Flexible display device

A flexible display device includes a flexible display panel, a driving circuit film, and a spacer. The flexible display panel includes a terminal part configured to receive a driving signal. The driving circuit film includes a base film and a driving chip on the base film. The driving chip being configured to generate the driving signal. The driving circuit film is coupled to the terminal part, is configured to apply the driving signal to the display panel, and bent toward a lower surface of the display panel. The spacer is on the driving circuit film and is configured to maintain a gap between the driving chip and the lower surface of the display panel.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application claims priority to and the benefit of Korean Patent Application No. 10-2013-0116574, filed on Sep. 30, 2013 in the Korean Intellectual Property Office, the entire content of which is hereby incorporated by reference.

BACKGROUND

The present disclosure relates to a flexible display device.

2. Description of the Related Art

A flexible display device has a flexible property to provide excellent transportability. In addition, because the flexible display device has a curved shape, it provides a three-dimensional effect and/or immersiveness to a user.

The flexible display device includes a display panel and a driving unit coupled to the display panel to drive the display panel. The display panel includes a flexible base substrate, such as a polyimide film, and a plurality of pixels disposed on the base substrate. The driving unit includes a driving circuit film coupled to the display panel.

Meanwhile, the display panel and the driving unit need to be reliably coupled so that no defect occurs during the operation (e.g., the functioning) of the flexible display device, even when the flexible display device is bent by the user.

SUMMARY

Aspects of embodiments of the present disclosure are directed toward a flexible display device having a flexible property to provide a curved display area. Aspects of embodiments of the present disclosure are also directed toward a flexible display device having an improved reliability.

According to an embodiments of the present disclosure, a flexible display device includes a flexible display panel, a driving circuit film, and a spacer. The flexible display panel includes a terminal part configured to receive a driving signal. The driving circuit film includes a base film and a driving chip on the base film, the driving chip being configured to generate the driving signal. The driving circuit film is coupled to the terminal part, configured to apply the driving signal to the display panel, and bent toward a lower surface of the display panel. The spacer is on the driving circuit film and configured to maintain a gap between the driving chip and the lower surface of the display panel.

A display area of the display panel and the lower surface of the display panel may have a curved shape.

The spacer may have a supporting surface contacting the lower surface of the display panel, and the supporting surface may have a curved shape corresponding to the curved shape of the lower surface.

The spacer may be between the lower surface of the display panel and the driving chip.

The spacer may extend past both sides of the driving chip.

The spacer may be between the lower surface of the display panel and the base film.

The spacer may include two spacers, and each spacer may be spaced from and adjacent to opposite ends of the driving chip.

The spacer may have a closed-loop shape to surround a perimeter of the driving chip.

The spacer may surround a portion of a perimeter of the driving chip.

The display panel may be curved along a first direction, and the terminal part may extend along the first direction.

A shorter side of the display panel may be curved along the first direction.

A longer side of the display panel may be curved along the first direction.

The driving chip may extend along the first direction.

The flexible display device may further include a driving circuit board adjacent to the lower surface of the display panel and electrically coupled to the driving circuit film, and the driving circuit film may be bent from the terminal part toward the driving circuit board.

The flexible display device may further include a window substrate including a light transmissive portion and covering the display panel, and a touch screen between the window substrate and the display panel and configured to detect a touch position generated on the window substrate, wherein the window substrate and the touch screen may be curved together with the display panel.

The display panel may include a display area having a curved shape, and the display area may have a concave shape.

The display panel may include a display area having a curved shape, and the display area may have a convex shape.

The display panel may be an organic electroluminescent display panel.

The spacer may have a closed-loop shape and may overlap a portion of the driving chip.

The spacer may extend along at least a portion of a side of the driving chip and may extend past the side and an opposite side of the driving chip.

As described above, the spacer is between the curved display panel and the driving circuit film. Therefore, the driving chip of the driving circuit film makes contact with the display panel. Although pressure may be applied to the driving chip, the pressure is prevented from being concentrated at a portion (e.g., a single portion or a point) of the driving chip, thereby preventing the driving chip from being damaged.

In addition, because the gap between the display panel and the driving chip is maintained by the spacer, the driving chip may not be substantially bent when the display panel is bent.

DETAILED DESCRIPTION

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 one or more intervening elements or layers may also be present. 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. Like reference designators refer to like elements throughout. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Hereinafter, the present disclosure will be explained in detail with reference to the accompanying drawings.

