Display apparatus

A display apparatus including: a lower substrate bent around a first bending axis that extends in a first direction; an upper substrate opposing the lower substrate and having a first surface facing the lower substrate; a pixel electrode disposed on the lower substrate; a color filter disposed on the lower substrate so as to correspond to the pixel electrode; and a first column spacer disposed on the first surface so as to correspond to at least a portion of the color filter and extending in a second direction that intersects the first direction.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 10-2016-0131618, filed on Oct. 11, 2016, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

Field

Exemplary embodiments relate to a display apparatus. More particularly, exemplary embodiments relate to a display apparatus that may be manufactured by a simplified process having a reduced defect rate.

Discussion of the Background

As various electronic devices, such as mobile phones, personal digital assistants (PDAs), computers, and large TVs, have been developed, the demand for display apparatuses applicable to such electronic devices has increased. Among display apparatuses, liquid crystal display (LCD) apparatuses have advantages in terms of low power consumption, easy display of moving images, and a high contrast ratio.

LCD apparatuses include a liquid crystal layer between an upper substrate and a lower substrate and generate a transmittance difference by changing an orientation of liquid crystal molecules by applying an electric field to the liquid crystal layer. LCD apparatuses have been implemented as any of various apparatuses, such as flat-panel display apparatuses, curved display apparatuses, or flexible display apparatuses, in accordance with recent trends in technology.

A conventional LCD display apparatus has a problem in that an additional process is required to align an upper substrate and a lower substrate in a process of adhering the upper substrate and the lower substrate.

SUMMARY

Exemplary embodiments provide a display apparatus that may simplify a process and may minimize a defect rate in a manufacturing process.

An exemplary embodiment discloses a display apparatus, including: a lower substrate bent around a first bending axis that extends in a first direction; an upper substrate opposing the lower substrate and having a first surface facing the lower substrate; a pixel electrode disposed on the lower substrate; a color filter disposed on the lower substrate so as to correspond to the pixel electrode; and a first column spacer disposed on the first surface so as to correspond to at least a portion of the color filter and extending in a second direction that intersects the first direction

The first direction and the second direction may be perpendicular to each other.

The upper substrate may be bent around a second bending axis extending in a third direction that intersects the second direction.

The third direction may be parallel to the first direction.

The lower substrate may be bent according to a first curvature, and the upper substrate may be bent according to a second curvature different from the first curvature.

The first curvature of the lower substrate may be greater than the second curvature of the upper substrate.

The pixel electrode may extend in the first direction.

The color filter may include at least one from among a red color filter, a blue color filter, a green color filter, and a white color filter.

The color filter may not overlap at least a portion of the first column spacer.

The first column spacer may include a first portion that overlaps the color filter and second portions that do not overlap the color filter

The first portion may be located at a center of the first column spacer.

The second portions may be located at two sides of the first portion.

The display apparatus may further include an organic film disposed between the color filter and the first column spacer.

The first portion of the first column spacer may contact the organic film.

The display apparatus may further include a second column spacer disposed farther from a central axis of the upper substrate that is parallel to the second bending axis than the first column spacer, wherein a second length of the second column spacer in the second direction is greater than a first length of the first column spacer in the second direction.

The display apparatus may further include a second column spacer located farther from a central axis of the upper substrate than the first column spacer, the central axis of the upper substrate being parallel to the second bending axis, wherein a second height of the second column spacer is greater than a first height of the first column spacer.

An exemplary embodiment also discloses a display apparatus including: a lower substrate bent around a first bending axis that extends in a first direction; an upper substrate opposing the lower substrate and having a first surface facing the lower substrate; a column spacer disposed on the first surface of the upper substrate and including a first portion and a second portion that contacts the first portion; and a color filter located on the lower substrate so that the first portion overlaps the column spacer.

The lower substrate may be bent around a first bending axis that extends in a first direction.

The column spacer may extend in a second direction that intersects the first direction.

A thickness of the first portion may be greater than a thickness of the second portion.

