KR20220135872A - Digitizer and image display device including the same - Google Patents

Abstract

A digitizer comprises: a base layer; a lower part conductive line disposed on an upper surface of the base layer; a buffer layer formed on the upper surface of the base layer and having a thickness smaller than that of the lower part conductive line; an interlayer insulating layer formed on the buffer layer and covering the lower part conductive line; and an upper part conductive line disposed on the interlayer insulating layer and the buffer layer and electrically connected to the lower part conductive line. A bending reliability of the upper part conductive line may be improved through the buffer layer. Therefore, the present invention is capable of providing the digitizer having electrical reliability.

Description

Digitizer and image display device including same

The present invention relates to a digitizer and an image display device including the same. More particularly, it relates to a digitizer including a multilayer conductive structure and an image display device including the same.

Recently, various sensing functions and communication functions are combined in an image display device, and are implemented in the form of, for example, a smartphone. For example, electronic devices in which a touch panel or a touch sensor is attached to a display panel of the image display device to select a menu displayed on a window surface to implement an information input function are being developed.

In addition, as disclosed in Korean Patent No. 10-1750564, a digitizer that converts analog coordinate information into a digital signal by an electromagnetic method is disposed on the back side of the image display device.

Recently, a flexible display having flexibility that can be folded or bent is being developed, and accordingly, a sensor structure such as the digitizer needs to be developed to have appropriate physical properties, design, and structure so that it can also be applied to the flexible display.

For example, in the case of a digitizer applied to a thin display device, a wire crack or wire peeling may easily occur in a folding part. In this case, resistance may be increased by damaged wiring. Therefore, there is a need to develop a digitizer capable of maintaining reliability even when bending/folding is repeated.

Korean Patent Publication No. 10-1750564

One object of the present invention is to provide a digitizer having improved mechanical and electrical reliability.

An object of the present invention is to provide an image display device including a digitizer having improved mechanical and electrical reliability.

1. base layer; a lower conductive line disposed on the upper surface of the base layer; a buffer layer formed on the upper surface of the base layer and having a thickness smaller than that of the lower conductive line; an interlayer insulating layer formed on the buffer layer and covering the lower conductive line; and an upper conductive line disposed on the interlayer insulating layer and the buffer layer and electrically connected to the lower conductive line.

2. The digitizer according to the above 1, wherein the lower conductive line protrudes from the upper surface of the buffer layer.

3. The digitizer according to 1 above, wherein the upper conductive line is in contact with a top surface of the buffer layer.

4. The digitizer according to the above 1, wherein the surface roughness of the buffer layer is smaller than the surface roughness of the base layer.

5. The digitizer according to 1 above, wherein a thickness of the lower conductive line is greater than a thickness of the upper conductive line.

6. The digitizer according to the above 1, wherein the base layer includes a folding part.

7. The digitizer according to the above 6, further comprising an opening through which the interlayer insulating layer is removed from the folding part to expose an upper surface of the buffer layer.

8. The digitizer according to the above 7, wherein the upper conductive line in the opening is in contact with the upper surface of the buffer layer.

9. The digitizer according to the above 6, wherein the upper conductive line intersects the folding axis of the folding part, and the lower conductive line is parallel to the folding axis of the folding part.

10. The digitizer of 1 above, wherein the lower conductive line includes a plurality of lower conductive lines, and the interlayer insulating layer includes line patterns covering each of the lower conductive lines.

11. The digitizer according to the above 10, wherein the upper conductive line is in contact with the upper surface of the buffer layer between the line patterns adjacent to the interlayer insulating layer.

12. The method of 1 above, wherein the lower conductive line includes a plurality of first lower conductive lines and a plurality of second lower conductive lines extending in a second direction parallel to the upper surface of the base layer,

The upper conductive line is parallel to the upper surface of the base layer and includes a plurality of first upper conductive lines and a plurality of second upper conductive lines extending in a first direction perpendicular to the second direction.

13. The method of 12 above, further comprising: first contacts electrically connecting the first upper conductive lines and the second lower conductive lines to form a first conductive coil; and

and second contacts electrically connecting the first lower conductive lines and the second upper conductive lines to form a second conductive coil.

14. The method of 13 above, wherein the first conductive coil extends in the first direction, and a plurality of the first conductive coils are arranged along the second direction,

The second conductive coil extends in the second direction, and a plurality of the second conductive coils are arranged along the first direction.

