Patent Description:
Organic light-emitting display devices have many advantages such as their excellent luminance, driving voltage, response speed characteristics and capability of realizing multiple colors, and thus have been applied to various products, including smart phones. A typical organic light-emitting display includes a display panel including organic light-emitting elements. In each of the organic light-emitting elements, a cathode electrode and an anode electrode are arranged to face each other with an organic light-emitting layer interposed therebetween. In response to a voltage applied to the cathode and anode electrodes, visible light is generated in the organic light emitting layer to which the cathode and anode electrodes are both connected.

A panel bottom sheet is attached to the bottom of a display panel of a display device. The panel bottom sheet may include various functional sheets for protecting the display panel against heat or an external shock. Also, the panel bottom sheet may further include an auxiliary input device (such as a digitizer) or a driving device that is difficult to place on the top of the display panel.

The auxiliary device such as a digitizer may include wiring patterns. The wiring patterns are generally formed of a metal. When the display device is used in an outdoor environment, the wiring patterns may become visible on the display screen of the display device because of reflected light by the wiring patterns which cause a serious deterioration of the display quality of the display device. <CIT> discloses a display device with a panel bottom sheet including a first base, a first light-absorbing layer, an interlayer bonding layer and a wiring pattern portion. <CIT> discloses an illumination device and display device. The illumination device is a backlight device provided as a side surface emission type LED. <CIT> and <CIT> disclose a laminate comprising an adhesive layer. Further reference is made to <CIT>, <CIT> and <CIT>.

The present invention is defined by the features of claim <NUM>. The dependent claims describe preferred embodiments.

The present invention provides a display device capable of reducing the visibility of wiring patterns of a panel bottom sheet.

However, exemplary embodiments of the present invention are not restricted to those set forth herein. The above and other exemplary embodiments 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.

According to the present invention, the visibility of wiring patterns can be reduced by reducing light reflected by wiring patterns or height differences formed by the wiring patterns.

Other features and exemplary embodiments may be apparent from the following detailed description, the drawings, and the claims.

The above and other exemplary embodiments and features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:.

Advantages and features of the present invention and methods of accomplishing the same may be understood more readily by reference to the following detailed description of exemplary embodiments and the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of the present invention to those skilled in the art, and the present invention will only be defined within the scope of the appended claims.

Cases where elements or layers are referred to as being located "on" other elements or layers include all the cases where other layers or other elements are interposed directly on or between other elements. Meanwhile, cases where the elements are "directly on" indicate that no other element or layer is interposed therebetween. Same reference numerals refer to the same constituent elements throughout the specification. Term 'and/or" includes each and every combination of one or more of the referenced items.

These terms are only used to distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the present invention. Exemplary embodiments of the present invention will hereinafter be described with reference to the accompanying drawings.

<FIG> is a perspective view of a display device according to an exemplary embodiment of the present invention. <FIG> is an exploded perspective view of the display device according to the exemplary embodiment of <FIG>. <FIG> is a cross-sectional view taken along line III-III' of <FIG>.

Referring to <FIG>, a display device <NUM> includes a display panel <NUM> and a panel bottom sheet <NUM> disposed below the display panel <NUM>. The display device <NUM> may further include a window <NUM> disposed above the display panel <NUM>. The display device <NUM> may further include a bracket <NUM> disposed below the panel bottom sheet <NUM>.

Unless specified otherwise, the terms "upper", "top" or "top surface", and "above," as used herein, refer to a display surface side of the display panel <NUM>, and the terms "lower", "bottom" or "bottom surface", or "below," as used herein, refer to an opposite side to the display surface side of the display panel <NUM>.

The display device <NUM> may be rectangular in a plan view. The display device <NUM> may have two long sides and two short sides. The long sides and the short sides of the display device <NUM> meet at a right angle. Alternatively, as illustrated in <FIG>, the long sides and the short sides of the display device <NUM> meet to form curved surfaces, as illustrated in <FIG>. The planar shape of the display device <NUM> is not particularly limited, and the display device <NUM> may be in a shape other than a rectangular shape such as, for example, a circular shape, in a plan view.

The display panel <NUM> is a panel for displaying an image and may be, for example, an organic light-emitting display panel. The display panel <NUM> will hereinafter be described as being an organic light-emitting display panel, but various types of display panels other than an organic light-emitting display panel, such as, for example, a liquid crystal display (LCD) panel, an electrophoretic display panel, or the like may be used as the display panel <NUM>.

The display panel <NUM> includes a plurality of organic light-emitting elements disposed on a substrate. The substrate may be a rigid substrate formed of, for example, glass, or may be a flexible substrate formed of, for example, polyimide (PI). In a case where a PI substrate is used as the substrate, the display panel <NUM> may be a flexible panel such as a bendable panel, a foldable panel and a rollable panel.

The window <NUM> is disposed above the display panel <NUM>. The window <NUM> protects the display panel <NUM> from an external shock from the display surface side and allows the transmission of light emitted from the display panel <NUM>. The window <NUM> may be formed of, for example, glass.

The window <NUM> may be disposed to overlap with the display panel <NUM> and to cover the entire surface of the display panel <NUM>. The window <NUM> may be larger in size than the display panel <NUM>. For example, the window <NUM> may protrude beyond the display panel <NUM> on both short sides of the display device <NUM>. The window <NUM> may also protrude beyond the display panel <NUM> on both long sides of the display device <NUM>, but the distance by which the window <NUM> may protrude beyond the display panel <NUM> on both short sides of the display device <NUM> may be greater than the distance by which the window <NUM> may protrude beyond the display panel <NUM> on both long sides of the display device <NUM>.

In one exemplary embodiment, a touch member <NUM> may be disposed between the display panel <NUM> and the window <NUM>. The touch member <NUM> may be a rigid panel type, a flexible panel type, or a film type. The touch member <NUM> may have substantially the same size as the display panel <NUM> and may be disposed to overlap with the display panel <NUM> so that the sides thereof can be aligned with the sides of the display panel <NUM>, but the present invention is not limited thereto. The display panel <NUM> and the touch member <NUM> may be bonded together by a transparent bonding layer <NUM> such as an optically clear adhesive (OCA) or an optically clear resin (OCR), and the touch member <NUM> and the window <NUM> may be bonded together by a transparent bonding layer <NUM> such as an OCA or an OCR. The touch member <NUM> may be omitted, in which case, the display panel <NUM> and the window <NUM> may be bonded together by an OCA or an OCR. In one exemplary embodiment, the display panel <NUM> may include a touch member <NUM>.

The panel bottom sheet <NUM> is disposed below the display panel <NUM>. The panel bottom sheet <NUM> includes a top bonding layer (<NUM> of <FIG>) at an uppermost portion thereof and may be attached to the bottom surface of the display panel <NUM> via the top bonding layer <NUM>.