The display apparatus may further include an organic film disposed between the color filter and the column spacer, wherein the first portion contacts the organic film.

The present disclosure may be embodied within a system, a method, a computer program, or any combination thereof.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Various exemplary embodiments are described herein with reference to sectional illustrations that are schematic illustrations of idealized exemplary embodiments and/or intermediate structures. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments disclosed herein should not be construed as limited to the particular illustrated shapes of regions, but are to include deviations in shapes that result from, for instance, manufacturing. The regions illustrated in the drawings are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to be limiting.

FIG. 1is a perspective view of a display apparatus according to an embodiment.FIG. 2is a cross-sectional view taken along line A-A′ of the display apparatus ofFIG. 1.

Referring toFIG. 1, the display apparatus of an exemplary embodiment has a bent shape, as shown inFIG. 1. When the display apparatus has a bent shape, it may mean that a lower substrate100and an upper substrate500of the display apparatus are bent. A display apparatus having a bent shape may be formed by forming various layers on a substrate having a flat shape and bending the substrate, or may be formed by forming various layers on a bent substrate. However, for convenience, the display apparatus is illustrated as not being bent in some drawings.

The display apparatus according to an exemplary embodiment may be bent around a bending axis BAX that extends in one direction as shown inFIG. 1. In an exemplary embodiment, the bending axis BAX may extend in a first direction (e.g., a +y direction).

Referring toFIG. 2, the display apparatus according to an exemplary embodiment includes the lower substrate100and the upper substrate500opposing the lower substrate100. A liquid crystal layer200may be located between the lower substrate100and the upper substrate500. The lower substrate100may be bent around a first bending axis BAX1that extends in the first direction (e.g., the +y direction). The upper substrate500may be bent around a second bending axis BAX2that extends in a third direction (e.g., the +y direction). In an exemplary embodiment, the first direction (e.g., the +y direction) in which the first bending axis BAX1of the lower substrate100extends may be the same as the third direction (e.g., the +y direction) in which the second bending axis BAX2of the upper substrate500extends, and thus, the first bending axis BAX1and the second bending axis BAX2may be parallel to each other.

In the display apparatus according to an exemplary embodiment, the lower substrate100and the upper substrate500may be curved, as shown inFIG. 2. The lower substrate100and the upper substrate500may be adhered to each other and may be curved. In this case, curvatures of the lower substrate100and the upper substrate500may be different from each other. That is, the lower substrate100may have a first radius of curvature R1, and the upper substrate500may have a second radius of curvature R2.

In an exemplary embodiment, the first radius of curvature R1of the lower substrate100may be less than the second radius of curvature R2of the upper substrate500. In other words, a curvature of the lower substrate100may be greater than a curvature of the upper substrate500. That is, since the lower substrate100is closer to the center with respect to curvatures of the lower substrate100and the upper substrate, a curvature of the lower substrate100may be greater than a curvature of the upper substrate500.

FIG. 3is an enlarged plan view of a portion B ofFIG. 1.FIG. 4is a cross-sectional view taken along line C-C′ ofFIG. 3.

Referring toFIGS. 3 and 4, the display apparatus according to an exemplary embodiment may include a plurality of sub-pixels.FIG. 3illustrates the plurality of sub-pixels including a color filter300for emitting light of different colors. Each of the plurality of sub-pixels may be located in a pixel region P. The lower substrate100may have the pixel regions P.

The lower substrate100may be flexible and may be formed of plastic having high heat resistance and high durability.

The upper substrate500may be located over the lower substrate100so as to oppose the lower substrate100. The lower substrate100and the upper substrate500may face each other, and the upper substrate500may have a first surface500afacing the lower substrate100. Similar to the lower substrate100, the upper substrate500may be flexible and may be formed of plastic having high heat resistance and high durability.