15. Display panel; and a digitizer according to the above-described embodiments disposed under the display panel.

16. The image display device according to 15 above, further comprising a touch sensor disposed on the display panel.

17. The image display according to 16 above, further comprising a rear cover and a window substrate, wherein the touch sensor is disposed between the window substrate and the display panel, and the digitizer is disposed between the display panel and the rear cover. Device.

According to embodiments of the present invention, the buffer layer may be formed on the base layer, and the interlayer insulating layer for insulating the lower conductive line and the upper conductive line may be at least partially removed from the folding part of the digitizer. Accordingly, the upper conductive line may be in contact with the buffer layer having improved adhesion properties than the base layer.

Accordingly, it is possible to reduce or suppress delamination and folding cracks of the upper conductive line occurring in the folding part. In addition, since the folding thickness of the folding part is reduced, flexibility and folding reliability may be further improved.

In example embodiments, the upper conductive line may intersect a folding axis, and the lower conductive line may be parallel to the folding axis. By forming the thickness of the upper conductive line smaller than the thickness of the lower conductive line It is possible to suppress electrode cracks and improve folding characteristics.

The digitizer may include a plurality of first conductive coils and second conductive coils, and the first conductive coil and the second conductive coil may include a plurality of conductive loops. Accordingly, a digitizer that promotes the electromagnetic induction phenomenon and has high resolution and improved flexible characteristics can be provided.

1 and 2 are schematic cross-sectional views illustrating a digitizer according to exemplary embodiments.
3 and 4 are schematic plan views illustrating conductive coils included in a digitizer according to example embodiments.
5 is a schematic plan view illustrating a digitizer according to exemplary embodiments.
6 is a schematic cross-sectional view illustrating a digitizer according to some exemplary embodiments.
7 is a schematic cross-sectional view illustrating an image display apparatus according to example embodiments.

SUMMARY Embodiments of the present invention provide a digitizer including conductive patterns having a multilayer structure and having improved folding reliability. In addition, there is provided an image display device including the digitizer.

Hereinafter, with reference to the drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical spirit of the present invention together with the above-described content of the present invention, so the present invention is described in such drawings It should not be construed as being limited only to the matters.

In the drawings below, two directions parallel to and intersecting with the upper surface of the digitizer 100 or the base layer 105 are defined as a first direction and a second direction. For example, the first direction and the second direction may cross each other perpendicularly.

The first direction may correspond to a width direction, a row direction, or an X-direction of the digitizer 100 . The second direction may correspond to a longitudinal direction, a column direction, or a Y-direction of the digitizer 100 .

The terms "row direction", "column direction", etc. used in the present application do not refer to absolute directions, and should be understood as relative meanings designating different directions.

1 and 2 are schematic cross-sectional views illustrating a digitizer according to exemplary embodiments. For example, FIG. 1 is a cross-sectional view taken along the line I-I' of FIG. 3 in the thickness direction. FIG. 2 is a cross-sectional view taken along line II-II' of FIG. 3 .

1 and 2 , a digitizer according to example embodiments may include a lower conductive layer 110 and an upper conductive layer 130 formed on a base layer 105 . The lower conductive layer 110 and the upper conductive layer 130 may be separated from each other with the interlayer insulating layer 125 interposed therebetween.

The lower conductive layer 110 may include a first lower conductive line 112 (see FIG. 4 ) and a second lower conductive line 114 (see FIG. 3 ). The upper conductive layer 130 may include a first upper conductive line 132 (see FIG. 3 ) and a second upper conductive line 134 (see FIG. 4 ).

The substrate layer 105 is used to encompass a substrate or a film type substrate for forming the conductive layers 110 and 130 and the interlayer insulating layer 125 . For example, the base layer 105 may include a polymer applicable to a flexible display. Examples of the polymer include cyclic olefin polymer (COP), polyethylene terephthalate (PET), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), poly Allylate (polyallylate), polyimide (PI), cellulose acetate propionate (CAP), polyethersulfone (PES), cellulose triacetate (TAC), polycarbonate (PC), cyclic olefin copolymer (COC), poly Methyl methacrylate (PMMA), etc. are mentioned.

Preferably, the base layer 105 may include polyimide to secure stable folding characteristics. The thickness of the base layer 105 may be about 10 to 50 μm, preferably about 20 to 30 μm in consideration of the stable support of the conductive line of the multilayer structure.

