frit seal FR.

The frit seal FR may include a plurality of frits. In other words, the frit seal FR may be a result of melting a plurality of frits.

The frit seal FR may be disposed between the recessed area RA and the lower non-display area NDA D, the third corner non-display area NDA_C3 and the fourth corner non-display area NDA_C4. That is, the frit seal FR may be disposed between the non-display area NDA and the recessed area RAto bond the first substrate <NUM> and the second substrate <NUM> together.

In an embodiment, a width W_F of the frit seal FR may be about <NUM> µm to about <NUM> µm.

<FIG> is a cross-sectional view taken along line III-III' of <FIG>. <FIG> is a cross-sectional view taken along line IV-IV' of <FIG>. Referring to <FIG> and <FIG>, the opening OP may be formed between the first substrate <NUM> and the second substrate <NUM> at a portion adjacent to the driver integrated circuit IC, as described above. In an embodiment, the opening OP may be completely sealed by the frit seal FR as illustrated in <FIG>.

That is, as illustrated in <FIG>, the opening OP, which is a space defined by the inner sidewalls SW, the recessed area RA and the first substrate <NUM>, is completely filled with the frit seal FR.

When the opening OP is completely sealed by the frit seal FR, the organic light emitting diodes OLED disposed on the first substrate <NUM> may be completely encapsulated by the cell seal CS, that is, the bonding filament BF and the frit seal FR.

The bonding filament BF will now be described in detail with reference to <FIG>.

<FIG> is an enlarged view of a portion 'A' of <FIG>.

Referring to <FIG>, the bonding filament BF may be disposed between the contact area CA and the first substrate <NUM>. The bonding filament BF physically connects the first substrate <NUM> and the second substrate <NUM> in the contact area CA.

In cross-section, the bonding filament BF may extend in the z-axis direction. In addition, the bonding filament BF may extend in the z-axis direction to physically connect the first substrate <NUM> and the contact area CA of the second substrate <NUM>.

In an embodiment, the first substrate <NUM> and/or the second substrate <NUM> may be made of glass.

In this case, the bonding filament BF may be made of the same material as glass that forms the first substrate <NUM> and/or the second substrate <NUM>.

In an embodiment, the width W_B of the bonding filament BF may be about <NUM> µm to about <NUM> µm. The width W_B of the bonding filament BF is significantly smaller than a width of a conventional sealing member (e.g., the frit seal FR) including frit. Therefore, if the frit is replaced with the bonding filament BF, the area of the non-display area NDA can be reduced. As a result, a display device having a narrow bezel can be realized.

In an embodiment, the bonding filament BF may include a central portion C and a peripheral portion P.

The peripheral portion P may surround the central portion C. That is, as illustrated in the cross-section of <FIG>, the peripheral portion P may be disposed on both sides of the central portion C.

The bonding filament BF may be a result of melting and then recrystallizing the contact area CA of the second substrate <NUM> and a part of the first substrate <NUM>. The melting of the contact area CA of the second substrate <NUM> and the part of the first substrate <NUM> may be performed by a femtosecond laser. This will be described in detail later.

In an embodiment, the peripheral portion P and the central portion C may be a result of hardening after melting at different temperatures. Accordingly, the peripheral portion P and the central portion C may have different refractive indices. That is, the peripheral portion P and the central portion C may have different optical characteristics. Thus, the peripheral portion P and the central portion C may be distinguished from each other.

In an embodiment, a width s1 of the central portion C may be about <NUM> µm to about <NUM> µm.

The bonding filament BF directly and physically connects the first substrate <NUM> and the second substrate <NUM>. Since the bonding filament BF is formed by melting a part of the first substrate <NUM> and a part of the second substrate <NUM>, it may include the materials of the first substrate <NUM> and the second substrate <NUM>. That is, the bonding filament BF may include a material in which the materials of the first substrate <NUM> and the second substrate <NUM> are mixed without any boundary or may include a recrystallized mixture of the materials of the first substrate <NUM> and the second substrate <NUM>.

In an embodiment, the contact area CA of the second substrate <NUM> may contact an insulating film disposed on the first substrate <NUM>. One or more insulating films may be disposed on the first substrate <NUM>. In an embodiment, the insulating films may include a first insulating film ILD1, a second insulating film ILD2, and a third insulating film ILD3 stacked sequentially. Although three insulating films are stacked on the first substrate <NUM> in <FIG>, this is merely an example, and the number of insulating films is not limited to three. That is, in an embodiment, the number of insulating films may be less than three or may be four or more. In an embodiment, the first insulating film ILD1 may be made of the same material as the buffer layer <NUM> of the display area DA. That is, the first insulating film ILD1 and the buffer layer <NUM> may be formed simultaneously in the same process. However, this is merely an example, and the method of forming the first insulating film ILD1 and the buffer layer <NUM> is not limited to this example.