For example, each of the lower substrate100and the upper substrate500may include any one selected from the group consisting of polyethersulfone (PES), polyacrylate (PA), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyarylate (PAR), polyimide (PI), polycarbonate (PC), cellulose triacetate, cellulose acetate propionate (CAP), poly(arylene ether sulfone), and a combination thereof. However, the present disclosure is not limited thereto, and each of the lower substrate100and the upper substrate500may be formed of any of various materials, such as a metal or glass. The lower substrate100and the upper substrate500may be formed of the same material or different materials.

A gate line (not shown), a gate electrode211, and a common line (not shown) are located on the lower substrate100. The gate line extends in one direction, and the gate electrode211is connected to the gate line. The gate electrode211may extend from the gate line, or may be a part of the gate line.

Each of the gate electrode211and the gate line may be formed to have a single-layered structure or a multi-layered structure by using at least one material selected from the group consisting of, for example, aluminum (Al), platinum (Pt), palladium (Pd), silver (Ag), magnesium (Mg), gold (Au), nickel (Ni), neodymium (Nd), iridium (Jr), chromium (Cr), lithium (Li), calcium (Ca), molybdenum (Mo), titanium (Ti), tungsten (W), and copper (Cu), in consideration of an adhesive force with an adjacent layer, a surface flatness of a stacked layer, and workability.

The common line may extend in the one direction so as to be parallel to the gate line.

A gate insulating film220may be located on the gate line, the gate electrode211, and the common line. The gate insulating film220may have a single-layered structure or a multi-layered structure by using, for example, silicon oxide and/or silicon nitride.

A semiconductor layer212may be located on the gate insulating film220, which is located on the gate electrode211. The semiconductor layer212may include an active layer212aformed of amorphous silicon and an ohmic contact layer212bformed of amorphous silicon doped with impurities.

A source electrode214and a drain electrode216may be located on the semiconductor layer212. The source electrode214and the drain electrode216may be spaced apart from each other, and a portion of the active layer212amay be exposed between the source electrode214and the drain electrode216. In this case, the ohmic contact layer212bmay have the same shape as that of the source electrode214and the drain electrode216.

Each of the source electrode214and the drain electrode216may be formed to have a single-layered structure or a multi-layered structure by using at least one material selected from the group consisting of, for example, Al, Pt, Pd, Ag, Mg, Au, Ni, Nd, Jr, Cr, Li, Ca, Mo, Ti, W, and Cu, in consideration of conductivity or the like.

The gate electrode211, the semiconductor layer212, the source electrode214, and the drain electrode216constitute a thin-film transistor (TFT), and the portion of the active layer212aexposed between the source electrode214and the drain electrode216form a channel of the TFT.

A data line (not shown) may be formed on the same layer as the source electrode214and the drain electrode216by using the same material as those of the source electrode214and the drain electrode216. The data line extends in a direction that intersects or is perpendicular to the one direction, and defines the pixel region P by intersecting the gate line. The data line may be connected to the source electrode214.

A protective layer230is formed on the source electrode214and the drain electrode216. The protective layer230may have a single-layered structure or a multi-layered structure by using, for example, silicon oxide and/or silicon nitride.

The color filter300may be located on the protective layer230. The color filter300may be located in the pixel region P so as to correspond to a pixel electrode. The color filter300may include at least one from among a red color filter300R, a blue color filter300B, a green color filter300G, and a white color filter, which may respectively correspond to each pixel region P. Although the red color filter300R, the green color filter300G, and the blue color filter300B are sequentially arranged in a +x direction inFIG. 3, the present disclosure is not limited thereto, and the color filters of the color filter300may be arranged in various ways.

Although not shown, a light-shielding layer may be located between color filters of the color filter300.

An organic film320may be located on the color filter300. The organic film320may protect various elements or lines, such as the color filter300and the TFT. The organic film320may be formed to have a single-layered structure or a multi-layered structure by using an acryl-based polymer such as polymethylmethacrylate (PMMA), polystyrene (PS), a polymer derivative having a phenol group, an imide-based polymer, an aryl ether-based polymer, an amide-based polymer, a fluorine-based polymer, a p-xylene-based polymer, a vinyl alcohol-based polymer, or a mixture thereof.