The panel bottom sheet <NUM> has substantially the same size as the display panel <NUM> and is disposed to overlap with the display panel <NUM> so that the sides thereof can be aligned with the sides of the display panel <NUM>. The panel bottom sheet <NUM> may perform a heat dissipation function, an electromagnetic shielding function, a pattern visibility prevention function, a grounding function, a buffer function, a reinforcement function, and/or a digitizing function, and may include at least one functional layer having at least one of these functions of the panel bottom sheet <NUM>. The functional layer may be provided in various forms such as a layer, a film, a sheet, a plate, or a panel.

The panel bottom sheet <NUM> may include one or more functional layers. In a case where the panel bottom sheet <NUM> includes a plurality of functional layers, the functional layers may be stacked to overlap with one another. The functional layers may be stacked directly on one another or may be stacked indirectly via bonding layers.

Various example of the panel bottom sheet <NUM> will be described later.

The bracket <NUM> is disposed below the panel bottom sheet <NUM>. The bracket <NUM> receives the window <NUM>, the touch member <NUM>, the display panel <NUM>, and the panel bottom sheet <NUM> therein. The bracket <NUM> may have a bottom surface and sidewalls. The bottom surface of the bracket <NUM> is opposite to the bottom surface of the panel bottom sheet <NUM>, and the sidewalls of the bracket <NUM> faces the sides of each of the window <NUM>, the touch member <NUM>, the display panel <NUM>, and the panel bottom sheet <NUM>. The panel bottom sheet <NUM> includes a bottom bonding member <NUM> of <FIG> at a lowermost portion thereof and may be attached to the bottom surface of the bracket <NUM> via the bottom bonding member <NUM>.

Although not specifically illustrated, waterproof tapes may be disposed along the edges of the bottom surface of the bracket <NUM>. The waterproof tapes disposed along the long sides of the bracket <NUM> may be attached to the bottom surface of the panel bottom sheet <NUM>, and the waterproof tapes disposed along the short sides of the bracket <NUM> may be attached to the bottom surface of the window <NUM>.

In one exemplary embodiment, the display device <NUM> may include a flat area FA and bending areas BA connected to the flat area FA and disposed adjacent to the flat area FA. The flat area FA may be disposed substantially on one plane. The bending areas BA are not on the same plane as the flat area FA. For example, the bending areas BA may be bent downwardly from the plane where the flat area FA is disposed.

In one exemplary embodiment, the bending areas BA may have outwardly convex surfaces. In another exemplary embodiment, the bending areas BA may have flat surfaces that are disposed on a plane having a predetermined angle with respect to the plane of the flat area FA.

The bending areas BA may be provided on both long sides of the display device <NUM>, which is rectangular, or on one of the long sides of the display device <NUM>. Although not specifically illustrated, the display device <NUM> may also be bent on the short sides thereof.

The display panel <NUM>, the touch member <NUM>, the window <NUM>, and the panel bottom sheet <NUM> may all be positioned in both the flat area FA and the bending areas BA.

In an alternative exemplary embodiment, the display device <NUM> may be a flat display device only having the flat area FA. Thus, all the aspects of the display device <NUM> discussed herein, except for those specifically related to the bending areas BA, may be directly applicable not only to a bendable display device, but also to a flat display device.

The panel bottom sheet <NUM> will hereinafter be described in further detail.

<FIG> is a cross-sectional view of a panel bottom sheet according to an exemplary embodiment of the present invention. For convenience, <FIG> illustrates a generally flat panel bottom sheet. The flat panel bottom sheet of <FIG> maintains its shape when attached to a flat display panel. However, when attached to a curved display panel, the flat panel bottom sheet may be bent along the curved display panel and may have a flat area and bending areas. This directly applies not only to the panel bottom sheet of <FIG>, but also to panel bottom sheets of <FIG> and <FIG>.

Referring to <FIG>, a panel bottom sheet <NUM> includes a cover panel portion <NUM> and a wiring pattern portion <NUM> disposed below the cover panel portion <NUM>.

The cover panel portion <NUM> includes a cover base <NUM>, a first light-absorbing layer <NUM>, a top bonding layer <NUM> disposed on the top surface of the first light-absorbing layer <NUM>, a first release film <NUM> disposed on the top surface of the top bonding layer <NUM>, and a first interlayer bonding layer <NUM> disposed on the bottom surface of the cover base <NUM>.

The cover base <NUM> may be formed of polyethylene terephthalate (PET), PI, polycarbonate (PC), polyethylene (PE), polypropylene (PP), polysulfone (PSF), polymethyl methacrylate (PMMA), triacetyl cellulose (TAC), or a cyclo-olefin polymer (COP).

The first light-absorbing layer <NUM> is disposed on the top surface of the cover base <NUM>. The first light-absorbing layer <NUM> is disposed directly on the top surface of the cover base <NUM>. The first light-absorbing layer <NUM> is disposed to completely cover wiring patterns 200a. The first light-absorbing layer <NUM> is disposed on the entire top surface of the cover base <NUM>.

The first light-absorbing layer <NUM> blocks transmission of light therethrough and thus prevents the wiring pattern 200a of a wiring pattern portion <NUM> from being visible from thereabove. The first light-absorbing layer <NUM> comprises a light-absorbing material. The first light-absorbing layer <NUM> comprises a black ink. The first light-absorbing layer <NUM> may be formed on the top surface of the cover base <NUM> by a coating or printing method. The first light-absorbing layer <NUM> will be described later in detail.

The top bonding layer <NUM> is disposed on the top surface of the first light-absorbing layer <NUM>. The top bonding layer <NUM> attaches the panel bottom sheet <NUM> to the bottom surface of the display panel <NUM>. The top bonding layer <NUM> may include an adhesive layer or a resin layer. For example, the top bonding layer <NUM> may comprise a polymer material such as a silicone polymer, a urethane polymer, a silicone-urethane (SU) hybrid polymer, an acrylic polymer, an isocyanate polymer, a polyvinyl alcohol polymer, a gelatin polymer, a vinyl polymer, a latex polymer, a polyester polymer, or a water-based polyester polymer.

The first release film <NUM> is disposed on the top surface of the top bonding layer <NUM>. The first release film <NUM> covers and protects the top surface of the top bonding layer <NUM> when the panel bottom sheet <NUM> is yet to be attached to the display panel <NUM>. Then, when the panel bottom sheet <NUM> is attached to the display panel <NUM>, the first release film <NUM> is peeled off and thus exposes the top surface of the top bonding layer <NUM>, which becomes a bonding surface.

The first release film <NUM> may be placed in contact with the top bonding member <NUM>, but may not be completely attached on the top bonding member <NUM> so as to be able to be peeled off later. The first release film <NUM> may comprise PET, PC, PI, or paper. In order to improve the release force of the first release film <NUM>, the top surface of the first release film <NUM> may be treated with a silicon solution or coated with a release coating layer, but the present invention is not limited to this.