In an embodiment, the second insulating film ILD2 may be made of the same material as the first insulating layer <NUM> of the display area DA. That is, the second insulating film ILD2 and the first insulating layer <NUM> may be formed simultaneously in the same process.

In an embodiment, the third insulating film ILD3 may be made of the same material as the second insulating layer <NUM> of the display area DA. That is, the third insulating film ILD3 and the second insulating layer <NUM> may be formed simultaneously in the same process.

In an embodiment, the bonding filament BF may grow from the first substrate <NUM> to pass through a plurality of insulating films. That is, the bonding filament BF may pass through the first insulating film ILD1, the second insulating film ILD2 and the third insulating film ILD3.

In an embodiment, the bonding filament BF may grow from the second substrate <NUM> to pass through a plurality of insulating films.

In this case, side surfaces of the bonding filament BF may contact at least one of the insulating films.

In addition, a region of the contact area CA excluding the region where the bonding filament BF is formed may contact the first substrate <NUM> or may contact the insulating films formed on the first substrate <NUM>.

<FIG> is a graph illustrating the effect of the present invention.

<FIG> illustrates strength and bonding width when two sheets of glass are bonded by first laser bonding LB1, second laser bonding LB2, third laser bonding LB3, fourth laser bonding LB4, and frit bonding FB.

In the first laser bonding LB1, the second laser bonding LB2, the third laser bonding LB3 and the fourth laser bonding LB4, two sheets of glass are bonded by forming a bonding filament between the two sheets of glass. The first laser bonding LB1, the second laser bonding LB2, the third laser bonding LB3 and the fourth laser bonding LB4 are different only in the type of the two sheets of glass and are the same in that the bonding filament is formed using a femtosecond laser.

Referring to <FIG>, laser bonding that forms a bonding filament has a bonding width of <NUM>/<NUM>th of the conventional frit bonding FB and a bonding strength similar or superior to the conventional frit bonding FB. That is, when two sheets of glass are bonded by forming a bonding filament, it is possible to increase the bonding strength while reducing the area required for bonding (which affects the area of the non-display area NDA of the display device). Accordingly, a display device having a narrow bezel and excellent bonding strength can be realized.

Hereinafter, display devices according to other embodiments will be described. In the following embodiments, the same elements as those already described above will be indicated by the same reference numerals, and a redundant description of the same elements will be omitted or given briefly.

<FIG> is a partial plan view of a display device according to an embodiment. <FIG> is a cross-sectional view taken along line V-V' of <FIG>.

Referring to <FIG>, a middle area MA may be further defined between a recessed area RA and a contact area CA of a second substrate <NUM> in an embodiment.

As described above, the recessed area RA and the contact area CA may be flat surfaces, but may be at different levels.

The middle area MA may be disposed between the recessed area RA and the contact area CA and may include at least partially inclined surfaces. That is, as illustrated in <FIG>, the middle area MA may include inclined surfaces extending downward from inner sidewalls SW of the contact area CAto ends of the recessed area RA. Accordingly, a thickness of the second substrate <NUM> may gradually decrease from the contact area CA toward the recessed area RA.

In an embodiment, the recessed area RA may be obtained by partially etching the second substrate <NUM>. In the etching process, a boundary between the recessed area RA and the contact area CA may be formed as a line as illustrated in <FIG> or may be formed as a plane as illustrated in <FIG>. The boundary may be especially noticeable when the recessed area RA is formed by a chemical etching method. This is because the chemical etching method requires a certain margin in the etching process, and the middle area MA having an intermediate value of two levels is needed in order to form two planes having different levels (the contact area CA and the recessed area RA).

In an embodiment in which the contact area CA has a "U" shape in plan view, the middle area MA may also have a "U" shape along the contact area CA. In addition, the middle area MA may be a buffer area formed in the etching process and may have rounded corners.

Since the recessed area RA needs to cover a display area DA completely, it may basically have a quadrilateral shape. However, due to the presence of the middle area MA, corners of the recessed area RA may be rounded along the middle area MA in an embodiment.

In an embodiment, a width W_M of the middle area MA (defined as a distance between ends of the contact area CA and the ends of the recessed area RA) may be about <NUM> µm to about <NUM> µm.

Since the middle area MA has a thickness different from that of the recessed area RA, the middle area MA and the recessed area RA may have different refractive indices. In an embodiment, the refractive index of the middle area MA may be greater than that of the recessed area RA. Thus, the middle area MA can be distinguished from the recessed area RA.