FIG. 1is an exploded perspective view showing a flexible display device according to an example embodiment of the present disclosure,FIG. 2Ais a cross-sectional view taken along a line I-I′ ofFIG. 1, andFIG. 2Bis a cross-sectional view taken along a line II-II′ ofFIG. 1.

Referring toFIGS. 1, 2A, and 2B, a flexible display device200includes a display panel50, a driving circuit film DF, a driving circuit board PB, a first adhesive member AS1, a touch screen TSP, a second adhesive member AS2, a window substrate WD, and a spacer SM. The flexible display device200may further include other elements, such as a housing to accommodate the above-described elements.

The display panel50displays an image (e.g., is configured to display an image) utilizing (e.g., using) light exiting through (e.g., emitted by) a display area DA. The display panel50has a flexible property and includes a display substrate10and a sealing part30. The display substrate10includes a flexible base substrate, such as a plastic substrate, and a plurality of pixels disposed on the base substrate. The sealing part30includes a plurality of inorganic layers and a plurality of organic layers that are alternately stacked with the inorganic layers to have the flexible property, and the sealing part30covers the display substrate10to protect and to prevent moisture and air from entering into the display substrate10.

In the present example embodiment, the display panel50may be an organic electroluminescent display panel. In this case, each of the pixels includes an anode, a cathode, and an organic light emitting layer disposed between the anode and the cathode to emit light, but the display panel50should not be limited to the organic electroluminescent display panel. For instance, the display panel50may be a liquid crystal display panel having a flexible property. In the case that the display panel50is the liquid crystal display panel, the display panel50may include an opposite substrate on which a common electrode is formed and a liquid crystal layer disposed between the opposite substrate and the display substrate10, and the opposite substrate may replace or take the place of the sealing part30. In addition, the display substrate10may include a plurality of pixel electrodes that forms an electric field in cooperation with the common electrode, and the flexible display device200may further include a backlight unit to provide light to the display panel50.

The display panel50may have a curved shape, curved along a first direction DR1, due to its flexible property. Thus, the display area DA displaying the image of the display panel50has a curved surface shape (e.g., a curved shape) that is curved along the first direction DR1. As a result, the flexible display device200displays the image having an improved three-dimensional effect and immersiveness through the display area DA with the curved surface shape.

The display panel50may include a terminal part PP, and a driving signal configured to drive the display panel50is applied to the display panel50through the terminal part PP. When a side of the display panel50, which is curved along the first direction DR1, is defined as a long side LE (e.g., a longer side of the display panel50), the terminal part PP extends along the long side LE of the display panel50and is disposed at one side of the display panel50.

The terminal part PP includes a plurality of signal lines and a plurality of bonding pads. The signal lines are electrically coupled to (e.g., electrically connected to) the pixels to transmit the driving signal to the pixels, and the bonding pads are electrically coupled to (e.g., electrically connected to) the signal lines to be electrically coupled to (e.g., electrically connected to) the driving circuit film DF.

The driving circuit film DF includes a flexible base film BS, a plurality of conductive lines, and a driving chip IC. The plurality of conductive lines and the driving chip IC are disposed on the base film BS. The driving circuit film DF is coupled to the display panel50and the driving circuit board PB, and thus the display panel50is electrically coupled to (e.g., electrically connected to) the driving circuit board PB through the driving circuit film DF.

In more detail, one end of the driving circuit film DF is electrically coupled to (e.g., electrically connected to) the terminal part PP, and the other end of the driving circuit film DF is electrically coupled to (e.g., electrically connected to) the driving circuit board PB. In manufacturing, because the driving circuit board PB is to be disposed adjacent to a lower surface LS of the display panel50(seeFIG. 2), the driving circuit film DF is bent or curved along a third direction DR3(e.g., a loop direction) from the terminal part PP toward the driving circuit board PB disposed under the terminal part PP as shown inFIG. 1. Therefore, the terminal part PP is electrically coupled to (e.g., electrically connected to) the driving circuit board PB by the driving circuit film DF with ease.

In the present example embodiment, the driving chip IC may be mounted on the base film BS in a flexible chip on film (COF) package, and the driving chip IC generates the driving signal. The driving chip IC may extend along the first direction DR1, in which the terminal part PP extends, such that output terminals of the driving chip IC may be easily coupled to (e.g., connected to) input terminals disposed on the terminal part PP.