In some exemplary embodiments, the bottom surface of the first release film <NUM> may have an embossed shape. The embossed shape of the bottom surface of the first release film <NUM> may be transferred to the top surface of the top bonding layer <NUM>, which is attached to the first release film <NUM>, and as a result, the top surface of the top bonding layer <NUM> may have an embossed shape that is complementary to the embossed shape of the bottom surface of the first release film <NUM>. In a case where the top surface of the top bonding layer <NUM> has an embossed shape, the embossed shape of the top surface of the top bonding layer <NUM> serves as an air passage during the attachment of the panel bottom sheet <NUM> to the bottom surface of the display panel <NUM>, and may thus reduce air bubbles between the display panel <NUM> and the panel bottom sheet <NUM>. Once the top bonding layer <NUM> is completely attached to the bottom of the display panel <NUM>, the embossed shape of the top surface of the top bonding layer <NUM> may collapse and may be planarized, as illustrated in <FIG>.

The first interlayer bonding layer <NUM> is disposed on the bottom surface of the cover base <NUM>. The first interlayer bonding layer <NUM> may bond the cover base <NUM> and the wiring pattern portion <NUM> together. That is, the first interlayer bonding layer <NUM> may bond the cover panel portion <NUM> to the wiring pattern portion <NUM>, which is disposed below the cover panel portion <NUM>. In the exemplary embodiment of <FIG>, the first interlayer bonding layer <NUM> may be included in the cover panel portion <NUM>, but alternatively, the first interlayer bonding layer <NUM> may be included in the wiring pattern portion <NUM> or may be provided as a separate member.

The first interlayer bonding layer <NUM> may be formed of one of the aforementioned examples of the material of the top bonding layer <NUM>.

The wiring pattern portion <NUM> may include the wiring patterns 200a and a plurality of insulating layers (200b and 200c) covering the wiring patterns 200a from above and below, respectively. Specifically, the wiring pattern portion <NUM> may include a first insulating layer 200b, the wiring patterns 200a disposed on the top surface of the first insulating layer 200b, and a second insulating layer 200c covering the top surfaces of the wiring patterns 200a. The wiring patterns 200a cover some parts of the top surface of the first insulating layer 200b and expose other parts of the top surface of the first insulating layer 200b. The second insulating layer 200c may be disposed not only on the top surface and the sides of each of the wiring patterns 200a, but also on the exposed parts of the top surfaces of the first insulating layer 200b.

The wiring patterns 200a may comprise a metal material such as, for example, copper (Cu), silver (Ag), nickel (Ni), or tungsten (W). The wiring patterns 200a may be formed as single films or stacks of a plurality of films. In one exemplary embodiment, each of the wiring patterns 200a may be a double layered film including a lower Cu film and an upper Cu film. The wiring patterns 200a may be wirings or electrodes transmitting signals. Also, the wiring patterns 200a may be floating wirings or electrodes.

The first and second insulating layers 200b and 200c may comprise an organic insulating material, an inorganic insulating material, or an organic-inorganic hybrid insulating material or may comprise a bonding material such as an adhesive material.

In one exemplary embodiment, the wiring pattern portion <NUM> may be a digitizer. The digitizer, unlike an input device such as a keyboard or a mouse, receives information regarding a position on a screen, designated by a user. The digitizer recognizes the movement of, for example, a stylus pen, and converts the recognized movement into a digital signal. The digitizer may be provided in the form of a thin film or a panel. In a case where the wiring pattern portion <NUM> is a digitizer, the structure of the digitizer will be described later with reference to <FIG>. However, the present invention is not limited to this. That is, alternatively, other various members with wiring patterns, such as a printed circuit board (PCB) or a flexible PCB (FPCB), may be used as the wiring pattern portion <NUM>.

The cover base <NUM>, the first light-absorbing layer <NUM>, the top bonding layer <NUM>, the first release film <NUM>, and the first interlayer bonding layer <NUM> of the cover panel portion <NUM> and the first and second insulating layers 200b and 200c of the wiring pattern portion <NUM> may all overlap with one another, and the sides of each of the cover base <NUM>, the first light-absorbing layer <NUM>, the top bonding layer <NUM>, the first release film <NUM>, and the first interlayer bonding layer <NUM> of the cover panel portion <NUM> and the sides of each of the first and second insulating layers 200b and 200c of the wiring pattern portion <NUM> may all be aligned. The sides of each of the cover base <NUM>, the first light-absorbing layer <NUM>, the top bonding layer <NUM>, the first release film <NUM>, and the first interlayer bonding layer <NUM> of the cover panel portion <NUM> and the sides of each of the first and second insulating layers 200b and 200c of the wiring pattern portion <NUM> may be cutting planes. For example, in a case where the panel bottom sheet <NUM> is obtained by fabricating and cutting a mother panel bottom sheet, the sides of each of the first light-absorbing layer <NUM>, the top bonding layer <NUM>, the first release film <NUM>, and the first interlayer bonding layer <NUM> of the cover panel portion <NUM> and the sides of each of the first and second insulating layers 200b and 200c of the wiring pattern portion <NUM> may all be cutting planes and may all be aligned.

In a case where the wiring patterns 200a are formed of a material such as a metal, the wiring patterns 200a may have a high reflectivity and may thus be able to well reflect light incident from thereabove. However, if the light reflected by the wiring patterns 200a is emitted toward a display screen, the wiring patterns 200a may be recognized by a user, thereby adversely affecting the display quality of the display device <NUM>.

Since the wiring patterns 200a are formed only on parts of the top surface of the first insulating layer 200b, height differences may be formed between areas where the wiring patterns 200a are disposed and areas where the wiring patterns 200a are not disposed. The height differences may be transferred onto the layers formed on the wiring patterns 200a. That is, for convenience, <FIG> illustrates an example in which the top surface of the second insulating layer 200c is flat, but the second insulating layer 200c may be conformally formed on the wiring patterns 200a and may thus have an uneven top surface, rather than a flat top surface. The uneven top surface of the second insulating layer 200c may affect the layers formed on the second insulating layer 200c, i.e., the first interlayer bonding layer <NUM>, the cover base <NUM>, and the first light-absorbing layer <NUM>, and as a result, the surfaces of the first interlayer bonding layer <NUM>, the cover base <NUM>, and the first light-absorbing layer <NUM> may become at least partially uneven. The uneven surfaces of the first interlayer bonding layer <NUM>, the cover base <NUM>, and the first light-absorbing layer <NUM> may affect the reflectance or the reflection angle of incident light (i.e., the emission direction of reflected light) so that particular patterns may become visible on the display screen.

The first light-absorbing layer <NUM> prevents reflected light from being emitted toward the display screen. The first light-absorbing layer <NUM> primarily prevents light from being downwardly transmitted therethrough and also prevents reflected light from being upwardly transmitted therethrough.

In order to prevent the wiring patterns 200a from becoming visible, the first light-absorbing layer <NUM> may be formed to be sufficiently thick. If the thickness of the first light-absorbing layer <NUM> is about <NUM> µm or more, the first light-absorbing layer <NUM> may have an optical density (OD) of <NUM> or more and may thus be able to sufficiently lower the reflectivity of the wiring patterns 200a with respect to the display screen, and as a result, the wiring patterns 200a may be prevented from becoming visible. If the thickness of the first light-absorbing layer <NUM> is about <NUM> or more, the first light-absorbing layer <NUM> may have an OD of <NUM> or more, and as a result, the wiring patterns 200a may be prevented from becoming visible, even if height differences formed by the wiring patterns 200a make the surfaces of the layers formed on the wiring patterns 200a to have uneven surface.

