KR20140074123A

KR20140074123A - transparent flat plate for touch screen panel and touch screen panel thereof

Info

Publication number: KR20140074123A
Application number: KR1020120142349A
Authority: KR
Inventors: 김낙원; 최승규; 곽무선
Original assignee: 엘지디스플레이 주식회사
Priority date: 2012-12-07
Filing date: 2012-12-07
Publication date: 2014-06-17
Also published as: KR102029439B1

Abstract

According to an embodiment of the present invention, there is provided a touch panel including a glass substrate, a transparent touch electrode formed on the glass substrate, and a correction layer formed on the glass substrate to cover the touch electrode, wherein the correction layer is made of acrylic, Discloses a transparent planar body made of a transparent polymer such as acrylic, uretane, polyimide, polycarbonate, siloxane, and metaloxane polymer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a transparent flat plate for a touch screen panel,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent flat member for a touch screen panel having reduced visibility of a touch electrode.

The structure of the touch screen panel for detecting the input position has been variously studied, but the capacitance type is widely used as an example. This electrostatic capacitance type is constituted by a dielectric layer interposed between a pair of transparent flat bodies each having a transparent conductive film having a predetermined pattern shape. When a finger or the like comes into contact with the operation surface, It is possible to detect the touch position.

Such a touch screen panel can be mounted on a surface of a liquid crystal display device, an OLED, or the like, and includes a transparent flat body. However, the touch screen panel up to now has a problem that the pattern shape of the transparent touch electrode formed on the transparent flat member becomes noticeable to the eye.

One way to solve this problem is to form an undercoat layer 30 between the touch electrode 20 and the substrate 10 as illustrated in FIG.

The undercoat layer 30 has a two-layer structure of a high refractive index layer 31 and a low refractive index layer 33. The high refractive index layer 31 has a refractive index of 1.6 to 2.3 and the low refractive layer 33 has a refractive index of 1.4 to 1.6 .

The high refractive index layer 31 is made of a curable organic material such as acryl resin or urethane resin, and the low refractive layer 33 is preferably an inorganic material, especially SiO ₂ . The thicknesses of the high refractive index layer 31 and the low refractive index layer 33 are respectively in the range of 20 to 100 nm and the thickness of the touch electrode 20 is within the range of 20 to 40 nm.

However, when such a method is used for a capacitive transparent touch switch, there is a problem that the pattern shape of the transparent conductive layer becomes conspicuous to the eye.

More specifically, the touch electrode 20 formed by the sputtering method has a different refractive index depending on each wavelength in the visible light region, and the short wavelength side is at least 0.3 higher than the long wavelength. Therefore, there is a problem that the effective wavelength range for correcting the reflectance is narrow with such an undercoat layer 30 only, and the transparent conductive layer is visible.

The reflectance correction by such an undercoat layer has the principle that reflected light at each interface causes destructive interference with each other and attenuates. However, in order to improve the performance of the touch screen panel, when the thickness of the touch electrode 20 is increased (eg, 40 nm to 140 nm), the optical thickness of the transparent conductive film is 1/4, 3/4, / 4, ..., the undercoating structure is not suitable because the reflection interference occurs between the reflected light at the upper and lower surfaces of the touch electrode and the reflectance becomes very high.

In addition, when the touch electrode 20 is stacked on the undercoat layer 30, the step difference of the touch electrode is exposed. However, as the thickness of the touch electrode 20 is increased to improve the performance, the step difference becomes conspicuous. Therefore, the diffused reflection due to the step becomes large, so that the pattern of the touch electrode 20 can not be easily recognized.

Disclosure of Invention Technical Problem [8] The present invention has been made in view of the above background, and it is an object of the present invention to provide a transparent flat panel for a touch screen panel in which a touch electrode pattern is not easily visible.

According to an embodiment of the present invention, there is provided a touch panel including a glass substrate, a touch electrode formed of ITO on the glass substrate, and a correction layer formed on the glass substrate to cover the touch electrode, Discloses a transparent planar body made of a transparent polymer such as acrylic, uretane, polyimide, polycarbonate, siloxane, and metaloxane polymer.

If the thickness of the touch electrode is 30 to 50 nm, the thickness of the correction layer is 30 to 60 nm, and the thickness of the touch electrode is 120 to 170 nm, (nm).

The transparent planar body may further include an overcoat layer that alleviates a level difference over the correction layer, and the thickness of the overcoat layer is preferably 2 (um) or less.