A column spacer400may be located on the first surface500aof the upper substrate500. The first surface500aof the upper substrate500facing the lower substrate100may be formed by forming the column spacer400on the first surface500aof the upper substrate500, and the upper substrate500may be adhered to the lower substrate100such that the first surface500aon which the column spacer400is formed faces the lower substrate100.

Although the column spacer400is located in each sub-pixel inFIG. 3, the column spacers400may be located in only some sub-pixels.

The column spacer400may maintain a cell gap, that is, an interval between the lower substrate100and the upper substrate500. The column spacer400of an exemplary embodiment may be a main column spacer for maintaining a cell gap, and although not shown, when pressure is applied to the upper substrate500or the lower substrate100, an auxiliary column spacer for preventing deformation may be further provided. The column spacer400of an exemplary embodiment is a main column spacer and may directly contact the organic film320that is an uppermost layer in a structure of the lower substrate100as shown inFIG. 4. However, the auxiliary column spacer may be spaced by a predetermined interval from the organic film320that is the uppermost layer in the structure of the lower substrate100.

Since the organic film320is the uppermost layer in the structure of the lower substrate100in an exemplary embodiment, the column spacer400contacts the organic film320. However, when another layer is located on the uppermost layer in the structure on the lower substrate100according to another exemplary embodiment, the column spacer400may contact the other layer.

The column spacer400may have a rectangular shape having a long axis and a short axis as shown inFIG. 3. However, a shape of the column spacer400is not limited thereto, and the column spacer400may have any of other shapes as long as the column spacer400has a long axis that extends in one direction.

The column spacer400according to an exemplary embodiment may extend in a second direction (e.g., the +x direction). The second direction (e.g., the +x direction) may intersect the first direction (e.g., the +y direction) and may intersect a direction in which the first bending axis BAX1extends. The second direction (e.g., the +x direction) may be perpendicular to the first direction (e.g., the +y direction) in an exemplary embodiment. In other words, the column spacer400may extend in a direction that intersects or is perpendicular to a direction in which the first bending axis BAX1extends.

FIG. 5is an enlarged view illustrating the column spacer400and a peripheral portion near the column spacer400ofFIG. 3.FIG. 5illustrates the color filter300overlapping a part of the column spacer400, and the color filter300may be at least one from among a red color filter, a blue color filter, a green color filter, and a white color filter.

Referring toFIGS. 5 and 3, the column spacer400may not overlap at least a portion of the color filter300. That is, the column spacer400may include a first portion400aand second portions400bcontacting the first portion400a. The first portion400amay be a portion of the column spacer400that overlaps the color filter300, and the second portions400bmay be portions of the column spacer400that do not overlap the color filter300.

As described above, the first portion400amay be defined as a portion of the column spacer400that overlaps the color filter300, and the second portions400bmay be defined as portions of the column spacer400that do not overlap the color filter300. It may be understood that the color filter300is not located in at least a portion of the pixel region P. That is, there is a portion of the pixel region P in which the color filter300is not located, and portions of the column spacer400located in this portion of the pixel region P are defined as the second portions400b. The color filter300is not located on the second portions400b, and the second portions400bmay be portions of the column spacer400that do not overlap the color filter300. As such, the first portion400amay be defined as an overlapping portion, and the second portions400bmay be defined as margin portions.

As shown inFIG. 5, the first portion400athat is an overlapping portion may be located at the center of the column spacer400, and the second portions400bthat are margin portions may be located at two sides of the first portion400a. Although the second portions400bare provided at two sides of the first portion400and have the same width inFIG. 5, according to another exemplary embodiment, the second portions400bmay be located only at one side of the first portion400a, or the second portions400bmay be located at two sides of the first portion400aand have different widths different from each other.