<FIG> is a partial cross-sectional view of a display device according to an embodiment.

<FIG> is a modified example of <FIG>. As described above, a contact area CA may directly contact a first substrate <NUM>. Specifically, a region of the contact area CA excluding a region where a bonding filament BF is formed may directly contact the first substrate <NUM>.

This structure may result from the process of partially removing an insulating film disposed on the first substrate <NUM> and then bringing a second substrate <NUM> into contact with the first substrate <NUM>. That is, this structure can be obtained by completely removing an insulating film near ends of the first substrate <NUM> and then forming the bonding filament BF in a state where the contact area CA of the second substrate <NUM> is in direct contact with the first substrate <NUM>. However, this is merely an example, and this structure is not necessarily obtained by the above process.

In an embodiment, inner sidewalls SW of the second substrate <NUM> may contact one or more of a first insulating film ILD1, a second insulating film ILD2 and a third insulating film ILD3.

In <FIG>, the inner sidewalls SW of the second substrate <NUM> contact the first insulating film ILD1, the second insulating film ILD2, and the third insulating film ILD3. However, the present invention is not limited to this case. In an embodiment, the first insulating film ILD1, the second insulating film ILD2, and the third insulating film ILD3 may be spaced apart from the inner sidewalls SW.

When the region of the contact area CA excluding the region where the bonding filament BF is formed directly contacts the first substrate <NUM>, the bonding performance of the first substrate <NUM> and the second substrate <NUM> can be improved. That is, if an insulating film is interposed between the contact area CA and the first substrate <NUM>, it may increase a physical distance between the contact area CA and the first substrate <NUM>, thereby deteriorating the bonding performance. However, this can be prevented in the embodiment of <FIG>.

<FIG> is a layout view of a display device according to an embodiment. <FIG> is a partial plan view of the embodiment of <FIG>. <FIG> is a cross-sectional view taken along line VI-VI' of <FIG>. <FIG> is a cross-sectional view taken along line VII-VII' of <FIG>.

Referring to <FIG>, two driver integrated circuits IC may be disposed on a first substrate <NUM> in an embodiment. For ease of description, a driver integrated circuit disposed in a lower non-display area NDA_D will be referred to as a first driver integrated circuit IC1, and a driver integrated circuit disposed in an upper non-display area NDA_U will be referred to as a second driver integrated circuit IC2.

The first driver integrated circuit IC1 is substantially the same as the driver integrated circuit IC described above with reference to <FIG>, etc., and thus a detailed description thereof is omitted.

As the number of images formed in a display area DA increases, it may be difficult to drive the display area DA using only one driver integrated circuit. In this case, an additional driver integrated circuit may be further disposed.

In an embodiment, the second driver integrated circuit IC2 may be placed to face the first driver integrated circuit IC1. That is, the display area DA may be disposed between the second driver integrated circuit IC2 and the first driver integrated circuit IC1.

The second driver integrated circuit IC2 may generate signals necessary for driving the display area DA and transmit the generated signals to the display area DA. To this end, a plurality of second conductive lines <NUM> may be disposed between the second driver integrated circuit IC2 and the display area DA. The second conductive lines <NUM> may be disposed between the second driver integrated circuit IC2 and the display area DA to transmit signals generated by the second driver integrated circuit IC2 to the display area DA.

In an embodiment, a frit seal FR may include a first sub-frit seal FR_1 and a second sub-frit seal FR_2.

Each of the first sub-frit seal FR_1 and the second sub-frit seal FR_2 may have a bar shape extending in a longitudinal direction. In an embodiment, the longitudinal direction may be an x-axis direction of <FIG>. Therefore, the first sub-frit seal FR_1 and the second sub-frit seal FR_2 may extend parallel to each other.

In an embodiment, the first sub-frit seal FR_1 may be disposed in the lower non-display area NDA_D. Specifically, the first sub-frit seal FR_1 may be disposed between the display area DA and the first driver integrated circuit IC1. Accordingly, the first sub-frit seal FR_1 may at least partially overlap a plurality of first conductive lines <NUM>.

In an embodiment, the second sub-frit seal FR_2 may be disposed in the upper non-display area NDA_U. Specifically, the second sub-frit seal FR_2 may be disposed between the display area DA and the second driver integrated circuit IC2. Accordingly, the second sub-frit seal FR_2 may at least partially overlap the second conductive lines <NUM>.

In an embodiment, a bonding filament BF may include a first sub-bonding filament BF_1 and a second sub-bonding filament BF_2.