The thicker the first light-absorbing layer <NUM>, the higher the OD of the first light-absorbing layer <NUM>. However, the thickness of the first light-absorbing layer <NUM> may preferably be set to be about <NUM> or less in consideration of coating or printing efficiency, durability, and the thickness of the display device <NUM>.

In the embodiment of <FIG> and in accordance with the present invention, the first light-absorbing layer <NUM> is disposed on the top surface of the cover base <NUM>.

<FIG> is a cross-sectional view illustrating the path of light in a panel bottom sheet in which a first light-absorbing layer is disposed on the top surface of the cover base. <FIG> is a cross-sectional view illustrating the path of light in a panel bottom sheet in which a first light-absorbing layer is disposed on the bottom surface of a cover base, different from the present invention. <FIG> and <FIG> illustrate a top bonding layer <NUM> as being attached on the bottom surface of a display panel <NUM>. In each of the panel bottom sheets of <FIG> and <FIG>, a first release film <NUM> is already removed and thus no longer exists, and the top surface of the top bonding layer <NUM> is planarized.

Referring to <FIG>, light L1 is obliquely incident on a display panel <NUM> and arrives at a first light-absorbing layer <NUM> through the top bonding layer <NUM>. The first light-absorbing layer <NUM> absorbs some of the light L1 and transmits some of the light L1 downwardly therethrough. The light transmitted downwardly through the first light-absorbing layer <NUM> is reflected by wiring patterns 200a to travel upwardly. The light traveling upwardly arrives at the first light-absorbing layer <NUM>, and the first light-absorbing layer <NUM> absorbs at least some of the light arriving thereat. Some of the light not absorbed by the first light-absorbing layer <NUM>, i.e., light L2, may be emitted upwardly through the top bonding layer <NUM>. Since a considerable amount of light can be absorbed by the first light-absorbing layer <NUM>, the amount of light (i.e., the light L2) reflected from the wiring patterns 200a and then finally emitted through the first light-absorbing layer 120is much smaller than the amount of original incident light (i.e., the light L1).

Referring to <FIG>, light L1 is obliquely incident on a display panel <NUM> and arrives at a first light-absorbing layer <NUM> through the top bonding layer <NUM> and a cover base <NUM>. The light L1 is reflected at the interface between the top bonding layer <NUM> and the cover base <NUM>. The reflectance and reflection angle of the reflected light, i.e., light L3, may vary depending on the degree of unevenness on the surface of the cover base <NUM>.

Light transmitted through the cover base <NUM> arrives at the first light-absorbing layer <NUM>, and some of the light arriving at the first light-absorbing layer <NUM>, i.e., light L2, may be absorbed by the first light-absorbing layer <NUM> and some of the light arriving at the first light-absorbing layer <NUM> may be transmitted through the first light-absorbing layer <NUM> and reflected by the wiring patterns 200a upwardly along substantially the same path as the light L2 of <FIG>.

In response to the light L1 being obliquely incident on the side of the display panel <NUM>, the panel bottom sheet of <FIG> emits more light than the panel bottom sheet of <FIG> by as much as the light L3. Since light (such as the light L2 and the light L3) emitted from the panel bottom sheet of <FIG> adversely affects the visibility of wiring patterns 200a, the panel bottom sheet of <FIG>, which emits a relatively small amount of light, may be more advantageous than the panel bottom sheet of <FIG> in terms of preventing the wiring patterns 200a from becoming visible. The absolute amount of the light L3 reflected at the interface between the top bonding layer <NUM> and the cover base <NUM> is not small even when the difference in refractive index between the top bonding layer <NUM> and the cover base <NUM> is small, and the visibility of the wiring patterns 200a may be varied by even a slight difference in emitted light. Thus, the difference between the panel bottom sheet of <FIG> and the panel bottom sheet of <FIG> may produce a significant difference in the visibility of the wiring patterns 200a. Accordingly, in general circumstances, one of the panel bottom sheet of <FIG> and the panel bottom sheet of <FIG> may be chosen, but in a case where the wiring patterns 200a of the panel bottom sheet of <FIG> appear visible, the panel bottom sheet of <FIG> may be considered instead of the panel bottom sheet of <FIG>.

Panel bottom sheets according to other exemplary embodiments of the present invention will hereinafter be described. In <FIG>, like reference numerals denote like elements, and thus, descriptions thereof will be omitted or at least simplified.

<FIG> is a cross-sectional view of a panel bottom sheet according to another exemplary embodiment of the present invention. <FIG> shows that a plurality of light-absorbing layers can be provided.

Referring to <FIG>, a panel bottom sheet <NUM> differs from the panel bottom sheet <NUM> of <FIG> in that a cover panel portion <NUM> further includes a second light-absorbing layer <NUM> disposed on the bottom surface of a cover base <NUM>. That is, a first light-absorbing layer <NUM> is disposed on the top surface of the cover base <NUM>, and a second light-absorbing layer <NUM> is disposed on the bottom surface of the cover base <NUM>. A first interlayer bonding layer <NUM> is disposed on the bottom surface of the second light-absorbing layer <NUM>. The second light-absorbing layer <NUM> may be formed of the same material as the first light-absorbing layer <NUM>, but the present invention is not limited thereto. The second light-absorbing layer <NUM> may have the same size, and the sides of the second light-absorbing layer <NUM> may be aligned with the sides of the first light-absorbing layer <NUM>.

In the exemplary embodiment of <FIG>, the first and second light-absorbing layers <NUM> and <NUM> are disposed on the top surface and the bottom surface, respectively, of the cover base <NUM>, and light L1 obliquely incident on a display panel <NUM> may be absorbed by both the first and second light-absorbing layers <NUM> and <NUM>. Accordingly, the amount of reflected light finally emitted can be reduced. The light absorption ratio of the panel bottom sheet <NUM> is generally proportional to the sum of the thicknesses of the first and second light-absorbing layers <NUM> and <NUM>. Thus, in order for the panel bottom sheet <NUM> to have substantially the same OD as the panel bottom sheet <NUM> according to the exemplary embodiment of <FIG>, the sum of the thicknesses of the first and second light-absorbing layers <NUM> and <NUM> may be set to be in the range of about <NUM> µm to about <NUM> µm. Alternatively, each of the thicknesses of the first and second light-absorbing layers <NUM> and <NUM> may be set to be in the range of about <NUM> µm to about <NUM> µm, in which case, the OD of the panel bottom sheet <NUM> may be further improved if the sum of the thicknesses of the first and second light-absorbing layers <NUM> and <NUM> exceeds <NUM> µm. For example, the first and second light-absorbing layers <NUM> and <NUM> may have the same thickness of about <NUM> µm, but the present invention is not limited thereto.

Referring to <FIG>, a cover panel portion <NUM> of a panel bottom sheet <NUM> includes first and second light-absorbing layers <NUM> and <NUM>.

