Patent Application
20130157022
This application claims the priority of Korean Patent Application No. 10-2011-0136355 filed on Dec. 16, 2011 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a transparent panel in which a transparent electrode is formed on a surface of a transparent substrate without a step, to minimize a pattern exposure phenomenon and simplify the manufacturing process thereof, and a method of manufacturing the transparent panel.
2. Description of the Related Art
A transparent panel is a device manufactured by forming an electrode having a predetermined pattern using a transparent conductive material having excellent light transmittance on a transparent substrate having excellent light transmittance. The transparent panel is widely used in flat panel displays (FPDs) such as a liquid crystal display (LCD) or an organic light emitting display (OLED) or an input device such as a touch screen. In particular, flat panel displays are currently provided as televisions for the home, and users of devices such as smartphones and navigation devices including a touch screen as an input device are increasing, such that demand for transparent panels is also increasing.
Methods of sensing a touch screen contact applied to electronic devices may be classified as a resistive method and a capacitive method. The capacitive method allows for a relatively long lifespan, and various types of intuitive input methods, and ease of movements during touch contact, and thus is increasingly being applied to electronic devices. In particular, as compared to the resistive method, it is easy to implement a multi-touch interface in the capacitive method, and thus it is being widely used in devices such as smartphones.
Touch screens using both the resistive method and the capacitive method include a transparent substrate and a transparent electrode formed on a surface of the transparent substrate. The transparent electrode may be formed by depositing a transparent conductive material such as indium-tin oxide (ITO), zinc oxide (ZnO), or indium-zinc oxide (IZO) on the surface of the transparent substrate using a sputtering method or the like, and etching the deposited transparent conductive material to have a desired pattern. However, in this case, there are provided an area in which the transparent conductive material is formed and an area in which the transparent conductive material is removed on the surface of the transparent substrate, and thus, a pattern exposure phenomenon may be generated due to a difference in light transmittance and refractive indices between the transparent electrode and the transparent substrate.
An aspect of the present invention provides a transparent panel in which a transparent electrode is formed without a step by forming a graphene oxide layer on a transparent substrate, forming an etching resist on a first area which is at least a portion of the graphene oxide layer, and then reducing a second area, apart from the first area, such that the second area may obtain electrical conductivity. Thus, a pattern exposure phenomenon may be minimized, and the manufacturing process of the transparent panel may be simplified.
According to an aspect of the present invention, there is provided a transparent panel, including: a transparent substrate; and a transparent electrode layer formed on the transparent substrate, wherein the transparent electrode layer includes a first area having non-electrical conductivity and a second area having electrical conductivity, and the first area includes a graphene oxide, and the second area includes a reduced graphene oxide.
The transparent electrode may have the same thickness in the first area and the second area.
The transparent substrate may be a cover lens receiving a touch applied to at least one surface thereof.
The transparent substrate may include at least one of tempered glass, polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), and polymethymethacrylate (PMMA).
According to another aspect of the present invention, there is provided a method of manufacturing a transparent panel, the method including: preparing a transparent panel; forming a graphene oxide layer on the transparent panel; providing an etching resist on a first area corresponding to a portion of the graphene oxide layer; and reducing a second area of the graphene oxide layer other than the first area.
The etching resist may have acid resistance.
The reducing of the second area may include reducing the second area using a gaseous or liquid reducing agent including at least one of iodic acid (HI), ammonia (NH3), sodium hydroxide (NaOH), potassium hydroxide (KOH), hydrogen sulfide, hydrazine, and aluminum powder.
The providing of the etching resist may be performed by forming a photoresist on the first area.
The providing of the etching resist may be performed by laminating a dry film resist (DFR) on the first area.
The forming of the graphene oxide layer may be performed by at least one of a gravure coating method, a slot die coating method, and a spray coating method.
The method may further include removing the etching resist from the first area.