Each of the first sub-bonding filament BF_1 and the second sub-bonding filament BF_1 may have a bar shape extending in the longitudinal direction. In an embodiment, the longitudinal direction may be a y-axis direction of <FIG>.

In an embodiment, the first sub-bonding filament BF_1 may be disposed in a left non-display area NDA_L. Alternatively, both ends of the first sub-bonding filament BF_1 may extend to a first corner non-display area NDA_C1 or a fourth corner non-display areaNDA_C4.

In an embodiment, the second sub-bonding filament BF_2 may be disposed in a right non-display area NDA_R. Alternatively, both ends of the second sub-bonding filament BF_2 may extend to a second corner non-display area NDA_C2 or a third corner non-display area NDA_C3.

The first sub-bonding filament BF_1 and the second sub-bonding filament BF_2 may be disposed between a contact area CA and the first substrate <NUM>.

In an embodiment, the contact area CA of a second substrate <NUM> may include a first sub-contact area CA_1 and a second sub-contact area CA_2.

The contact area CA will now be described with reference to <FIG>.

Each of the first sub-contact area CA_1 and the second sub-contact area CA_2 may have a bar shape extending in the longitudinal direction. In an embodiment, the longitudinal direction may be the y-axis direction of <FIG> and <FIG>.

The first sub-contact area CA_1 and the second sub-contact area CA_2 may extend parallel to each other, but may be spaced apart from each other by a predetermined distance.

A recessed area RA may be disposed between the first sub-contact area CA_1 and the second sub-contact area CA_2. Although not illustrated in <FIG>, a middle area may be disposed between the first sub-contact area CA_1 and the recessed area RA and/or between the second sub-contact area CA_2 and the recessed area RA, as described above with reference to <FIG>.

The first sub-contact area CA_1 and the second sub-contact area CA_2 may contact the first substrate <NUM>. The first sub-bonding filament BF_1 may be disposed between the first sub-contact area CA_1 and the first substrate <NUM>, and the second sub-bonding filament BF_2 may be disposed between the second sub-contact area CA_1 and the first substrate <NUM>.

That is, the display area DA may be encapsulated by the first sub-bonding filament BF_1, the second sub-bonding filament BF_2, the first sub-frit seal FR_1 and the second sub-frit seal FR_2 arranged to surround the display area DA.

Referring to <FIG>, upper and lower sides of the display area DA may be encapsulated by the first sub-frit seal FR_1 and the second sub-frit seal FR_2. When the first sub-contact area CA_1 and the second sub-contact area CA_2 are arranged side by side in the form of "<NUM>" as described above with reference to <FIG>, a first opening OP1 and a second opening OP2 may be formed between both ends of the recessed area RA and the first substrate <NUM>. The first opening OP1 may be disposed adjacent to the first driver integrated circuit IC1, and the second opening OP2 may be disposed adjacent to the second driver integrated circuit IC2.

The first sub-frit seal FR_1 and the second sub-frit seal FR_2 may seal the first opening OP1 and the second opening OP2. Specifically, the first sub-frit seal FR_1 may seal the first opening OP1, and the second sub-frit seal FR_2 may seal the second opening OP2. Accordingly, the upper and lower sides of the display area DA may be sealed by the first sub-frit seal FR_1 and the second sub-frit seal FR_2.

Referring to <FIG>, left and right sides of the display area DA may be sealed by the first sub-bonding filament BF_1 and the second sub-bonding filament BF_2.

That is, both ends of the second substrate <NUM> may be bent, and the first sub-contact area CA_1 and the second sub-contact area CA_2, which are the bent ends of the second substrate <NUM>, may contact the first substrate <NUM>.

The first sub-bonding filament BF_1 may be disposed between the first sub-contact area CA_1 and the first substrate <NUM>, and the second sub-bonding filament BF_2 may be disposed between the second sub-contact area CA_2 and the first substrate <NUM>.

The cross-sectional structures of the first sub-bonding filament BF_1 and the second sub-bonding filament BF_2 may be substantially the same as that described above with reference to <FIG>.

That is, each of the first sub-bonding filament BF_1 and the second sub-bonding filament BF_2 may include a central portion C and a peripheral portion P and contain both the material of the first substrate <NUM> and the material of the second substrate <NUM>. That is, each of the first sub-bonding filament BF_1 and the second sub-bonding filament BF_2 may include a mixture of the materials of the first substrate <NUM> and the second substrate <NUM> or a recrystallized mixture of the materials of the first substrate <NUM> and the second substrate <NUM>.