The lower conductive layer 110 and the upper conductive layer 130 may each include a low-resistance metal. For example, the lower conductive layer 110 and the upper conductive layer 130 are silver (Ag), gold (Au), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium ( Cr), titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc ( Zn), tin (Sn), molybdenum (Mo), calcium (Ca), or an alloy containing at least two of them.

Preferably, the lower conductive layer 110 and the upper conductive layer 130 may include copper or a copper alloy to realize low resistance.

According to exemplary embodiments, the buffer layer 120 may be formed on the upper surface of the base layer 105 . The buffer layer 120 may be in integrated contact with the upper surface of the base layer 105 .

The thickness of the buffer layer 120 may be smaller than the thickness of the lower conductive layer 110 . Accordingly, the lower conductive layer 110 or the lower conductive lines 112 and 114 may protrude from the upper surface of the buffer layer 120 .

The thickness of the buffer layer 120 may be smaller than the thickness of the base layer 105 . In some embodiments, the thickness of the buffer layer 120 may be about 1 to 5 μm, preferably about 1 to 3 μm, and more preferably about 1 to 2 μm.

The buffer layer 120 may include an organic insulating material such as an epoxy-based resin, an acrylic resin, a siloxane-based resin, or a polyimide-based resin, or an inorganic insulating material such as silicon oxide or silicon nitride. Preferably, the buffer layer 120 may be formed using an organic insulating material to improve flexible properties.

The interlayer insulating layer 125 may be formed on the buffer layer 120 to cover the lower conductive layer 110 . The interlayer insulating layer 125 may include an organic insulating material such as an epoxy-based resin, an acrylic resin, a siloxane-based resin, or a polyimide-based resin, or an inorganic insulating material such as silicon oxide or silicon nitride. Preferably, the interlayer insulating layer 125 may be formed using an organic insulating material to improve flexible properties.

As described above, the buffer layer 120 may be formed on the base layer 105 before the interlayer insulating layer 125 is formed. Accordingly, the formation height or thickness of the interlayer insulating layer 125 may be reduced. Accordingly, even when the thickness of the lower conductive layer 110 is increased, an insulating structure having a sufficient thickness for forming the contacts 135 and 137 (refer to FIGS. 3 and 4 ) can be easily formed.

The upper conductive layer 130 may be formed on the interlayer insulating layer 125 . In some embodiments, the passivation layer 140 may be formed on the interlayer insulating layer 125 to cover the upper conductive layer 130 . The passivation layer 140 may include an organic insulating material such as an epoxy-based resin, an acrylic resin, a siloxane-based resin, or a polyimide-based resin, or an inorganic insulating material such as silicon oxide or silicon nitride. Preferably, the passivation layer 140 may be formed using an organic insulating material to improve flexible properties.

Each of the interlayer insulating layer 125 and the passivation layer 140 may have a thickness in the range of about 1.5 to 20 μm to improve folding characteristics.

In some embodiments, the thickness of the interlayer insulating layer 125 may be greater than the thickness of the buffer layer 120 .

As shown in FIG. 2 , the base layer 105 or the digitizer 100 may include a folding part FA, and the digitizer 100 may be bent or folded through the folding part FA.

In example embodiments, the interlayer insulating layer 125 may be at least partially removed from the folding part FA. In some embodiments, the folding part FA may be defined by a region from which the interlayer insulating layer 125 is removed.

For example, the opening 145 may be formed in the folding part FA by removing the insulating interlayer 125 . In example embodiments, the upper surface of the buffer layer 120 may be exposed through the opening 145 .

For example, the opening 145 may be defined by opposing sidewalls of the interlayer insulating layer 125 and a top surface of the buffer layer 120 .

The upper conductive layer 130 (eg, the first upper conductive line 132 ) is in contact with the upper surface of the interlayer insulating layer 125 and the upper surface of the buffer layer 120 exposed by the opening 145 , and the first direction can be extended. The passivation layer 140 may also conformally extend on the folding part FA and cover the upper conductive layer 130 .

As described above, as the interlayer insulating layer 125 is removed from the folding part FA, the thickness of the digitizer 100 in the folding part FA may be reduced. Accordingly, the elongation in the folding part FA is increased to secure improved bending characteristics and flexibility.

Accordingly, it is possible to prevent cracks or breakage of the upper conductive layer 130 due to stress propagation occurring in the folding part FA.