The column spacer400maintains a cell gap between the lower substrate100and the upper substrate500as described above. To this end, the column spacer400is formed to contact a layer that protrudes the most from among layers of the lower substrate100. In an exemplary embodiment, the first portion400aof the column spacer400overlaps a circuit unit including the TFT located on the lower substrate100and the color filter300located on the circuit unit, and directly contacts the organic film320that covers the color filter300.

The column spacer400according to an exemplary embodiment is located on the first surface500aof the upper substrate500. Since the column spacer400is located on the upper substrate500, the display apparatus having a bent shape, as shown inFIG. 1, may suffer misalignment in a process of bending the lower substrate100and the upper substrate500. This is because a curvature of the lower substrate100and a curvature of the upper substrate500differ in the actual process of bending the lower substrate100and the upper substrate500. Even though the color filter300located on the lower substrate100and the column spacer400located on the upper substrate500are aligned with each other before bending, since curvatures of the lower substrate100and the upper substrate500are different from each other, the color filter300and the column spacer400may be misaligned with each other in a process of bending the lower substrate100and the upper substrate500.

Accordingly, in a conventional curved display apparatus of the related art, this problem is solved by forming a column spacer on a lower substrate. However, once the column spacer is formed on the lower substrate, since the column spacer has to be formed on an uppermost layer from among layers formed on the lower substrate, when a height of the uppermost layer from among the layers formed on the lower substrate is excessively large, the column spacer falls downward to a peripheral portion, thereby making it difficult to form the column spacer with a sufficient height. Furthermore, when a width of an uppermost portion of the column spacer is not sufficiently large, the column spacer falls downward to a peripheral portion, thereby making it difficult to form the column spacer with a sufficient height.

In the display apparatus according to an exemplary embodiment, the column spacer400may be formed on the upper substrate500, and the column spacer400may extend in the second direction (e.g., the +x direction) that intersects the bending axis BAX, in order to prevent misalignment of the column spacer400in a process of bending the upper substrate500and the lower substrate100.

The first portion400aof the column spacer400that overlaps the color filter300may contact the organic film320located on the color filter300and may maintain a cell gap between the lower substrate100and the upper substrate500. The second portions400bof the column spacer400that do not overlap the color filter300may act as aligning margin portions for preventing misalignment when the column spacer400is moved during bending. Since the column spacer400has aligning margin portions as in an exemplary embodiment, a misalignment rate may be minimized and the display apparatus having a curved shape may be realized.

FIG. 6is a cross-sectional view of the display apparatus ofFIG. 1according to an exemplary embodiment.

InFIG. 6, the display apparatus is curved. A plurality of column spacers400may be located on the upper substrate500, and a plurality of color filters300may be located on the lower substrate100. The plurality of column spacers400and the plurality of color filters300may face each other. Although the plurality of color filters300are directly located on an upper surface of the lower substrate100inFIG. 6, it will be understood that a device layer including various lines such as a TFT may be further located between the lower substrate100and the plurality of color filters300.

Referring toFIG. 6, the display apparatus according to an exemplary embodiment may include a first column spacer400′ and a second column spacer400″. The second column spacer400″ may be located farther from a central axis CAX of the upper substrate500than the first column spacer400′. The first column spacer400′ and the second column spacer400″ may extend in the second direction (e.g., the +x direction) as described above. The first column spacer400′ may have a first length W1that extends in the second direction (e.g., the +x direction), and the second column spacer400″ may have a second length W2that extends in the second direction (e.g., the +x direction). In an exemplary embodiment, the second length W2of the second column spacer400″ may be greater than the first length W1of the first column spacer400′.

That is, lengths of the first column spacer400′ and the second column spacer400″ may increase away from the central axis CAX of the upper substrate500. In this case, the term ‘length’ of the column spacer400may refer to a length that extends in the second direction (e.g., the +x direction). Also, the central axis CAX of the upper substrate500is parallel to the second bending axis BAX2of the upper substrate500and may be defined as an axis that passes through the center of the upper substrate500.