The compensation layer may further comprise a buffer layer made of silicon oxide or silicon nitride.

The correction layer may be formed by any one of spin coating, slit coating, roll coating and ink jet coating.

According to the embodiment of the present invention, the difference in the surface reflectance for the touch electrode and the difference in the surface reflectance of the portion where the touch electrode is absent is reduced, thereby reducing the visibility of the touch electrode while mitigating the step difference of the touch electrode using the correction layer made of transparent polymer .

Further, since the compensating layer relieves the step difference of the touch electrode, it is possible to increase the thickness of the touch electrode, thereby improving the sensitivity of the touch screen panel.

1 is a view for explaining a conventional technique.
2 shows a cross-sectional view of a transparent flat body according to a first embodiment of the present invention.
FIG. 3 shows a transparent flat body according to a second embodiment of the present invention.
4 shows a view of a transparent flat body according to a third embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

2 shows a cross-sectional view of a transparent flat body according to a first embodiment of the present invention.

2, the transparent flat member of the first embodiment includes a substrate 100, a touch electrode 200, and a correction layer 300.

The substrate 100 is composed of a glass substrate.

The touch electrode 200 is a transparent electrode such as ITO or IZO, and is formed on a glass substrate by a sputtering method. The refractive index of the touch electrode 200, especially ITO, is 1.7 to 2.2 depending on the wavelength range. The touch electrode 200 has a thickness of 30 to 50 (nm) or 120 to 170 (nm) because of its excellent light transmittance.

The compensation layer 300 is formed to cover the touch electrode 200 on the substrate 100. Correction layer 300 has a refractive index in the range of 1.5 to 1.9, And a transparent polymer capable of thermosetting. As such a transparent transparent polymer, acryl, urethane, polyimide, polycarbonate, siloxane, and metaloxane polymer may be preferably used, and a photoinitiator may be further added. The correction layer may be patterned by exposure and development only, and may be configured to be cured by light.

Since the metaloxane polymer has a large refractive index scattering (generally, about 0.2 in the range of 380 to 780 nm) in comparison with a general organic film material, the metaloxane polymer has a refractive index different from that of the ITO of the touch electrode 200 It is advantageous for material and index matching.

If the thickness D1 of the touch electrode 200 is 30 to 50 nm, the correction layer 300 is formed to have a thickness D2 of 30 to 60 nm, The correction layer 300 should be formed to have a thickness D2 of 50 to 110 (nm) so that the index matching is satisfactory so that the portion having the touch electrode 200 (hereinafter referred to as a pattern portion) It is possible to reduce the reflectance difference of the wavelength band in the portion where the portion is absent (removal portion), thereby lowering the visibility of the touch electrode 200.

The index matching between the touch electrode 200 and the correction layer 300 is performed under the following conditions. When the average reflectance difference between the pattern portion and the removing portion is 1.5 (%) or less and the relative ratio is within 20%, the difference in reflectance between the pattern portion and the removing portion can be effectively reduced. Here, the relative ratio is defined as "reflectance of pattern portion / reflectance of pattern rejection " x 100 ", and quantifies the range of light reflected from the pattern portion and light reflected from the pattern portion. If the relative ratio exceeds 20 (%), there is a problem that the light reflected from the pattern portion increases and the touch electrode 200 is visible.

Graph 1 below shows the preferred thickness of the compensating layer according to the above conditions when the touch electrode is 30 (nm). The optimal range in the graph is a range that satisfies the above condition.

[Graph 1]

Graph 2 below shows the preferred thickness of the compensating layer according to the above conditions when the touch electrode is 50 (nm).

[Graph 2]

Graph 3 below shows the preferred thickness of the compensating layer according to the above conditions when the touch electrode is 120 (nm).

[Graph 3]

Graph 4 below shows the preferable thickness of the correction layer according to the above conditions when the touch electrode is 170 (nm).

[Graph 4]

It can be seen from the above test results that if the thickness D1 of the touch electrode 200 is 30 to 50 nm, the compensation layer 300 is formed to have a thickness D2 of 30 to 60 (nm) When the compensating layer 300 is formed to have a thickness D2 of 50 to 110 (nm), the reflectance ratio between the pattern portion and the removing portion is most effectively adjusted to the touch electrode 200) can be solved.