The first light-absorbing layer <NUM> includes first through fourth unit layers 122a through 122d, which are sequentially stacked on the top surface of a cover base <NUM> along an upward direction. A top bonding layer <NUM> is disposed on the top surface of the fourth unit layer 122d.

The second light-absorbing layer <NUM> includes first through fourth unit layers 123a through 123d, which are sequentially stacked on the bottom surface of the cover base <NUM> along a downward direction. A first interlayer bonding layer <NUM> is disposed on the bottom surface of the fourth unit layer 123d.

The first through fourth unit layers 122a through 122d and the first through fourth unit layers 123a through 123d may be formed of the same material as the first light-absorbing layer <NUM>. The first through fourth unit layers 122a through 122d and the first through fourth unit layers 123a through 123d may comprise the same material, but the present invention is not limited thereto.

The first through fourth unit layers 122a through 122d and the first through fourth unit layers 123a through 123d may all have the same thickness. The thickness of the first light-absorbing layer <NUM> may be determined by the sum of the thicknesses of the first through fourth unit layers 122a through 122d, and the thickness of the second light-absorbing layer <NUM> may be determined by the sum of the thicknesses of the first through fourth unit layers 123a through 123d. If the first through fourth unit layers 122a through 122d and the first through fourth unit layers 123a through 123d all have the same thickness of, for example, about <NUM> µm, the thicknesses of the first and second light-absorbing layers <NUM> and <NUM> may both be about <NUM> µm.

The first through fourth unit layers 122a through 122d and the first through fourth unit layers 123a through 123d may be formed by printing. The first unit layers 122a and 123a may be <NUM>-degree printed layers, the second unit layers 122b and 123b may be <NUM>-degree printed layers, the third unit layers 122c and 123c may be <NUM>-degree printed layers, and the fourth unit layers 122d and 123d may be <NUM>-degree printed layers. More vivid colors can be obtained by printing the same colors multiple times. In the exemplary embodiment of <FIG>, the first through fourth unit layers 122a through 122d and the first through fourth unit layers 123a through 123d may all appear black, thereby achieving a vivid black color, and this means that the light absorption efficiency of the first and second light-absorbing layers <NUM> and <NUM> can be further improved. The first through fourth unit layers 122a through 122d and the first through fourth unit layers 123a through 123d may also be formed by a method other than printing.

In the exemplary embodiment of <FIG>, the first and second light-absorbing layers <NUM> and <NUM> both include four unit layers, but the present invention is not limited thereto. That is, the first and second light-absorbing layers <NUM> and <NUM> may include two, three, or five or more unit layers. Also, the number of unit layers of the first light-absorbing layer <NUM> may differ from the number of unit layers of the second light-absorbing layer <NUM>. Since the OD of the cover panel portion <NUM> is generally proportional to the sum of the thicknesses of the unit layers of the first light-absorbing layer <NUM> and the thicknesses of the unit layers of the second light-absorbing layer <NUM>, the first and second light-absorbing layers <NUM> and <NUM> may be formed by stacking various numbers of unit layers in accordance with a desired OD.

<FIG> and <FIG> are cross-sectional views of panel bottom sheets according to other exemplary embodiments of the present invention. Referring to <FIG> and <FIG>, panel bottom sheets <NUM> and <NUM> differ from the panel bottom sheet <NUM> according to the exemplary embodiment of <FIG> in that they further include a buffer portion <NUM>. The buffer portion <NUM> may include a buffer member <NUM> and a second interlayer bonding layer <NUM>.

The buffer member <NUM> absorbs an external shock and thus prevents the display device <NUM> from being damaged. The buffer member <NUM> may be formed as a single film or a stack of a plurality of films. The buffer member <NUM> may be formed of a material with elasticity such as, for example, a polyurethane (PU) or PE resin. The buffer member <NUM> may be a cushion layer.

The second interlayer bonding layer <NUM> bonds the buffer member <NUM> to another member and may be formed of one of the aforementioned examples of the material of the top bonding layer <NUM> of the panel bottom sheet <NUM> according to the exemplary embodiment of <FIG>. In the exemplary embodiments of <FIG> and <FIG>, the second interlayer bonding layer <NUM> may be included in the buffer portion <NUM>. Alternatively, the second interlayer bonding layer <NUM> may be included in another member or may be provided as a separate member.

In one exemplary embodiment, the buffer member <NUM> may be disposed between a cover panel portion <NUM> and a wiring pattern portion <NUM>, as illustrated in <FIG>. In this example, the second interlayer bonding layer <NUM> is disposed on the bottom surface of the buffer member <NUM> and is bonded to the wiring pattern portion <NUM>. The top surface of the buffer member <NUM> is bonded to a first interlayer bonding layer <NUM>.

In another exemplary embodiment, the buffer member <NUM> may be disposed below the wiring pattern portion <NUM>, as illustrated in <FIG>. In this example, the second interlayer bonding layer <NUM> is disposed on the top surface of the buffer member <NUM> and is bonded to the wiring pattern portion <NUM>.

<FIG> is a cross-sectional view of a panel bottom sheet according to another exemplary embodiment of the present invention. Referring to <FIG>, a panel bottom sheet <NUM> differs from the panel bottom sheet <NUM> according to the exemplary embodiment of <FIG> in that it further includes a heat dissipation portion <NUM>.

Specifically, the heat dissipation portion <NUM> may be disposed below a wiring pattern portion <NUM>. The heat dissipation portion <NUM> may include at least one heat dissipation layer. <FIG> illustrates an example in which the heat dissipation portion <NUM> includes two heat dissipation layers, i.e., first and second heat dissipation layers <NUM> and <NUM>.

The first and second heat dissipation layers <NUM> and <NUM> may be formed of the same material or may be formed of materials having different heat dissipation characteristics. The first heat dissipation layer <NUM> may include, for example, a metal film such as a Cu or Ag film. The second heat dissipation layer <NUM> may include, for example, graphite or carbon nanotubes (CNTs).

The second heat dissipation layer <NUM> may be disposed above the first heat dissipation layer <NUM>. The first and second heat dissipation layers <NUM> and <NUM> may be disposed to overlap with each other. The second heat dissipation layer <NUM> may be smaller in size than the first heat dissipation layer <NUM>, and the sides of the second heat dissipation layer <NUM> may be positioned more inwardly than the sides of the first heat dissipation layer <NUM>. For example, in response to the panel bottom sheet <NUM> being bonded to a bent display panel <NUM>, the first heat dissipation layer <NUM> may be disposed in both a flat area FA and bending areas BA. On the other hand, the second heat dissipation layer <NUM> may be disposed in the flat area FA, but not in the bending areas BA. This type of arrangement may be employed in a case where the second heat dissipation layer <NUM> is formed of a material with relatively poor bending characteristics such as, for example, graphite, or is too thick to be properly bent.