In an area other than the folding part FA, the interlayer insulating layer 125 having a sufficient thickness may be formed. In addition, the buffer layer 120 may be added to form a multi-layered insulating structure. Accordingly, it is possible to sufficiently cover the lower conductive layer 110 having a relatively large thickness and low resistance.

In the folding part FA, the interlayer insulating layer 125 may be removed to prevent lifting and peeling of the upper conductive layer 130 occurring during folding. Since the upper conductive layer 130 extends along the surface of the opening 145 , a contact area of the upper conductive layer 130 may be increased. Accordingly, the adhesion of the upper conductive layer 130 may be additionally increased.

According to exemplary embodiments, the buffer layer 120 is formed on the base layer 105 , and thus the upper conductive layer 130 may contact the buffer layer 120 and not directly contact the base layer 105 . have.

The base layer 105 and the lower conductive layer 110 may be manufactured from a copper clad laminate (CCL). For example, the substrate layer 105 included in the copper clad laminate may be a surface roughened substrate (eg, roughened polyimide substrate) for stable bonding of the lower conductive layer 110 . The lower conductive layer 110 may be formed by patterning the copper foil included in the copper-clad laminate. Accordingly, the surface roughness of the base layer 105 may be additionally increased by the etching process for forming the lower conductive line.

Therefore, when the relatively thin upper conductive layer 130 is in direct contact with the substrate layer 105, it may be mechanically damaged by the surface roughness of the substrate layer 105, and peeling may be caused when a folding stress is applied. can

However, according to exemplary embodiments, since the buffer layer 120 is first formed before the interlayer insulating layer 125 is formed, the base layer 105 may be substantially planarized to reduce the illuminance. In addition, the adhesion of the upper conductive layer 130 may be further improved by using an organic insulating material having excellent adhesion to the metal.

3 and 4 are schematic plan views illustrating conductive coils included in a digitizer according to example embodiments.

3 and 4 , the digitizer 100 according to example embodiments may include a first conductive coil 50 and a second conductive coil 70 .

The first conductive coil 50 and the second conductive coil 70 may be defined by combining the lower conductive layer 110 and the upper conductive layer 130 by the contacts 135 and 137 .

The lower conductive layer 110 may include a first lower conductive line 112 (see FIG. 4 ) and a second lower conductive line 114 (see FIG. 3 ). For example, the second lower conductive line 114 may be shorter than the first lower conductive line 112 .

The upper conductive layer 130 may include a first upper conductive line 132 (see FIG. 3 ) and a second upper conductive line 134 (see FIG. 4 ). For example, the second upper conductive line 134 may be shorter than the first upper conductive line 132 .

The first lower conductive line 112 and the second lower conductive line 114 may extend in the second direction. The first upper conductive line 132 and the second upper conductive line 134 may extend in a first direction.

As shown in FIG. 3 , the first upper conductive line 132 of the upper conductive layer 130 and the second lower conductive line 114 of the lower conductive layer 110 are coupled to each other to form a first conductive coil 50 . can form.

The first upper conductive line 132 and the second lower conductive line 114 may together form a first conductive coil 50 to serve as a sensing line for an input pen through electromagnetic induction.

For example, the first upper conductive line 132 and the second lower conductive line 114 may be electrically connected to each other through the first contact 135 . A plurality of first upper conductive lines 132 and a plurality of second lower conductive lines 114 are electrically connected to each other through a plurality of first contacts 135 to form a single first conductive coil 50 . A plurality of conductive loops may be included. For example, four first conductive loops may be included in one first conductive coil 50 .

In some embodiments, the first conductive loops may have different sizes or areas in a planar direction. The first contact 135 may be formed substantially integrally with the first upper conductive line 132 through the interlayer insulating layer 125 .

A first input line 113 and a first output line 115 may be connected to any one of the first conductive loops. For example, the first input line 113 may be connected to an innermost first conductive loop among the first conductive loops. The first output line 115 may be connected to an outermost first conductive loop among the first conductive loops.

The current input from the first input line 113 may alternately cycle through the lower conductive layer 110 and the upper conductive layer 130 through the first conductive loops, and may be discharged through the first output line 115 . have.

In some embodiments, the first input line 113 and the first output line 115 may be included in the lower conductive layer 110 .

In some embodiments, the lower conductive layer 110 may include a first internal connection line 114a. For example, adjacent first conductive loops may be connected by a first internal connection line 114a.

As shown in FIG. 4 , the first lower conductive line 112 of the lower conductive layer 110 and the second upper conductive line 134 of the upper conductive layer 130 are coupled to each other to form a second conductive coil 70 . can form.