If the correction layer 300 is formed of an organic layer as described above, it is possible to alleviate the step difference of the touch electrode 200 and to solve the problem that the touch electrode 200 is recognized due to irregular reflection at the step difference.

The compensation layer thus formed is deposited by spin coating, slit coating, roll coating, ink jet coating, or the like.

In order to alleviate the step difference, the overcoat layer 400 may be further formed on the correction layer 300 as in the second embodiment of FIG. The overcoat layer 400 is a transparent resin and the thickness D3 is not particularly limited. However, it is preferable that the overcoat layer 400 has a thickness of 2 (um) or less in order to minimize adhesion and absorption of transmitted light.

On the other hand, the following graph shows the case where the above-described correction layer 300 is not provided and the case where the correction layer 300 is present, the portion where the touch electrode 200 is formed (the pattern portion) (Removal) of the surface reflectance. The smaller the difference in the surface reflectance between the pattern part and the removal part, the lower the visibility of the touch electrode.

In this experiment, the touch electrode was formed to have a thickness of 140 (nm) ITO, and the correction layer was formed to have a thickness of 80 (nm) of zirconium (Zr) -metalic acid polymer.

[Table 1] (when there is no correction layer)

[Graph 5]

[Table 2] (when there is a correction layer)

[Graph 6]

As can be seen from the above table and graph (reflectance by wavelength band), when there is no compensation layer, the difference in surface reflectance between the pattern portion and the removal portion is observed to be 5.92 (%), As shown in the graph, it can be seen that the correction layer is effective in improving the visibility through the fact that the distribution of the wavelength band in the removal region is close to the pattern region.

4 is a cross-sectional view of a transparent flat member according to a third embodiment of the present invention.

In the third embodiment, the transparent planar body includes the substrate 100, the touch electrode 200, and the correction layer 300 formed thereon. The substrate 100 and the touch electrode 200 are configured in the same manner as in the above-described embodiment, and thus their detailed description is omitted.

In the third embodiment, the correction layer 300 is composed of a two-layer structure of the inorganic film 310 and the organic film 320.

The inorganic film 310 is formed of a silicon oxide film or a silicon nitride film and has a thickness of 10 to 30 (nm). If the thickness of the inorganic film is 10 nm or less, it is difficult to uniformly form the film thickness. If the thickness is 10 nm or more, the reflectance at the short wavelength side is slightly off- Can be increased.

The organic film 320 has a refractive index in the range of 1.5 to 1.9, And a transparent polymer capable of thermosetting. As such a transparent polymer, acrylic, uretane, polyimide, polycarbonate, siloxane, and metaloxane polymer may be used. Of these, siloxane, Or a metalloxane polymer may be preferably used.

Since the metaloxane polymer has a large refractive index scattering (generally in the range of 380 to 780 nm in the range of 380 to 780 nm) compared to a general organic film material, the metaloxane polymer has a refractive index different from that of the ITO It is advantageous to match.

When the thickness of the touch electrode 200 is 30 to 50 nm, the organic film 320 is formed to a thickness of 30 to 60 nm. When the thickness of the touch electrode 200 is 120 to 170 nm , The organic layer 320 should be formed with a thickness of 50 to 110 nm so that the index matching can be performed well and the difference in reflectance between the portions where the touch electrode 200 is present and the portions where the touch electrode 200 is not present can be reduced, .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims

A glass substrate,
A transparent touch electrode formed on the glass substrate,
And a correction layer formed on the glass substrate to cover the touch electrode,
The correction layer may be a transparent layer made of a transparent polymer such as acrylic, urethane, acrylic, urethane, polyimide, polycarbonate, siloxane, or a metalloxane polymer. Flat body.

The method according to claim 1,
If the thickness of the touch electrode is 30 to 50 nm, the thickness of the correction layer is 30 to 60 nm, and the thickness of the touch electrode is 120 to 170 nm, (nm).

The method according to claim 1,
And an overcoat layer for relieving a level difference over the correction layer is further formed.

The method of claim 3,
Wherein the thickness of the overcoat layer is 2 (um) or less.

The method according to claim 1,
Wherein the compensation layer further comprises a buffer layer comprised of silicon oxide or silicon nitride.

The method according to claim 1,
The correction layer is a transparent flat layer formed by any one of a spin coating method, a slit coating method, a roll coating method and an ink jet coating method.

A touch screen panel comprising a transparent flat body according to any one of claims 1 to 6.