The driving circuit board PB is disposed to face the window substrate WD, and the display panel50is disposed between the driving circuit board PB and the window substrate WD. The driving circuit board PB includes a timing controller to control the image displayed on the display panel50. In addition, the driving circuit board PB may further include a plurality of electrical components, which perform various functions of the flexible display device200, such as a camera module, a speaker module, etc.

The window substrate WD includes a light transmissive part111(e.g., a light transmissive portion) to transmit light therethrough and a light blocking part112(e.g., a light blocking portion) to block light (e.g., to prevent light from transmitting therethrough). The light transmissive part111is disposed to correspond to the display area DA, and the light blocking part112is disposed to correspond to an area surrounding the display area DA. Thus, light exiting from (e.g., light emitted by) the display panel50may be perceived by a user after passing through the light transmissive part111. In the present example embodiment, the light transmissive part111may have a flat shape, and the light blocking part112may have a thickness thicker than that of the light transmissive part111and may have a convex shape.

The touch screen TSP is coupled to the window substrate WD to detect a touch position on the window substrate WD (e.g., the touch screen TSP is configured to detect a touch position on the window substrate WD), at which a touch event occurs. The touch screen TSP may be an electrostatic capacitive touch screen, however, it should not be limited thereto. For instance, the touch screen TSP may be a resistive film touch screen, an ultrasonic touch screen, or an infrared touch screen.

The first adhesive member AS1is disposed between the window substrate WD and the touch screen TSP, and the second adhesive member AS2is disposed between the touch screen TSP and the display panel50. The first adhesive member AS1bonds the touch screen TSP to the window substrate WD, and the second adhesive member AS2bonds the touch screen TSP to the display panel50. In the present example embodiment, each of the first and second adhesive members AS1and AS2may be an adhesive film having a light transmissive property. For instance, each of the first and second members AS1and AS2may be an optically clear adhesive (OCA).

The window substrate WD, the touch screen TSP, the first adhesive member AS1, and the second adhesive member AS2are curved along the first direction DR1to correspond to the curved shape of the display panel50.

The spacer SM is disposed on the driving circuit film DF to maintain a gap GP between the driving chip IC and the lower surface LS of the display panel50. The spacer SM is disposed on the base film BS and is between the base film BS and the lower surface LS. The spacer SM may include two spacers SM that are each spaced from (e.g., spaced apart from) the driving chip IC to be disposed adjacent to both ends of the driving chip IC.

As shown inFIG. 2B, because the display panel50is curved along the first direction DR1, not only does the display area DA have the curved shape, but the lower surface LS also has the curved surface shape, curved along the first direction DR1. Thus, a supporting surface SS of the spacer SM, which makes contact with the lower surface LS, has a curved surface shape corresponding to the curved surface shape of the lower surface LS. In addition, a height of the lower surface LS above the base film BS may vary with respect to the base film BS, and thus, the spacer SM has a variable thickness corresponding to the height of the lower surface LS.

In the present example embodiment, because the driving chip IC includes a semiconductor substrate, such as a wafer, the driving chip IC may not be flexible. In the case that the driving chip IC is not flexible, an upper surface US of the driving chip IC facing the lower substrate LS has a substantially flat shape. Thus, when the driving chip IC makes contact with the lower substrate LS, only a portion of the upper surface US makes contact with the lower substrate LS (that is, less than the entire upper surface US makes contact with the lower substrate LS).

As described above, in the case that the upper surface US makes partial contact with the lower surface LS and a pressure is applied to the driving chip IC from an external source, the spacer SM alleviates the pressure to prevent or protect the pressure from being concentrated at an area where the upper surface US makes contact with the lower surface LS (e.g., the spacer SM extends or lengthens to prevent pressure from being concentrated at a portion of the driving chip IC).

Different from the above-mentioned embodiments of the present disclosure, in a comparative example in which the spacer SM is omitted from the flexible display device200and the pressure is applied to the driving chip IC, the driving chip IC may be damaged or bent along the curved surface shape of the lower surface LS due to the pressure. According to the present example embodiment, however, the spacer SM alleviates the pressure and maintains the gap GP between the driving chip IC and the lower surface LS, thereby preventing the driving circuit IC from being damaged or bent.