The first lower conductive line 112 and the second upper conductive line 134 may be provided together as a sensing line for an input pen through electromagnetic induction by forming a second conductive coil 70 together.

For example, the first lower conductive line 112 and the second upper conductive line 134 may be electrically connected to each other through the second contact 137 . A plurality of first lower conductive lines 112 and a plurality of second upper conductive lines 134 are electrically connected to each other through a plurality of second contacts 137 to form a single second conductive coil 70 . A plurality of conductive loops may be included. For example, four second conductive loops may be included in one second conductive coil 70 .

In some embodiments, the second conductive loops may have different sizes or areas in a planar direction. The second contact 137 may be formed substantially integrally with the second upper conductive line 134 through the interlayer insulating layer 120 .

A second input line 117 and a second output line 119 may be connected to any one of the second conductive loops. For example, the second input line 117 may be connected to an innermost second conductive loop among the second conductive loops. The second output line 119 may be connected to an outermost second conductive loop among the second conductive loops.

The current input from the second input line 117 may alternately cycle through the lower conductive layer 110 and the upper conductive layer 130 through the second conductive loops, and may be discharged through the second output line 119 . have.

In some embodiments, the second input line 117 and the second output line 119 may be included in the lower conductive layer 110 .

In some embodiments, the upper conductive layer 130 may further include an external connection line 134a. For example, the second input line 117 and the second output line 119 may be connected through the second conductive loop and the second contact 137 by the external connection line 134a.

In an embodiment, the external connection line 134a may be connected to two different second conductive coils. For example, the output line 119 connected to one of the second conductive coils 70 may be connected to the input line 117 of the other second conductive coil 70 through an external connection line 134a.

In some embodiments, the upper conductive layer 130 may further include a second internal connection line 134b. For example, adjacent second conductive loops in the second conductive coil 70 may be connected to each other by the second internal connection line 134b.

3 and 4 show that four conductive loops are included in one conductive coil, but the number of conductive loops in the conductive coil may be adjusted in consideration of the size and resolution of the image display device.

As described with reference to FIGS. 3 and 4 , the first conductive coil 50 and the second conductive coil 70 may each include a plurality of conductive loops having different sizes.

Accordingly, it is possible to sufficiently increase the magnetic field strength generated by the digitizer 100 , so that, for example, energy transfer to the input pen in contact with the window surface of the image display apparatus can be efficiently enhanced.

In addition, since the conductive loop is formed by connecting the lower conductive layer 110 and the upper conductive layer 130 through the contacts 135 and 137 , the number of loops of the conductive coil in a limited space is efficiently increased and electromagnetic induction efficiency is achieved. can improve

In example embodiments, both the lower conductive layer 110 and the upper conductive layer 130 may be disposed on the upper surface of the base layer 105 . Accordingly, when bending or folding through the base layer 105 , the stress direction for the lower conductive layer 110 and the upper conductive layer 130 may be adjusted in the same manner.

For example, when tensile stress is applied to the bottom surface of the base layer 105 , compressive stress may be applied to the lower conductive layer 110 and the upper conductive layer 130 . Accordingly, a neutral plane in which stress is canceled may be easily generated to be adjacent to the conductive layers 110 and 130 . Accordingly, stress applied to the conductive layers 110 and 130 may be relieved, thereby reducing or preventing electrode cracking due to folding.

In example embodiments, the thickness of the lower conductive layer 110 may be greater than the thickness of the upper conductive layer 130 . For example, the thickness of the first lower conductive line 112 may be greater than the thickness of the first upper conductive line 132 .

As will be described later with reference to FIG. 5 , the first upper conductive line 132 may extend in a first direction (eg, a row direction or a width direction) and intersect the folding axis. For example, the first upper conductive line 132 may be perpendicular to the folding axis. The first lower conductive line 112 may extend in a second direction (a column direction or a length direction) and may be substantially parallel to the folding axis.

In some embodiments, by reducing the thickness of the first upper conductive line 132 through which the folding stress is easily transmitted as it intersects the folding axis, prevention of cracks in the conductive line may be reduced or suppressed. Also, as described with reference to FIG. 2 , the interlayer insulating layer 125 may be removed from the folding part FA. Accordingly, it is possible to further reduce folding stress and more effectively suppress peeling and cracking of the first upper conductive line 132 .