The second heat dissipation layer <NUM> is covered by a third interlayer bonding layer <NUM>, and the third interlayer bonding layer <NUM> is bonded to the wiring pattern portion <NUM>, which is disposed above the third interlayer bonding layer <NUM>. A fourth interlayer bonding layer <NUM> may be interposed between the second heat dissipation layer <NUM> and the first heat dissipation layer <NUM> and may bond the second heat dissipation layer <NUM> and the first heat dissipation layer <NUM> together. The second heat dissipation layer <NUM> may expose edge portions of the fourth interlayer bonding layer <NUM>, and the top surfaces of the edge portions of the fourth interlayer bonding layer <NUM> may be placed in direct contact with, and bonded to, the third interlayer bonding layer <NUM>, which is disposed above the fourth interlayer bonding layer <NUM>.

The heat dissipation portion <NUM> may further include a bottom bonding member <NUM> and a second release film <NUM>. The bottom bonding member <NUM> may be disposed on the bottom surface of the first heat dissipation layer <NUM> and bonds the panel bottom sheet <NUM> to a bracket <NUM>, which may be disposed below the panel bottom sheet <NUM>, as illustrated in <FIG>.

In one exemplary embodiment, the bottom bonding member <NUM> may be provided as a double-sided tape. The double-sided tape includes a tape base <NUM>, a first bonding layer <NUM> disposed on the bottom surface of the tape base <NUM>, and a second bonding layer <NUM> disposed on the top surface of the tape base <NUM>. The tape base <NUM> may be formed of PET, PI, PC, PE, PP, PSF, PMMA, TAC, or a COP. The first and second bonding layers <NUM> and <NUM> may be formed of one of the aforementioned examples of the material of the top bonding layer <NUM> of the panel bottom sheet <NUM> according to the exemplary embodiment of <FIG>. Alternatively, the bottom bonding member <NUM> may include a single bonding layer or a plurality of bonding layers without having the tape base <NUM>.

The second release film <NUM> is disposed on the bottom surface of the bottom bonding member <NUM> and protects the bottom surface of the bottom bonding member <NUM>. The second release film <NUM> may be substantially the same as the first release film <NUM>. <FIG> illustrates an example in which the second release film <NUM> has no embossed shape on the top surface thereof, but alternatively, the second release film <NUM>, like the first release film <NUM> having an embossed shape on the bottom surface thereof, may have an embossed shape on the top surface thereof.

The bottom bonding member <NUM>, like the second heat dissipation layer <NUM>, may be disposed in the flat area FA, but not in the bending areas BA. The sides of the bottom bonding member <NUM> may be aligned with, or positioned more inwardly than, the sides of the second heat dissipation layer <NUM>. A waterproof tape (not illustrated) may be attached to part of the bottom surface of the first heat dissipation layer <NUM> exposed by the bottom bonding member <NUM> and may be bonded to the bracket <NUM>.

In the exemplary embodiment of <FIG>, the bottom bonding member <NUM> is included in the heat dissipation portion <NUM>, but may be provided as a separate member. Alternatively, the bottom bonding member <NUM> may be provided at lowermost portions of panel bottom sheets having various stack structures to bond the panel bottom sheets to the bracket <NUM>. For example, the bottom bonding member <NUM> may be disposed below the wiring pattern portion of the panel bottom sheet <NUM> according to the exemplary embodiment of <FIG>.

A digitizer, which is used as the wiring pattern portion <NUM> of each of the panel bottom sheets <NUM> through <NUM> according to the exemplary embodiments of <FIG> and <FIG>, will hereinafter be described.

<FIG> is a layout view of a digitizer according to an exemplary embodiment of the present invention. <FIG> is a cross-sectional view taken along line XIII-XIII' of <FIG>. <FIG> is a cross-sectional view showing the digitizer according to the exemplary embodiment of <FIG> in a bent state.

Referring to <FIG>, a digitizer <NUM> includes a base layer <NUM>, a first wiring layer <NUM> disposed on the top surface of the base layer <NUM>, and a second wiring layer <NUM> disposed on the bottom surface of the base layer <NUM>. The digitizer <NUM> may further include a first coverlayer <NUM> covering the first wiring layer <NUM> from above, a second coverlayer <NUM> covering the second wiring layer <NUM> from below, a signal shielding sheet <NUM> disposed below the second coverlayer <NUM>, and a fifth interlayer bonding layer <NUM> interposed between the signal shielding sheet <NUM> and the second coverlayer <NUM>. The top surface of the first coverlayer <NUM> may be bonded to the bottom surface of the second interlayer bonding layer <NUM> of <FIG>, and the bottom surface of the signal shielding sheet <NUM> may be bonded to the third interlayer bonding layer <NUM> of <FIG>.

The base layer <NUM> provides space in which to form the first and second wiring layers <NUM> and <NUM>. The base layer <NUM> may be formed of an insulating material. The base layer <NUM> may comprise an inorganic material such as glass, or may comprise an organic material in order to realize flexibleness. For example, the base layer <NUM> may comprise at least one of PI, PET, PC, PE, PP, PSF, PMMA, TAC, and a COP. For example, the base layer <NUM> may comprise PI.

The first and second wiring layers <NUM> and <NUM> are disposed on the top surface and the bottom surface, respectively, of the base layer <NUM>. The first and second wiring layers <NUM> and <NUM> may be formed directly on the base layer <NUM>. The first and second wiring layers <NUM> and <NUM> may comprise a metal material such as Cu, Ag, Ni, or W. <FIG> illustrate an example in which the first and second wiring layers <NUM> and <NUM> are single films, but alternatively, each of the first and second wiring layers <NUM> and <NUM> may be formed as a stack of a plurality of films. For example, each of the first and second wiring layers <NUM> and <NUM> may include a stack of first and second Cu films.

The first wiring layer <NUM> includes a plurality of first wiring patterns <NUM> and first ground wirings <NUM>. The second wiring layer <NUM> includes a plurality of second wiring patterns <NUM> and second ground wirings <NUM>.

The first wiring patterns <NUM> may extend in a first direction, for example, a long-side direction. The second wiring patterns <NUM> may extend in a second direction, which intersects the first direction, for example, a short-side direction. The first wiring patterns <NUM> and the second wiring patterns <NUM> may be disposed mostly in a flat area FA, but not in bending areas BA. Alternatively, some of the first wiring patterns <NUM> and some of the second wiring patterns <NUM> may be disposed in the bending areas BA.

A number of first wiring patterns <NUM> may form a wiring pattern group, and a number of second wiring patterns <NUM> may form a wiring pattern group. For example, as illustrated in <FIG>, five first or second wiring patterns <NUM> or <NUM> may form a single wiring pattern group, but the present invention is not limited thereto. That is, various numbers of first or second wiring patterns <NUM> or <NUM> form various numbers of wiring pattern groups.

The distance between wiring pattern groups formed by the first wiring patterns <NUM> or between wiring pattern groups formed by the second wiring patterns <NUM> may be greater than the distance between the first wiring patterns <NUM> or between the second wiring patterns <NUM>. In a case where the distance between wiring patterns or wiring pattern groups is large in a particular region, height differences formed in the particular region may be reflected onto the top of the particular region, and as a result, the wiring patterns or the wiring pattern groups may become visible. However, as already mentioned above, since the first light-absorbing layer <NUM> and/or the second light-absorbing layer <NUM> of <FIG> may be disposed on the first wiring patterns <NUM> and the second wiring patterns <NUM>, the first wiring patterns <NUM> and the second wiring patterns <NUM> can be prevented from becoming visible.