The spacer SM may include an insulating material, such as polymer resin. For instance, the spacer SM may include an elastic material, such as rubber or silicon, to alleviate the pressure applied to the driving circuit film DF. According to another example embodiment, the spacer SM may include an adhesive material to bond to the base film BS and the lower surface LS.

FIG. 3Ais a plan view showing a driving circuit film and a spacer included in a flexible display device according to another example embodiment of the present disclosure, andFIG. 3Bis a cross-sectional view showing the flexible display device including the driving circuit film and the spacer shown inFIG. 3A. InFIGS. 3A and 3B, the same reference designators denote the same elements as those inFIGS. 1, 2A, and 2B, and thus the detailed descriptions of the same elements may be omitted.

Referring toFIGS. 3A and 3B, a flexible display device201includes a display panel50, a driving circuit film DF, and a spacer SM1. The spacer SM1is disposed on a driving chip IC and is between a lower surface LS of the display panel50and the driving chip IC. The spacer SM1extends beyond both sides of (e.g., is overlapped with both ends of) the driving chip IC when viewed in a plan view as shown inFIG. 3A.

Because the spacer SM1makes contact with the lower surface LS, a pressure applied to the driving chip IC is alleviated by the spacer SM1, thereby preventing the driving chip IC from being damaged due to the pressure applied to the driving chip IC (that is, because the spacer SM1is between the lower surface LS and the driving chip IC, it alleviates pressure applied to the driving chip IC). In addition, the spacer SM1maintains a gap GP between the driving chip IC and the lower surface LS, and thus the driving chip IC may be prevented from being curved or cracked along the curved surface shape of the lower surface LS.

FIG. 4Ais a plan view showing a driving circuit film and a spacer included in a flexible display device according to another example embodiment of the present disclosure, andFIG. 4Bis a cross-sectional view showing the flexible display device including the driving circuit film and the spacer shown inFIG. 4A. InFIGS. 4A and 4B, the same reference designators denote the same elements as those shown in the previously described embodiments, and thus the detailed descriptions of the same elements may be omitted.

Referring toFIGS. 4A and 4B, a flexible display device202includes a display panel50, a driving circuit film DF, and a spacer SM2. In the present example embodiment, the spacer SM2may have a closed-loop shape (e.g., a rectangular shape) surrounding a driving chip IC when viewed in a plan view.

Similar to the embodiments previously described, the spacer SM2according to the present example embodiment is disposed on the driving circuit film DF to maintain a gap between the driving chip IC and a lower surface LS of the display panel50. Because the driving chip IC makes partial contact with the lower surface LS, a pressure is prevented or protected from being concentrated at the driving chip IC. As a result, the driving chip IC is prevented or protected from being curved or cracked by the pressure even though the display panel50is curved.

FIGS. 5A, 5B, and 5Care plan views each showing a driving circuit film and a spacer included a flexible display device according to other example embodiments of the present disclosure. InFIGS. 5A, 5B, and 5C, the same reference designators denote the same elements as those shown in the previously described embodiments, and thus the detailed descriptions of the same elements may be omitted.

Referring toFIG. 5A, a spacer SM3-1is disposed on a driving circuit film DF, has a closed-loop shape (e.g., a rectangular shape) surrounding a portion of a driving chip IC, and is partially overlapped with the driving chip IC when viewed in a plan view.

Referring toFIG. 5B, a spacer SM3-2is disposed on a driving circuit film DF. In addition, the spacer SM3-2is spaced from (e.g., spaced apart from and/or does not overlap) and partially surrounds a driving chip IC, and a portion of the spacer SM3-2, which corresponds to one of two longer sides of the driving chip IC, is opened when viewed in a plan view (that is, the spacer SM3-2substantially surrounds three sides of the driving chip IC).

Referring toFIG. 5C, a spacer SM3-3is disposed on a driving circuit film DF and is partially overlapped with a driving chip IC when viewed in a plan view. Also, a portion of the spacer SM3-3, which corresponds to one of two longer sides of the driving chip IC, is opened when viewed in a plan view (that is, the spacer SM3-3extends along three sides of the driving chip IC).