The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Embodiments of the present invention will be described in detail with reference to the accompanying drawings. These embodiments will be described in detail in order to allow those skilled in the art to practice the present invention. It should be appreciated that various embodiments of the present invention are different but are not necessarily exclusive. For example, specific shapes, configurations, and characteristics described in an embodiment of the present invention may be implemented in another embodiment without departing from the spirit and scope of the present invention. In addition, it should be understood that positions and arrangements of individual components in each embodiment may be changed without departing from the spirit and scope of the present invention. Therefore, a detailed description provided below should not be construed as being restrictive. In addition, the scope of the present invention is defined only by the accompanying claims and their equivalents if appropriate. Similar reference numerals will be used to describe the same or similar functions throughout the accompanying drawing.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily practice the present invention.
As illustrated in
The transparent panel according to the present embodiment may be formed by forming a graphene oxide layer on at least a surface of a transparent substrate and selectively reducing only a portion of the graphene oxide. The graphene oxide may be mixed with water or an organic solvent and be easily applied to at least one surface of the transparent substrate in the form of a dispersion solution. As the graphene oxide has electrical conductivity only in the selectively reduced portion, it may function as a transparent electrode.
Hereinafter, for convenience of explanation, description will be provided by assuming that the transparent panel according to the present embodiment is applied to a touch screen. However, the description does not limit the applications of the transparent panel, and the transparent panel according to the present embodiment may also be applied to various devices other than touch screens.
Referring to
Referring to
As shown in
In general, in a device including a transparent panel such as a touch screen, transparent electrodes are formed on a transparent substrate by forming a transparent conductive material on a surface of the transparent substrate by sputtering, and then removing the transparent conductive material therefrom, with the exception of portions thereof allowing for a desired shape (pattern), by etching. However, in this case, steps are necessarily formed between the transparent electrodes and the portions in which the transparent electrodes are not formed by the etching process of removing the transparent conductive material. Here, an area of the transparent substrate from which the transparent electrodes are removed may be damaged by a chemical etching process. Further, in the case in which the transparent electrodes may not be properly removed in the etching process, and problems such as a short circuit between the electrodes, which are to be electrically separated from each other, may occur.
Referring to
The display device 350a may be a flat panel display device but is not limited thereto. The display device 350a is attached to a lower substrate of a touch screen—the second transparent substrate 315a of FIG. 3A—using the gasket adhesive portion 380a or the like. The gasket adhesive portion 380a may be disposed at edges of the display device 350a, and an air gap is formed in an area in which the gasket adhesive portion 380a is not provided, between the display device 350a and the second transparent substrate 315a. The air gap may alleviate a phenomenon that electrical noise generated in the display device 350a is transmitted to the first and second sensing electrodes 320a and 330a to hinder the determination of the touch.
In the touch screen of
The step between the first and second sensing electrodes 320a and 330a and the first and second transparent substrates 313a and 315a may increase a failure rate of a manufacturing process or may increase the possibility of the pattern exposure phenomenon of the first and second sensing electrodes 320a and 330a. It is known that the pattern exposure phenomenon of the first and second sensing electrodes 320a and 330a due to the step may be alleviated by the first and second adhesive layers 360a and 370a. However, in the case of a window-integrated touch screen in which the sensing electrodes 320a and 330a are directly formed on a surface of the cover lens 340a, additional transparent adhesive layers 360a and 370a are not disposed between the cover lens 340a and the sensing electrodes 320a and 330a, and thus it is difficult to prevent the pattern exposure phenomenon.
In addition, in a chemical etching process for forming the first and second sensing electrodes 320a and 330a, the remaining area of the first and second transparent substrates 313a and 315a in which the first and second sensing electrodes 320a and 330a are not formed may be damaged physically or chemically. This may cause scratches on the surfaces of the first and second transparent substrates 313a and 315a to increase a haze, thereby deteriorating transmittance and intensifying the pattern exposure phenomenon of the first and second sensing electrodes 320a and 330a.
A graphene oxide layer is formed on the separate first and second transparent substrates 313b and 315b by applying a graphene oxide a spray coating method, a slot die coating method, a gravure coating method or the like, and an etching resist is only formed on first areas 325b and 335b corresponding to portions of the graphene oxide layer. A graphene oxide refers to a liquid insulation solution prepared by melting a solid-type graphite material in water or other organic solvent. The graphene oxide has excellent dispersibility, and thus may be easily applied to the first and second transparent substrates 313b and 315b.