The first lower conductive line 112 that is parallel to the folding axis and is relatively free from folding stress is formed to have a large thickness, so that a sufficient electromagnetic induction effect can be realized by expanding a current path through the conductive coil.

In an embodiment, the second lower conductive line 114 may also have a greater thickness than the second upper conductive line 134 .

In some embodiments, the thickness of the lower conductive layer 110 (the first lower conductive line or the second lower conductive line) may be about 5 to 20 μm, preferably 10 to 20 μm. The thickness of the upper conductive layer 130 (the first upper conductive line or the second upper conductive line) may be 6 μm or less, preferably about 1 to 6 μm.

5 is a schematic plan view illustrating a digitizer according to exemplary embodiments.

Referring to FIG. 5 , a plurality of first conductive coils 50 and second conductive coils 70 may be arranged on the upper surface of the base layer 105 .

The first conductive coil 50 may extend in the first direction or the row direction. The plurality of first conductive coils 50 may be arranged along the second direction or the column direction.

For example, n first conductive coils 50 - 1 to 50 - n may be sequentially arranged along the second direction (n is a natural number).

The second conductive coil 70 may extend in the second direction or the column direction. The plurality of second conductive coils 70 may be arranged along the first direction or the row direction.

For example, m second conductive coils 70 - 1 to 70 - m may be sequentially arranged in the first direction.

An area in which the first and second conductive coils 50 and 70 overlap and are arranged may be provided as an active area AA in which sensing by electromagnetic induction is performed.

For example, the central portion of the base layer 105 may include a folding portion FA. A folding shaft 80 extending in the second direction may be positioned in the folding part FA. The digitizer 100 according to example embodiments may be bent or folded around the folding axis 80 .

In some embodiments, the thickness of the first upper conductive line 132 or the second upper conductive line 134 crossing the folding axis 80 may be relatively small. Accordingly, it is possible to prevent cracking of the upper conductive layer 130 to which the folding stress is directly applied and to increase flexibility. In addition, as described with reference to FIG. 2 , the interlayer insulating layer 125 is at least partially removed from the folding part FA, so that peeling of the upper conductive layer 130 can be suppressed even when abruptly folded or folded.

As described above, in the folding part FA, the first upper conductive line 132 may contact the buffer layer 120 with improved adhesion. Accordingly, peeling and cracking of the first upper conductive line 132 may be suppressed even when repeatedly folded or folded.

The thicknesses of the first lower conductive line 112 and the second lower conductive line 114 that are parallel to the folding axis 80 and have relatively small folding stress are increased to reduce resistance and improve the efficiency of generating a magnetic field through the conductive coil. can do it

6 is a schematic cross-sectional view illustrating a digitizer according to some exemplary embodiments.

Referring to FIG. 6 , as described above, the lower conductive layer 110 including the base layer 105 and the first lower conductive line 112 may be formed from the copper clad laminate. For example, the lower conductive lines 112 and 114 may be formed by etching the copper foil included in the copper foil laminate. The surface roughness of the upper surface of the base layer 105 may be increased by the etching process.

Thereafter, the buffer layer 120 may be formed on the upper surface of the base layer 105 . The buffer layer 120 may be formed by applying a composition including an organic insulating material through a spin coating process so as not to cover the upper surface of the lower conductive layer 110 and then thermally curing the composition.

For example, in the spin coating process, the rotation speed may be about 300 to 600 rpm, and the thermal curing temperature may be 100 to 200 °C.

The surface roughness of the buffer layer 120 may be smaller than the surface roughness of the base layer 105 . Accordingly, the upper surface of the base layer 105 may be substantially planarized through the buffer layer 120 .

After the buffer layer 120 is formed, an interlayer insulating layer 125 may be formed to cover the lower conductive layer 110 . In some embodiments, the interlayer insulating layer 125 may be formed in a line pattern covering each of the lower conductive lines 112 and 114 .

In this case, the upper surface of the buffer layer 120 may be exposed between the interlayer insulating layers 125 adjacent in the first direction.

The upper conductive layer 130 or the first upper conductive line 132 may be formed on the buffer layer 120 and the interlayer insulating layer 125 . The upper conductive layer 130 or the first upper conductive line 132 may fill a space between the adjacent interlayer insulating layers 125 having a line pattern shape and may contact the upper surface of the buffer layer 120 .

7 is a schematic cross-sectional view illustrating an image display apparatus according to example embodiments.