Areas where the wiring pattern groups formed by the first wiring patterns <NUM> and the wiring pattern groups formed by the second wiring patterns <NUM> intersect each other may become coordinate electrode portions CE, which are basic units for position recognition.

The first ground wirings <NUM> and the second grounding wirings <NUM> are disposed in the bending areas BA. The first ground wirings <NUM> and the second grounding wirings <NUM> may extend in the same direction as the first wiring patterns <NUM>, i.e., in the long-side direction. The first ground wirings <NUM> and the second grounding wirings <NUM> may generally overlap with each other. <FIG> illustrate an example in which the first ground wirings <NUM> and the second grounding wirings <NUM> completely overlap with each other in a plan view, but the present invention is not limited thereto.

Each of the first ground wirings <NUM> and the second grounding wirings <NUM> include slits SL. The slits SL may extend in the first direction. Each of the first ground wirings <NUM> and the second grounding wirings <NUM> may be divided into sub-wirings, which are separated from one another by the slits SL but are connected to one another at the end of the corresponding first or second ground wiring <NUM> or <NUM>, but the present invention is not limited thereto. That is, the slits SL may be surrounded by each of the first ground wirings <NUM> and the second grounding wirings <NUM>, but the present invention is not limited thereto. Alternatively, the slits SL may extend to the end of each of the first ground wirings <NUM> and the second grounding wirings <NUM> so that the sub-wirings of each of the first ground wirings <NUM> and the second grounding wirings <NUM> may be separated from one another, even at the end of the corresponding first or second ground wiring <NUM> or <NUM>. <FIG> illustrate an example in which two slits SL are provided in each of the first ground wirings <NUM> and the second ground wirings <NUM> to divide the corresponding first or second ground wirings <NUM> or <NUM> into three sub-wirings, but alternatively, only one slit SL or three or more slits SL may be provided in each of the first ground wirings <NUM> and the second ground wirings <NUM>. The slits SL reduce bending stress.

Specifically, the first ground wirings <NUM> and the second ground wirings <NUM> have a relatively wide width. For example, the width of the first ground wirings <NUM> and the second ground wirings <NUM> may be greater than the width of the first wiring patterns <NUM> and the second wiring patterns <NUM>. If the first ground wirings <NUM> and the second ground wirings <NUM>, which are both disposed in the bending areas BA, have too large width, a considerable amount of stress may be applied to the bending areas BA during the attachment of a panel bottom sheet including the digitizer <NUM> to a display panel <NUM>. For example, in a case where the first ground wirings <NUM> and the second ground wirings <NUM> are formed of Cu, the bending resistance of the first ground wirings <NUM> and the second ground wirings <NUM> is relatively strong so that the panel bottom sheet including the digitizer <NUM> may not be able to be properly attached to the display panel <NUM> or that the bonding force between the panel bottom sheet including the digitizer <NUM> and the display panel <NUM> may weaken later.

In the exemplary embodiment of <FIG>, the slits SL are formed in each of the first ground wirings <NUM> and the second ground wirings <NUM>, thereby offering the same effect of reducing the width of the first ground wirings <NUM> and the second ground wirings <NUM>. That is, as illustrated in <FIG>, flexibility can be secured in the slits SL where no wiring material is provided, and as a result, the first ground wirings <NUM> and the second ground wirings <NUM> can be properly bent.

The slits SL may also help prevent each of the first ground wirings <NUM> and the second ground wirings <NUM> from becoming visible. Specifically, in a case where the first ground wirings <NUM> and the second ground wirings <NUM> are formed to have no slits SL, the first ground wirings <NUM> and the second ground wirings <NUM> are highly likely to be visible from the outside because of strong reflections that may occur over their relatively large areas. On the other hand, in the exemplary embodiment of <FIG>, each of the first ground wirings <NUM> and the second ground wirings <NUM> is divided into sub-wirings by the slits SL. As a result, the reflectivity of the first ground wirings <NUM> and the second ground wirings <NUM> may be reduced, and as a result, the visibility of the first ground wirings <NUM> and the second ground wirings <NUM> may also be reduced.

A pad portion PAD is provided at one side of the base layer <NUM>. An external device such as a PCB or a FPCB is connected to the pad portion PAD. The first wiring patterns <NUM> and the second wiring patterns <NUM> are connected to the pad portion PAD so that the digitizer <NUM> can be communicated with the external device.

The pad portion PAD may comprise the material of the first wiring layer <NUM> and/or the material of the second wiring layer <NUM>. In a case where the pad portion PAD comprises both the materials of the first wiring layer <NUM> and the second wiring layer <NUM>, a PCB or FPC may be connected to the pad portion PAD, the first wiring patterns <NUM> and the first ground wirings <NUM> may be connected to part of the pad portion PAD corresponding to the first wiring layer <NUM>, and the second wiring patterns <NUM> and the second ground wirings <NUM> may be connected to part of the pad portion PAD corresponding to the second wiring layer <NUM>.

In one exemplary embodiment, the first and second wiring layers <NUM> and <NUM> may be electrically connected through via holes, and this will hereinafter be described with reference to <FIG>.

<FIG> is a cross-sectional view of a digitizer according to another exemplary embodiment of the present invention. Referring to <FIG>, a digitizer <NUM> may further include via holes VIA formed through a base layer <NUM> and connecting first and second wiring layers <NUM> and <NUM>.

For example, a first ground wiring <NUM> of the first wiring layer <NUM> and a second ground wiring <NUM> of the second wiring layer <NUM> are all wirings for grounding and may be shortcircuited. The via holes VIA electrically connect the first and second ground wirings <NUM> and <NUM> to short-circuit the first and second ground wirings <NUM> and <NUM>. The via holes VIA may be formed in sub-wirings, respectively, of each of the first and second ground wirings <NUM> and <NUM>, divided by slits SL, as illustrated in <FIG>. Alternatively, the via holes VIA may be formed only in part of each of the first and second ground wirings <NUM> and <NUM>.

The via holes VIA may be filled with the material of the first wiring layer <NUM>. In this case, the material of the first wiring layer <NUM> and the material filling the via holes VIA may not have any physical boundary therebetween. Alternatively, the via holes VIA may be filled with the material of the second wiring layer <NUM>. Still alternatively, the via holes VIA may be filled with a material other than the materials of the first and second wiring layers <NUM> and <NUM>. In this example, the boundaries between the material filling the via holes VIA and the first and second ground wirings <NUM> and <NUM> may be observed.