When the etching resist is formed on the first areas 325b and 335b of the graphene oxide layer, the entirety of the graphene oxide layer is reduced using a predetermined reducing agent. Examples of the reducing agent include at least one of iodic acid, ammonia (NH3), sodium hydroxide (NaOH), potassium hydroxide (KOH), hydrogen sulfide, hydrazine, and aluminum powder. The etching resist function as a shield so that the first areas 325b and 335b of the graphene oxide layer are not reduced by the reducing agent, and thus the etching resist may be formed of a material having acid resistance so as not to be melted by acid.
By reducing the graphene oxide layer, on which the etching resist is formed, using a reducing agent, the first areas 325b and 335b blocked from being in contact with the reducing agent due to the etching resist may have non-electrical conductivity as the properties of the graphene oxide. On the other hand, second areas, that is, the remaining areas with the exception of the first areas 325b and 335b, are reduced by the reducing agent to thereby obtain electrical conductivity. Accordingly, the first and second sensing electrodes 320b and 330b are formed in the second areas by a reduction process without a chemical etching or washing process. Also, no step is formed between the second areas having electrical conductivity in which the first and second sensing electrodes 320b and 330b are formed and the first areas 325b and 335b having non-electrical conductivity, as illustrated in
That is, the graphene oxide is formed on the first and second transparent substrates 313b and 315b regardless of whether they have electrical conductivity or non-electrical conductivity. Thus, compared to the embodiment illustrated in
Referring to
The graphene oxide layer may be formed by applying a solution, in which a solid-type graphite is diluted in water or an organic solvent, to the transparent substrate by a gravure coating method, a slot die coating method, a spray coating method or the like. The graphene oxide solution has excellent dispersibility, and thus it is easy to form the graphene oxide layer on the transparent substrate. In addition, the graphene oxide solution has non-electrical conductivity, that is, insulating properties.
After the graphene oxide layer is formed, an etching resist is formed on a first area corresponding to at least a portion of the graphene oxide layer (S420). The etching resist is formed on the first area of the graphene oxide layer intended to maintain its insulating properties without being reduced. Also, in order to prevent the first area from being reduced in the case that the etching resist is affected by a reducing agent including acid in a subsequent reducing process, the etching resist may have excellent acid resistance.
After the etching resist is formed on the first area of the graphene oxide layer, a second area, on which the etching resist is not formed, is reduced (S430). A gaseous or liquid reducing agent may be used in the reducing process, and as described above, at least one of iodic acid (HI), ammonia (NH3), sodium hydroxide (NaOH), potassium hydroxide (KOH), hydrogen sulfide, hydrazine, and aluminum powder may be used therefor. When the reducing process is completed, the etching resist is removed (S440), and the manufacturing process of the transparent panel is completed.
After the above-described operations, the first area of the graphene oxide layer maintains the insulating properties of the graphene oxide, and only the second area is reduced to obtain electrical conductivity. Thus, a transparent electrode may be formed on the transparent substrate without a thickness difference or a step, and in particular, when the transparent panel is applied to a window-integrated touch screen in which a transparent substrate is directly used as a cover lens, a pattern exposure phenomenon may be minimized.
Referring to
The first area of the graphene oxide layer 520, on which the etching resist 530 is formed, corresponds to an area excepting for the transparent electrodes, the area in which the properties of a graphene oxide having non-electrical conductivity are maintained. When the graphene oxide layer 520 having the etching resist 530 formed thereon is reduced, only a second area 525 of the graphene oxide layer 520, which is not blocked by the etching resist 530 from being in contact with a reducing agent, is reduced to thereby obtain electrical conductivity.
After the reducing process, the etching resist 530 is removed to complete the manufacturing process of the transparent panel. As shown in
As set forth above, according to embodiments of the present invention, a graphene oxide layer is formed on at least a surface of a transparent substrate, and the graphene oxide layer includes a first area having non-electrical conductivity and a second area having electrical conductivity. Thus, a transparent electrode may be formed without a step, whereby a pattern exposure phenomenon may be alleviated while the manufacturing process of a transparent panel may be simplified.
While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2011-0136355 | Dec 2011 | KR | national |