When the upper substrate500and the lower substrate100are bent as in an exemplary embodiment, the risk of misalignment between the upper substrate500and the lower substrate100increases away from the center, that is, the central axis CAX, of the upper substrate500, and the center of the lower substrate100. Accordingly, a length of each of the column spacers400located on the upper substrate500may increase away from the central axis CAX of the upper substrate500in the present embodiment.

As shown inFIG. 6, the first column spacer400′ relatively close to the central axis CAX has the first length W1, and the second column spacer400″ relatively far from the central axis CAX has the second length W2. In this case, the second length W2of the second column spacer400″ may be greater than the first length W1of the first column spacer400′. Since the second length W2of the second column spacer400″ is greater than the first length W1of the first column spacer400′, the second column spacer400″ may have longer margin portions than those of the first column spacer400′.

That is, as shown inFIG. 6, the first column spacer400′ may have a first portion w11that overlaps the color filter300located under the first column spacer400′, and second portions w12that do not overlap the color filter300. The second column spacer400″ may have a first portion w21that overlaps the color filter300located under the second column spacer400″, and second portions w22that do not overlap the color filter300. In this case, the first portion w11of the first column spacer400′ and the first portion w21of the second column spacer400″ may be the same. However, because the second length W2of the second column spacer400″ is greater than the first length W1of the first column spacer400′, the second portions w22of the second column spacer400″ may be wider than the second portions w12of the first column spacer400′. Accordingly, when alignment of the upper substrate500and the lower substrate100shifts away from the central axis CAX, since the column spacer400has sufficient margin portions, misalignment between the supper substrate500and the lower substrate100may be minimized.

FIG. 7is a cross-sectional view of the display apparatus ofFIG. 1according to an exemplary embodiment.

InFIG. 7, the display apparatus is curved. The plurality of column spacers400may be located on the upper substrate500, and the plurality of color filters300may be located on the lower substrate100. Although the plurality of color filters300are located directly on a top surface of the lower substrate100inFIG. 7, it will be understood that a device layer including various lines such as a TFT may be further located between the lower substrate100and the plurality of color filters300.

Referring toFIG. 7, the display apparatus according to an exemplary embodiment may include the first column spacer400′ and the second column spacer400″. The second column spacer400″ may be farther from the central axis CAX of the upper substrate500than the first column spacer400′.

In an exemplary embodiment, a distance between the lower substrate100and the upper substrate500may increase away from the central axis CAX of the upper substrate500. Accordingly, a distance d2between the lower substrate100and a portion of the upper substrate500on which the second column spacer400″ is located may be greater than a distance d1between the lower substrate100and a portion of the upper substrate500on which the first column spacer400′ is located. This is results from a difference in curvature between the lower substrate100and the upper substrate500, as described above.

The first column spacer400′ may have a first height t1, and the second column spacer400″ may have a second height t2. In an exemplary embodiment, the second height t2of the second column spacer400″ may be greater than the first height t1of the first column spacer400′.

That is, heights of the first column spacer400′ and the second column spacer400″ may increase away from the central axis CAX of the upper substrate500. In this case, the term ‘height’ of the column spacer400may refer to a thickness extending along a Z-axis direction. The central axis CAX of the upper substrate500that is parallel to the second bending axis BAX2of the upper substrate500may be defined as an axis that passes through the center of the upper substrate500.

In the display apparatus according to an exemplary embodiment, the upper substrate500and the lower substrate100have different curvatures as described above. In this case, a curvature of the lower substrate100is greater than a curvature of the upper substrate500, and thus an interval between the upper substrate500and the lower substrate100increases away from the central axis CAX of the upper substrate500. Accordingly, the distance d2of the second column spacer400″ located farther from the central axis CAX of the upper substrate500may be greater than the distance d1of the first column spacer400′ located closer to the central axis CAX of the upper substrate500.

As described above, according to exemplary embodiments, a display apparatus that may simplify a process and may minimize a defect rate in a manufacturing process may be provided. However, the scope of the present disclosure is not so limited.

While the present disclosure has been particularly shown and described with reference to embodiments thereof, it will be understood by one of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the following claims.