The first sub-bonding filament BF_1, the second sub-bonding filament BF_2, the first sub-frit seal FR_1 and the second sub-frit seal FR_2 may constitute a cell seal CS as described above. The cell seal CS may surround the display area DA and encapsulate the display area DA. Accordingly, the introduction of moisture, oxygen, or foreign matter into the display area DA can be prevented.

<FIG> is a partial cross-sectional view of a display device according to an embodiment. Referring to <FIG>, in an embodiment, a bonding filament may include at least two sub-bonding filaments extending parallel to each other.

For ease of description, in <FIG>, a bonding filament disposed on an inner side will be referred to as an inner bonding filament BF_I, and a bonding filament disposed outside the inner bonding filament BF_I will be referred to as an outer bonding filament BF O.

In an embodiment, the inner bonding filament BF_I may be disposed closer to a recessed area RA than the outer bonding filament BF_O. That is, the outer bonding filament BF_O may surround the inner bonding filament BF_I.

In an embodiment, the inner bonding filament BF_I and the outer bonding filament BF_O may be spaced apart from each other. The inner bonding filament BF_I and the outer bonding filament BF_O spaced apart from each other may extend in the same direction.

That is, when the inner bonding filament BF_I extends along an x-axis or a y-axis, the outer bonding filament BF_O may extend along the inner bonding filament BF_I in a x-axis or y-axis direction (in top view).

In an embodiment, the inner bonding filament BF_I may include a central portion C_I and a peripheral portion P_I disposed outside the central portion C_I. The central portion C_I and the peripheral portion P_I may be the same as those of the bonding filaments BF described above in the display devices according to the embodiments.

The outer bonding filament BF_O may also include a central portion C_O and a peripheral portion P_O. The central portion C_O and the peripheral portion P_O may be the same as those of the bonding filaments BF described above in the display devices according to the embodiments.

That is, when the inner bonding filament BF_I and the outer bonding filament BF_O are spaced apart from each other, the two central portions C_I and C_O may be visible between a contact area CA and a first substrate <NUM>.

When a plurality of bonding filaments are formed between the contact area CAand the first substrate <NUM> as described above, the first substrate <NUM> and a second substrate <NUM> can be more stably bonded together. That is, the bonding strength between the first substrate <NUM> and the second substrate <NUM> can be increased.

In an embodiment, the inner bonding filament BF_I and the outer bonding filament BF_O may at least partially overlap each other. That is, the peripheral portion P_I of the inner bonding filament BF_I and the peripheral portion P_O of the outer bonding filament BF_O may at least partially overlap each other. Even in this case, the central portion C_I of the inner bonding filament BF_I and the central portion C_O of the outer bonding filament BF_O may be spaced apart from each other and may be visible in cross-section.

In an embodiment, the inner bonding filament BF_I and the outer bonding filament BF_O may be closer to each other. In this case, the central portion C_I of the inner bonding filament BF_I and the central portion C_O of the outer bonding filament BF_O may partially overlap each other. When the central portion C_I of the inner bonding filament BF_I and the central portion C_O of the outer bonding filament BF_O partially overlap each other, only one central portion may be visible in cross-section.

<FIG> is a partial cross-sectional view of a display device according to an embodiment. Referring to <FIG>, in an embodiment, a part of a bonding filament BF3 may connect a recessed area RA and a surface of a first substrate <NUM>.

As will be described in detail later, the bonding filament BF3 may be formed by irradiating a femtosecond laser beam while focusing the femtosecond laser beam on a contact area CA of a second substrate <NUM> or the first substrate <NUM>. The bonding filament BF3 may grow between interfaces that are in contact with each other or may connect surfaces that are spaced apart by a predetermined distance.

That is, a part of the bonding filament BF3 may connect the contact area CA and the first substrate <NUM>, and the remaining part of the bonding filament BF3 may connect the recessed area RA adjacent to the contact area CA and the first substrate <NUM>.

In <FIG>, a peripheral portion P3 disposed outside a central portion C3 includes a first sub-peripheral portion PC and a second sub-peripheral portion PR.

In an embodiment, the first sub-peripheral portion PC may connect the contact area CAand the first substrate <NUM>, and the second sub-peripheral portion PR may connect the recessed area RA and the first substrate <NUM>.

In this case, a height H_P of the second sub-peripheral portion PR may be greater than or equal to a distance between a surface of the recessed area RA and a surface of the first substrate <NUM>.

While a case where the peripheral portion P3 connects the first substrate <NUM> and the recessed area RA is illustrated in <FIG>, the present invention is not limited to this case. In an embodiment, at least a part of the central portion C3 may connect the first substrate <NUM> and the recessed area RA.