Although not specifically illustrated, the via holes VIA may also be formed through the base layer <NUM> through which the pad portions PAD which is formed of the material of the first wiring layer <NUM> and the second wiring patterns <NUM> are connected. For example, in a case where a pad portion PAD comprises only the material of the first wiring layer <NUM>, the pad portion PAD through which a control signal or an output signal of the second wiring patterns <NUM> is transmitted is connected to the second wiring patterns <NUM> through the via holes VIA. The first wiring layer <NUM> connected to the second wiring pattern <NUM> via the via holes VIA may be disposed on the outer side of the first wiring pattern <NUM>, which forms a coordinate electrode portion CE, for example, in or around a bent portion BA.

First and second coverlayers <NUM> and <NUM>, which protect the first and second wiring layers <NUM> and <NUM>, respectively, may be formed of an insulating material. The first and second coverlayers <NUM> and <NUM> may be formed as single films or stacks of a plurality of films.

For example, the first coverlayer <NUM> may include a first coverlayer bonding layer <NUM> and a first coverlayer insulating layer <NUM> sequentially stacked in an upward direction, and the second coverlayer <NUM> may include a second coverlayer bonding layer <NUM> and a second coverlayer insulating layer <NUM> sequentially stacked in a downward direction.

The first and second coverlayer insulating layers <NUM> and <NUM> may be formed of at least one of PI, PET, PC, PE, PP, PSF, PMMA, TAC, and a COP. In one exemplary embodiment, the first and second coverlayer insulating layers <NUM> and <NUM> may comprise PI. The first and second coverlayer bonding layers <NUM> and <NUM> may be formed of one of the aforementioned examples of the material of the top bonding layer <NUM> of the panel bottom sheet <NUM> according to the exemplary embodiment of <FIG>. The first and second coverlayer bonding layers <NUM> and <NUM> may not be provided.

A signal shielding sheet <NUM> is disposed below the first and second wiring layers <NUM> and <NUM> and prevents signal interference. For example, in a case where an external device such as a PCB, FPCB, or a driving chip is disposed below a bracket <NUM>, the external device may cause signal interference during the input of signals with a stylus pen, and the signal shielding sheet <NUM> prevents this type of signal interference. The signal shielding sheet <NUM> may be formed of a ferromagnetic material comprising iron oxide such as, for example, ferrite.

<FIG> is a layout view of a digitizer according to another exemplary embodiment of the present invention.

Referring to <FIG>, a digitizer <NUM> differs from the digitizer <NUM> according to the exemplary embodiment of <FIG> in that it further includes a plurality of first floating wiring patterns 221a and a plurality of second floating wiring patterns 231a.

The first floating wiring patterns 221a are disposed among wiring pattern groups formed by first wiring patterns <NUM>, and the second floating wiring patterns 231a are disposed among wiring pattern groups formed by second wiring patterns <NUM>. Since the first or second floating wiring patterns 221a or 231a are disposed among the wiring pattern groups formed by the first or second wiring patterns <NUM> or <NUM>, the gaps among the wiring pattern groups formed by the first or second wiring patterns <NUM> or <NUM> are filled. Accordingly, the same effect of reducing the distance between the wiring pattern groups formed by the first or second wiring patterns <NUM> or <NUM> can be offered, and as a result, the visibility of the first wiring patterns <NUM> and the second wiring patterns <NUM> can be reduced.

Example <NUM> different from the present invention and examples <NUM> through <NUM> and Experimental Examples <NUM> and <NUM> in accordance with the present invention will hereinafter be described.

The bottom surface of a PET base was coated with black ink to a thickness of <NUM> µm twice to form a black ink layer having a thickness of <NUM>µm. Thereafter, an adhesive was respectively applied to the top surface of the black ink layer to a thickness of <NUM> µm and to the bottom surface of the PET base to a thickness of <NUM> µm, thereby obtaining a cover panel film.

A cover panel film was fabricated using the same method used to obtain the cover panel film according to Example <NUM> except for coating the bottom surface of a PET base with black ink to a thickness of <NUM> µm three times to form a black ink layer having a thickness of <NUM>µm.

The top surface and the bottom surface of a PET base were both coated with black ink to a thickness of <NUM> µm twice to form a black ink layer having a thickness of <NUM>µm on each of the top and bottom surfaces of the PET base. Thereafter, an adhesive was respectively applied to the top surface of the black ink layer on the top surface of the PET base to a thickness of <NUM> µm and to the bottom surface of the black ink layer on the bottom surface of the PET base to a thickness of <NUM> µm, thereby obtaining a cover panel film.

A cover panel film was fabricated using the same method used to obtain the cover panel film according to Example <NUM> except for coating both the top surface and the bottom surface of a PET base with black ink to a thickness of <NUM> µm three times to form a black ink layer having a thickness of <NUM> µm on each of the top and bottom surfaces of the PET base.

A cover panel film was fabricated using the same method used to obtain the cover panel film according to Example <NUM> except for coating both the top surface and the bottom surface of a PET base with black ink to a thickness of <NUM> µm four times to form a black ink layer having a thickness of <NUM> µm on each of the top and bottom surfaces of the PET base.

The ODs of the cover panel films according to Examples <NUM> through <NUM> were measured, and the results of the measurement are as shown in Table <NUM> below. OD is a logarithmic value of the ratio of an amount I1 of light transmitted through a particular medium to an amount I0 of light incident upon the particular medium, i.e., I1/I0. The higher the OD, the smaller the amount of light transmission, and the greater the amount of optical absorption.

Reflectance measurement was conducted by placing a digitizer below each of the cover panel films according to Examples <NUM> and <NUM>. Referring to Table <NUM> below, "Top" denotes a location near one short side of each of the cover panel films according to Examples <NUM> and <NUM>, which are rectangular in shape, "Middle" denotes a location in the middle of each of the cover panel films according to Examples <NUM> and <NUM>, and "Bottom" denotes a location near the other short side of each of the cover panel films according to Examples <NUM> and <NUM>. Reflectance measurements obtained from the cover panel films according to Examples <NUM> and <NUM> are as shown in Table <NUM> below.

Claim 1:
A display device (<NUM>), comprising:
a display panel (<NUM>),
the display panel (<NUM>) including a light emitting surface through which an image is displayed and an opposing surface opposite to the light emitting surface;
a window (<NUM>) disposed on the light emitting surface of the display panel (<NUM>); and
a panel bottom sheet (<NUM>-<NUM>) having substantially the same size as the display panel (<NUM>) disposed on the opposing surface of the display panel (<NUM>),
wherein the panel bottom sheet (<NUM>-<NUM>) includes:
a first base (<NUM>) having a top surface;
a first light-absorbing layer (<NUM>, <NUM>) disposed on the entire top surface of the first base (<NUM>)
a top bonding layer (<NUM>) disposed between the display panel (<NUM>) and the first light-absorbing layer (<NUM>, <NUM>);
an interlayer bonding layer (<NUM>) disposed below the first base (<NUM>) and the first light-absorbing layer (<NUM>, <NUM>); and
a wiring pattern portion (<NUM>) disposed below the interlayer bonding layer (<NUM>) and including a plurality of wiring patterns (200a),
wherein the first light-absorbing layer (<NUM>, <NUM>) is disposed to completely cover the wiring pattern portion (<NUM>) and includes a black ink.