Referring to FIG. 7 , the image display apparatus may include the display panel 360 , the touch sensor 200 , and the digitizer 100 according to the above-described exemplary embodiments.

The digitizer 100 may be disposed under the display panel 360 . For example, the digitizer 100 may be disposed between the display panel 360 and the rear cover 380 .

The digitizer 100 includes relatively thick conductive lines for efficiency in generating a magnetic field using electromagnetic induction, and may include a plurality of conductive coils. Accordingly, the digitizer 100 may be disposed under the display panel 360 so as not to be recognized by a user of the image display apparatus.

As described above, by using the structure of the digitizer 100 according to the exemplary embodiments to sufficiently increase the magnetic field strength, for example, energy transfer to the input pen in contact with the window substrate 230 of the image display device can be efficiently performed. can be promoted to

The display panel 360 may include a pixel electrode 310 , a pixel defining layer 320 , a display layer 330 , a counter electrode 340 , and an encapsulation layer 350 disposed on the panel substrate 300 . can

A pixel circuit including a thin film transistor (TFT) may be formed on the panel substrate 300 , and an insulating layer covering the pixel circuit may be formed. The pixel electrode 310 may be electrically connected to, for example, a drain electrode of a TFT on the insulating layer.

The pixel defining layer 320 may be formed on the insulating layer to expose the pixel electrode 310 to define a pixel area. A display layer 330 is formed on the pixel electrode 310 , and the display layer 330 may include, for example, a liquid crystal layer or an organic light emitting layer.

A counter electrode 340 may be disposed on the pixel defining layer 320 and the display layer 330 . The opposing electrode 340 may be provided as a common electrode or a cathode of the image display device, for example. An encapsulation layer 350 for protecting the display panel 360 may be stacked on the opposite electrode 340 .

The touch sensor 200 may be stacked on the display panel 360 and disposed toward the window substrate 230 . The touch sensor 200 may generate capacitance by a user's touch input through the surface of the window substrate 230 . Accordingly, the touch sensor 200 may include a sensing electrode or sensing channels having a thickness smaller than that of the conductive layer included in the digitizer 100 so as not to be recognized by the user. For example, the thickness of the sensing electrode or the sensing channel may be less than 1 μm or less than 0.5 μm.

Each of the sensing electrodes or the sensing channels may be independently disposed in one single layer to interact with an adjacent sensing electrode or sensing channel to generate capacitance.

The touch sensor 200 may be coupled to the display panel 360 through the adhesive layer 260 .

The window substrate 230 includes, for example, a hard coating film and thin glass, and in an embodiment, a light blocking pattern 235 may be formed on a periphery of one surface of the window substrate 230 . The light blocking pattern 235 may include, for example, a color printing pattern. A bezel part or a non-display area of the image display device may be defined by the light blocking pattern 235 .

A polarization layer 210 may be disposed between the window substrate 230 and the touch sensor 200 . The polarizing layer 210 may include a coated polarizer or a polarizing plate.

The polarization layer 210 may be directly bonded to the one surface of the window substrate 230 or may be attached through the first adhesive layer 220 . The touch sensor 200 may be coupled to the polarization layer 210 through the second adhesive layer 225 .

As shown in FIG. 7 , the window substrate 230 , the polarization layer 210 , and the touch sensor 200 may be sequentially disposed from the user's viewing side. In this case, since the sensing electrodes of the touch sensor 200 are disposed under the polarization layer 210 , it is possible to more effectively prevent the sensing electrode from being viewed.

In an embodiment, the touch sensor 200 may be directly transferred onto the window substrate 230 or the polarization layer 210 . In an embodiment, the window substrate 230 , the touch sensor 200 , and the polarization layer 210 may be disposed in the order from the user's viewing side.

Hereinafter, preferred embodiments are presented to help the understanding of the present invention, but these examples are merely illustrative of the present invention and do not limit the appended claims, and are within the scope and spirit of the present invention. It is obvious to those skilled in the art that various changes and modifications are possible, and it is natural that such variations and modifications fall within the scope of the appended claims.

Example

A digitizer having the structure shown in FIG. 6 was formed. Specifically, a buffer layer having a thickness of 1.6 µm was formed on a copper clad laminate on which a Cu lower conductive line having a thickness of 12 µm was formed on a polyimide substrate having a thickness of 10 µm.

Specifically, the acrylic organic photosensitive composition was spin-coated on the base layer at a rotation speed of 500 rpm, and then heat-treated at 150° C. for 24 minutes to form a buffer layer.