In <FIG> and <FIG>, no insulating film is illustrated for ease of description. However, the cases of <FIG> and <FIG> may also include an insulating film structure as described above with reference to <FIG> and <FIG>.

Hereinafter, methods of manufacturing a display device according to embodiments will be described.

Some of the elements described below may be substantially the same as those of the display devices according to the above-described embodiments, and thus a description thereof will be omitted in order to avoid redundancy.

<FIG> is a layout view for explaining a method of manufacturing a display device according to an embodiment. <FIG> is a partial plan view of a display device according to an embodiment. <FIG> is a layout view for explaining the method of manufacturing a display device according to the embodiment. <FIG> is a cross-sectional view taken along line VIII-VIII' of <FIG>.

Referring to <FIG>, the method of manufacturing a display device according to the embodiment includes preparing a first substrate <NUM> in which a display area DA and a non-display area NDA disposed outside the display area DA are defined and a second substrate <NUM> which faces the first substrate <NUM>; applying a frit F1 onto the first substrate <NUM> or the second substrate <NUM> to overlap the non-display area NDA of the first substrate <NUM>; forming a recessed area RA and a contact area CA by recessing a part of the second substrate <NUM> in a thickness direction; forming a bonding filament BF for connecting the contact area CA and the first substrate <NUM> by irradiating a laser beam in a state where the contact area CA and the first substrate <NUM> are in contact with each other; and forming a frit seal FR by curing the frit F1.

<FIG> illustrates the first substrate <NUM>. The first substrate <NUM> may be substantially the same as those of the display devices according to the above-described embodiments. That is, a plurality of pixels, each including an organic light emitting diode OLED, may be disposed in the display area DA, and the non-display area NDA may be divided into an upper non-display area NDA_U, a lower non-display area NDA_D, a left non-display area NDA_L, a right non-display area NDA_R, and first through fourth corner non-display areas NDA_C1 through NDA_C4.

The second substrate <NUM> may face the first substrate <NUM>. The second substrate <NUM> may be substantially the same as those of the display devices according to the above-described embodiments.

Next, the frit F1 may be applied onto the first substrate <NUM> or the second substrate <NUM> to overlap the non-display area NDA of the first substrate <NUM>.

In an embodiment, the frit F1 may be applied onto the first substrate <NUM> or the second substrate <NUM>. As illustrated in <FIG>, which shows an embodiment not according to the claimed invention, the applied frit F1 may be disposed in the lower non-display area NDA_D in a state where the first substrate <NUM> and the second substrate <NUM> are stacked on each other. That is, the frit F1 may be applied to be disposed between a driver integrated circuit IC and the display area DA and to at least partially overlap a plurality of first conductive lines <NUM>. The frit F <NUM> may be in the form of a dough containing glass powder. The frit F1 may later be cured into the frit seal FR.

In an embodiment, the applied frit F1 may be placed to overlap the lower non-display area NDA_D in a state where the first substrate <NUM> and the second substrate <NUM> are stacked on each other. In addition, both ends of the frit F1 may extend to the third corner non-display area NDA_C3 and/or the fourth corner non-display area NDA_C4.

Alternatively, when a display device includes two driver integrated circuits as illustrated in <FIG>, the frit F1 may also be placed in the upper non-display area NDA_U.

Next, referring to <FIG>, a part of the second substrate <NUM> may be recessed in the thickness direction to form the recessed area RA and the contact area CA. In an embodiment, a part of the second substrate <NUM> may be recessed by a wet etching method. In an embodiment, a part of the second substrate <NUM> may be recessed by a drying etching method or cut mechanically to form the recessed area RA.

The contact area CA may be disposed outside the recessed area RA. That is, the contact area CA may be defined as a non-recessed area.

The contact area CA may cover three sides of the recessed area RA as illustrated in <FIG> or may be disposed in the form of "<NUM>" with the recessed area RA interposed between parts of the contact area CA as illustrated in <FIG>.

In addition, at this stage, a middle area MA may be formed between the contact area CA and the recessed area RA as illustrated in <FIG>.

Next, referring to <FIG> and <FIG>, which shows an embodiment not according to the claimed invention, the bonding filament BF for connecting the contact area CA and the first substrate <NUM> may be formed by irradiating a laser beam in a state where the contact area CA and the first substrate <NUM> are in contact with each other.

The second substrate <NUM> may be placed to face the first substrate <NUM>. Accordingly, the display area DA may be completely overlapped by the recessed area RA of the second substrate <NUM>.

The contact area CA may contact the non-display region NDA of the first substrate <NUM>.

That is, the contact area CA may directly contact the first substrate <NUM> or may contact an insulating film formed on the first substrate <NUM>.