In the present example embodiments shown inFIGS. 5A to 5C, the spacers SM3-1, SM3-2, and SM3-3maintain a gap between the driving chip IC and a display panel50. Therefore, a pressure applied to the driving chip IC is alleviated by the spacers SM3-1, SM3-2, and SM3-3, and the gap between the driving chip IC and the display panel50is maintained by the spacers SM3-1, SM3-2, and SM3-3. Thus, the driving chip IC may be prevented or protected from being bent due to the curved shape of the display panel50.

FIG. 6Ais a plan view showing a driving circuit film and a spacer included in a flexible display device according to another example embodiment of the present disclosure, andFIG. 6Bis a cross-sectional view showing the flexible display device including the driving circuit film and the spacer shown inFIG. 6A. InFIGS. 6A and 6B, the same reference designators denote the same elements as those shown in the previously described embodiments, and thus the detailed descriptions of the same elements may be omitted.

Referring toFIGS. 6A and 6B, a flexible display device203includes a display panel50, a driving circuit film DF, and a spacer SM4. In the example embodiment described with reference toFIG. 2B, the display area DA (refer toFIG. 2B) has the curved surface shape of which edge portions are more convex than a center portion (e.g., the lower surface of the display panel50of the embodiment illustrated inFIG. 2has a concave curved surface shape corresponding to the display area DA). However, in the present example embodiments shown inFIGS. 6A and 6B, a display area DA of the display panel50has a curved surface shape of which a center portion is more convex than edge portions. In this case, a lower surface LS of the display panel50has a convex curved surface shape corresponding to the display area DA.

The spacer SM4is disposed on the driving circuit film DF to maintain a gap between a driving chip IC and a lower surface LS of the display panel50. A supporting surface SS of the spacer SM4, which makes contact with the lower surface LS, has a convex shape corresponding to the shape of the lower surface LS. Thus, a pressure applied to the driving chip IC is alleviated by the spacer SM4to prevent the driving chip IC from being damaged, and the gap between the driving chip IC and the lower surface LS is maintained by the spacer SM4to prevent the driving chip IC from being bent due to the shape of the lower surface LS.

FIG. 7Ais an exploded perspective view showing a flexible display device according to another example embodiment of the present disclosure, andFIG. 7Bis a cross-sectional view taken along the line III-III′ ofFIG. 7A.

Referring toFIGS. 7A and 7B, a flexible display device204includes a display panel50′, a driving circuit film DF′, a driving circuit board PB′, a first adhesive member AS1′, a touch screen TSP′, a second adhesive member AS2′, a window substrate WD′, and a spacer SM5.

The display panel50′ has a flexible property and is curved along a first direction DR1. Thus, a display area DA′ displaying an image in the display panel50′ has a curved surface shape along the first direction DR1. According to the example embodiments described with reference toFIGS. 1, 2A, and 2B, the long side LE (refer toFIG. 1) of the display panel50(refer toFIG. 1) is curved along the first direction DR1, however a short side SE of the display panel50′ (e.g., a shorter side of the display panel50′) is curved along the first direction DR1in the present example embodiment shown inFIGS. 7A and 7B.

Each of the driving circuit film DF′, the driving circuit board PB′, the first adhesive member AS1′, the touch screen TSP′, the second adhesive member AS2′, and the window substrate WD′ may be curved along the first direction DR1along with the display panel50′.

Similar to the spacer SM described with reference toFIG. 2B, the spacer SM5is disposed on the driving circuit film DF′ to maintain a gap GP between a driving chip IC and a lower surface LS of the display panel50′. As described earlier, when the display panel50′ is curved along the first direction DR1, not only is the display area DA′ curved along the first direction DR1, but the lower surface LS is also curved along the first direction DR1to have a curved surface shape. Thus, a supporting surface SS of the spacer SM5making contact with the lower surface LS has a curved surface shape corresponding to the curved surface shape of the lower surface LS. In addition, because a height of the lower surface LS may vary with respect to the base film BS, the spacer SM5has a variable thickness depending on the height of the lower surface LS (that is, the spacer SM5has a variable thickness depending on a distance between the lower surface LS and the base film BS).

Because the spacer SM5makes contact with the lower surface LS, a pressure applied to the driving chip IC is alleviated by the spacer SM5, and thus the driving chip IC is prevented from being damaged by the pressure applied to the driving chip IC. In addition, because the gap GP between the driving chip IC and the lower surface LS is maintained by the spacer SM5, the driving chip IC is prevented or protected from being bent and cracked along with the curved surface shape of the lower surface LS.