Thereafter, using the same organic composition as the buffer layer, interlayer insulating layers covering the lower conductive lines, respectively, were formed. An upper conductive line extending perpendicular to the lower conductive line and having a thickness of 5 μm was formed on the interlayer insulating layer and the buffer layer.

comparative example

A digitizer was formed in the same manner as in Example except that the buffer layer was omitted.

Flexural evaluation/adhesion evaluation

Using the bending evaluation jig of the digitizer of Examples and Comparative Examples, the bending test of the curvature 1R was performed 5000 times and 10,000 times, and whether the upper conductive line was lifted or cracked was observed. In case of lifting or cracking, it was indicated in Table 1 as NG, if not, as OK.

On the other hand, adhesion force measurement was measured using a cross cut test to the buffer layer or the base layer of the upper conductive line.

Specifically, the pressure-sensitive tape was pressed on the upper conductive line by using the cross hatch cut method, and the adhesive strength rating was checked from 0B to 5B depending on the point where it came off.

The measurement results are shown in Table 1 below.

flexion evaluation adhesion 5000 times 10,000 times Example OK OK 4B comparative example NG - 2B

Referring to Table 2, in the embodiment in which the buffer layer was formed, the adhesion of the upper conductive line was increased, and no lifting or peeling occurred even when bending was applied 10,000 times.

50: first conductive coil 70: second conductive coil
100: digitizer 105: base layer
110: lower conductive layer 112: first lower conductive line
114: second lower conductive line 120: buffer layer
125: interlayer insulating layer 130: second conductive layer
132: first upper conductive line 134: second upper conductive line
135: first contact 137: second contact
140: passivation layer 145: opening

Claims (17)

base layer;
a lower conductive line disposed on the upper surface of the base layer;
a buffer layer formed on the upper surface of the base layer and having a thickness smaller than that of the lower conductive line;
an interlayer insulating layer formed on the buffer layer and covering the lower conductive line; and
and an upper conductive line disposed on the interlayer insulating layer and the buffer layer and electrically connected to the lower conductive line. The digitizer according to claim 1, wherein the lower conductive line protrudes from an upper surface of the buffer layer. The digitizer of claim 1 , wherein the upper conductive line is in contact with a top surface of the buffer layer. The digitizer according to claim 1, wherein the surface roughness of the buffer layer is smaller than the surface roughness of the base layer. The digitizer of claim 1 , wherein a thickness of the lower conductive line is greater than a thickness of the upper conductive line. The digitizer of claim 1, wherein the base layer includes a folding part. The digitizer of claim 6 , further comprising an opening through which the interlayer insulating layer is removed from the folding part to expose a top surface of the buffer layer. The digitizer of claim 7, wherein the upper conductive line in the opening is in contact with the upper surface of the buffer layer. The digitizer according to claim 6, wherein the upper conductive line intersects a folding axis of the folding part, and the lower conductive line is parallel to the folding axis of the folding part. The method according to claim 1, wherein the lower conductive line comprises a plurality of lower conductive lines,
The interlayer insulating layer includes line patterns covering each of the lower conductive lines. The digitizer of claim 10 , wherein the upper conductive line is in contact with an upper surface of the buffer layer between the line patterns adjacent to the interlayer insulating layer. The method according to claim 1, wherein the lower conductive line comprises a plurality of first lower conductive lines and a plurality of second lower conductive lines extending in a second direction parallel to the upper surface of the base layer,
The upper conductive line is parallel to the upper surface of the base layer and includes a plurality of first upper conductive lines and a plurality of second upper conductive lines extending in a first direction perpendicular to the second direction. The apparatus of claim 12 , further comprising: first contacts electrically connecting the first upper conductive lines and the second lower conductive lines to form a first conductive coil; and
and second contacts electrically connecting the first lower conductive lines and the second upper conductive lines to form a second conductive coil. The method according to claim 13, wherein the first conductive coil extends in the first direction, a plurality of the first conductive coils are arranged along the second direction,
The second conductive coil extends in the second direction, and a plurality of the second conductive coils are arranged along the first direction. display panel; and
An image display device comprising the digitizer according to claim 1 disposed below the display panel. The image display device of claim 15 , further comprising a touch sensor disposed on the display panel. The method according to claim 16, further comprising a rear cover and a window substrate,
The touch sensor is disposed between the window substrate and the display panel, and the digitizer is disposed between the display panel and the rear cover.

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