In an embodiment, the bonding filament BF may be formed between the first substrate <NUM> and the contact area CA by irradiating a laser beam.

In an embodiment, the laser beam may be a femtosecond laser beam. In the present specification, the femtosecond laser beam may denote a laser beam having a pulse width of about <NUM> femtoseconds to about <NUM> femtoseconds.

In an embodiment, a laser beam L1 may be irradiated continuously. That is, the laser beam L1 may be continuously irradiated along the contact area CA as illustrated in <FIG> (showing an embodiment not according to the claimed invention) In an embodiment in which the contact area CA is formed over the left non-display area NDA_L, the upper non-display area NDA_U and the right non-display area NDA_R (in top view), the laser beam L1 may be irradiated along the left non-display area NDA_L, the upper non-display area NDA_U, and the right non-display area NDA_R (see ① in <FIG>).

Referring to <FIG>, the laser beam L1 may be irradiated from above the second substrate <NUM> toward the first substrate <NUM>. In an embodiment, a focus FO1 of the laser beam L1 may be set inside the first substrate <NUM>.

For ease of description, references of the depth of focus will be set. An upper surface of the first substrate <NUM> may be defined as a point where the depth of focus is "zero. " In addition, the depth of focus at a point inside the first substrate <NUM> which is at a distance z from the upper surface of the first substrate <NUM> may be defined as -z.

In an embodiment, the depth of focus of the laser beam L1 may be about -<NUM> µm to less than about <NUM> µm. When the laser beam L1 is irradiated, high energy may be provided around the focus FO1. The provided energy may turn a part of the first substrate <NUM> and a part of the contact area CA of the second substrate <NUM> into a plasma state. In other words, the part of the first substrate <NUM> and a part of the contact area CA of the second substrate <NUM> are plasmarized by the provided energy. The part of the first substrate <NUM> and the part of the second substrate <NUM> in the plasma state may be melted and recrystallized in a state where they are mixed with each other. In this process, a central portion C of the bonding filament BF may be formed (see <FIG>).

Heat may be generated around the central portion C in the plasma state and may melt a portion around the central portion C. Accordingly, a peripheral portion P of the bonding filament BF may be formed to surround the central portion C. The central portion C and the peripheral portion P may grow around the focus FO1 in a z-axis direction. The peripheral portion P and the central portion C of the bonding filament BF may connect the first substrate <NUM> and the second substrate <NUM>.

In <FIG>, the contact area CAand the first substrate <NUM> are in contact with each other. However, the present invention is not limited to this case. In an embodiment, the bonding filament BF may grow in the z-axis direction to connect the first substrate <NUM> and the contact area CA even when the contact area CA and the first substrate <NUM> are spaced apart from each other by a predetermined distance (by an insulating film). In addition, the bonding filament BF3 may connect the recessed area RA and the first substrate <NUM> by overcoming a gap between a part of the recessed area RA and the first substrate <NUM> as in the embodiment of <FIG>, which shows an embodiment not according to the claimed invention.

Since melting temperatures of the peripheral portion P and the central portion C are different, optical characteristics of the peripheral portion P and the central portion may be different. For example, refractive indices of the peripheral portion P and the central portion C may be different from each other. Therefore, the peripheral portion P and the central portion C can be distinguished from each other.

Next, the frit seal FR may be formed by curing the frit F1. The curing of the frit F1 may be achieved by general laser irradiation or infrared irradiation, not femtosecond laser irradiation.

When a laser beam is irradiated to the frit F1, the frit F1 may be at least partially melted to form the frit seal FR having bonding performance. The disposition of the frit seal FR may be substantially the same as those in the display devices according to the above-described embodiments, and thus a detailed description thereof is omitted.

A process temperature for forming a bonding filament is relatively high compared to a process temperature for forming a frit seal. That is, when a filament is formed in a portion where conductive lines are disposed, the conductive lines can be damaged by high temperature. Thus, by using the frit seal in the portion overlapping the conductive lines and using the bonding filament in the remaining portion, it is possible to realize a narrow bezel and prevent the damage to the conductive lines due to heat.

While a case where the bonding filament BF is formed before the frit seal FR has been described for ease of description, the present invention is not limited to this order. That is, in an embodiment, the frit seal FR may be formed before the bonding filament BF.

The method of manufacturing a display device according to the embodiment may include partially removing an insulating film formed on the first substrate <NUM> before bringing the contact area CA and the first substrate <NUM> into contact with each other (see <FIG>).

As described above with reference to <FIG> and <FIG>, one or more insulating films may be disposed on the first substrate <NUM>. In an embodiment, the insulating films disposed on the first substrate <NUM> may be partially removed to expose the first substrate <NUM>. The contact area CA may contact an area of the substrate <NUM> exposed by the removing of the insulating films. That is, when the insulating films are removed, the first substrate <NUM> may directly contact the contact area CA.

In an embodiment, the removing of the insulating films may be omitted. In this case, the bonding filament BF may pass through the insulating films as illustrated in <FIG>.

A method of manufacturing a display device according to an embodiment will now be described.

<FIG> is a layout view for explaining a method of manufacturing a display device according to an embodiment.

Referring to <FIG>, a bonding filament BF for connecting a contact area CA and a first substrate <NUM> may be formed by irradiating a laser beam in a state where the contact area CA and the first substrate <NUM> are in contact with each other. In this operation, the laser beam may be irradiated intermittently.

Specifically, a first sub-bonding filament BF_1 and a second sub-bonding filament BF_2 may be formed by irradiating a laser beam in a y-axis direction. In an embodiment, the first sub-bonding filament BF_1 may be formed between the contact area CA and a left non-display area NDA_L, and the second sub-bonding filament BF_2 may be formed between the contact area CA and a right non-display area NDA_R (see ② and ③ in <FIG>).

In an embodiment in which the contact area CA includes a first sub-contact area CA_1 and a second sub-contact area CA_2 as illustrated in <FIG>, a laser beam may also be irradiated in the y-axis direction to form the first sub-bonding filament BF_1 and the second sub-bonding filament BF_2.

Then, a third sub-filament BF_3 may be formed by irradiating a laser beam in an x-axis direction.

The third sub-bonding filament BF_3 may be formed over an upper non-display area NDA_U.

In an embodiment, the third sub-bonding filament BF_3 may intersect the first sub-bonding filament BF_1 and the second sub-bonding filament BF_2.

The forming of the third sub-bonding filament BF_3 may be omitted in the embodiment in which the contact area CA includes the first sub-contact area CA_1 and the second sub-contact area CA_2 as illustrated in <FIG>.

Accordingly, a first intersection point <NUM> may be formed in a first corner non-display area NDA_C1, and a second intersection point <NUM> may be formed in a second corner non-display area NDA_C2.

<FIG> is a cross-sectional view for explaining a method of manufacturing a display device according to an embodiment.

Referring to <FIG>, unlike <FIG>, a laser beam L2 may be irradiated from under a first substrate <NUM>. The laser beam L2 may be irradiated from under the first substrate <NUM> toward a second substrate <NUM>. In an embodiment, a focus FO2 of the laser beam L2 may be set inside the second substrate <NUM>.

For ease of description, references of the depth of focus will be set. A surface of a contact area CA of the second substrate <NUM> may be defined as a point where the depth of focus is "zero. " In addition, the depth of focus at a point inside the second substrate <NUM> which is at a distance z from the surface of the contact area CA may be defined as +z.

In an embodiment, the depth of focus of the laser beam L2 may be about <NUM> µm to less than about <NUM> µm. When the laser beam L2 is irradiated, high energy may be provided around the focus FO2. The provided energy may turn a part of the first substrate <NUM> and a part of the contact area CA of the second substrate <NUM> into a plasma state. The part of the first substrate <NUM> and the part of the second substrate <NUM> in the plasma state may be melted and recrystallized in a state where they are mixed with each other. In this process, a central portion C of a bonding filament BF may be formed (see <FIG>).

According to embodiments, the area occupied by a cell seal can be reduced. Therefore, a display device having a narrow bezel can be realized.

Claim 1:
A display device comprising:
a first substrate (<NUM>) in which a display area (DA) and a non-display area (NDA) disposed outside the display area (DA) are defined, the first substrate (<NUM>) consisting of four lateral sides;
a second substrate (<NUM>, <NUM>) which faces the first substrate (<NUM>) and comprises an area (RA) recessed in a thickness direction and a contact area (CA) disposed outside the recessed area (RA); and
a cell seal (CS) which bonds the first substrate (<NUM>) and the second substrate (<NUM>, <NUM>) together,
wherein the cell seal (CS) comprises a bonding filament (BF) and a frit seal (FR), the bonding filament (BF) is disposed along two opposing sides or three sides of the first substrate (<NUM>) between the contact area (CA) and the non-display area (NDA) to connect the contact area (CA) and the first substrate (<NUM>), the frit seal (FR) is disposed along a remaining one or two sides of the first substrate (<NUM>) between the recessed area (RA) and the non-display area (NDA), wherein the bonding filament (BF) and the frit seal (FR) are laterally spaced apart from each other.