TWI427366B - Liquid crystal display with touch panel - Google Patents

Description

Touch screen

The present invention relates to a liquid crystal display, and more particularly to a touch type liquid crystal display.

The liquid crystal display is one of the best display modes because of its low power consumption, miniaturization, and high-quality display. At present, the more commonly used liquid crystal display is a TN (Twisted Nematic) mode liquid crystal display (TN-LCD). For the TN-LCD, when no voltage is applied to the electrode, the liquid crystal display is in the "OFF" state, and the light energy is transmitted through the liquid crystal display; when a certain voltage is applied to the electrode, the liquid crystal display is in the "ON" state. The long axis direction of the liquid crystal molecules is arranged in the direction of the electric field, and the light cannot pass through the liquid crystal display, so that the light is blocked. Optionally applying a voltage across the electrodes can reveal different patterns.

In recent years, with the development of high-performance and diversified electronic devices such as mobile phones, touch navigation systems, integrated computer monitors, and interactive televisions, electronic devices with light-transmissive touch screens mounted on the display surface of liquid crystal displays have gradually increase. The user of the electronic device visually confirms the display content of the liquid crystal display located on the back of the touch screen through the touch screen, and presses the touch screen to operate by using a finger or a pen. Thereby, various functions of the electronic device using the liquid crystal display can be operated. The touch screen can be generally divided into four types according to the working principle and the transmission medium, which are resistive, capacitive inductive, infrared, and surface acoustic wave. Among them, the capacitive touch screen has the advantages of simple structure, low cost and durability. Universal application.

However, integrating the touch screen into the liquid crystal display will inevitably increase the thickness of the liquid crystal display, which is disadvantageous for the miniaturization and thinning of the liquid crystal display and the electronic device using the liquid crystal display.

In view of this, it is necessary to provide a touch type liquid crystal panel having a thin thickness.

A touch screen LCD, comprising: a touch screen and a liquid crystal display, wherein: the touch screen comprises: a common substrate; a first transparent conductive layer, the first transparent conductive layer is disposed on an upper surface of the common substrate; And at least one first electrode and at least one second electrode, the first electrode and the second electrode are disposed on an upper surface of the common substrate and electrically connected to the first transparent conductive layer, and the liquid crystal display is sequentially from top to bottom The invention comprises: an upper substrate; a second transparent conductive layer; a first alignment layer; a liquid crystal layer; a second alignment layer; a thin film transistor panel; and a second polarizing layer, the upper substrate of the liquid crystal display For the common substrate of the touch screen, the second transparent conductive layer serves as the first polarizing layer of the liquid crystal display.

A touch screen LCD comprising a touch screen and a liquid crystal display, the liquid crystal display comprising, in order from top to bottom, an upper substrate; a second transparent conductive layer; a first alignment layer; a liquid crystal layer; a second alignment layer; a thin film transistor panel; and a second polarizing layer, the second transparent conductive layer simultaneously serving as a first polarizing layer of the liquid crystal display; the touch screen using the upper substrate of the liquid crystal display as a substrate The upper surface of the substrate is provided with a first transparent conductive layer of the touch screen and at least one first electrode and at least one second electrode respectively electrically connected to the first transparent conductive layer.

Compared with the prior art, the touch screen in the touch LCD screen is shared with the liquid crystal display The use of a common substrate, thus having a thinner thickness and a simple structure, simplifies the manufacturing process, reduces manufacturing costs, improves backlight utilization, and improves display quality.

20‧‧‧Touch LCD screen

202‧‧‧First transparent conductive layer

204‧‧‧Second transparent conductive layer

206‧‧‧First electrode

208‧‧‧second electrode

210‧‧‧Common substrate

212‧‧‧First alignment layer

230‧‧‧Liquid layer

222‧‧‧Second alignment layer

220‧‧‧Thin film transistor panel

224‧‧‧Second polarizing layer

240‧‧‧Transparent protective film

143‧‧‧Nano carbon nanotube fragments

145‧‧・Nano carbon tube

250‧‧‧Touch sensing area

1 is a cross-sectional structural view of a touch type liquid crystal panel according to an embodiment of the present technical solution.

2 is a top plan view of an upper substrate in a touch type liquid crystal panel according to an embodiment of the present disclosure.

FIG. 3 is a scanning electron micrograph of a carbon nanotube film in a touch type liquid crystal panel according to an embodiment of the present technology.

4 is a schematic view showing the structure of a carbon nanotube segment in the carbon nanotube film of FIG.

The touch liquid crystal panel of the present technical solution will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 and FIG. 2 , the embodiment of the present disclosure provides a touch-type liquid crystal panel 20 including a single-point capacitive touch screen and a liquid crystal display screen sharing the substrate with the touch screen.

The single-point capacitive touch screen includes a common substrate 210, a first transparent conductive layer 202, at least a first electrode 206, and at least a second electrode 208. The first transparent conductive layer 202, the at least one first electrode 206 and the at least one second electrode 208 are disposed on the upper surface of the common substrate 210, the at least one first electrode 206 and the at least one second electrode 208 and the first A transparent conductive layer 202 is electrically connected. The at least one first electrode 206 may be disposed at one end of the first transparent conductive layer 202 along the first direction, such as the X direction, and the at least one second electrode 208 may be disposed at the first transparent conductive layer 202 along the second direction, such as Y. One end of the direction. The first direction is perpendicular to the second direction. In the present specification, "upper" is a direction close to the touch surface, and "down" is a direction away from the touch surface.

Further, the single-point capacitive touch screen may include two first electrodes 206 and two Second electrode 208. The two first electrodes 206 and the two second electrodes 208 may be respectively disposed on four corners or four sides of the first transparent conductive layer 202. In this embodiment, the two first electrodes 206 are disposed at two ends of the first transparent conductive layer 202 in the first direction, and are electrically connected to the first transparent conductive layer 202. The two second electrodes 208 are disposed at two ends of the first transparent conductive layer 202 in the second direction and are electrically connected to the first transparent conductive layer 202. The middle of the first transparent conductive layer 202 is a touch sensing area 250. The first transparent conductive layer 202 has good transmittance.

The liquid crystal display screen shares the common substrate 210 with the touch screen, and further includes a second transparent conductive layer 204, a first alignment layer 212, a liquid crystal layer 230, a second alignment layer 222, and a film from top to bottom. The transistor panel 220 and a second polarizing layer 224.

The second transparent conductive layer 204 is disposed on a lower surface of the common substrate 210. The first alignment layer 212 is disposed on a lower surface of the second transparent conductive layer 204. The second alignment layer 222 is disposed on the upper surface of the thin film transistor panel 220 and opposite to the first alignment layer 212. The liquid crystal layer 230 is disposed between the first alignment layer 212 and the second alignment layer 222. The second polarizing layer 224 is disposed on a lower surface of the thin film transistor panel 220. It will be appreciated that additional layers may optionally be interposed between the various layers as desired for various functions.

The common substrate 210 is both a substrate of the touch screen and an upper substrate of the liquid crystal display. The second transparent conductive layer 204 is both an upper electrode of the liquid crystal display panel and a function of applying a voltage to the liquid crystal layer 230, and is also a first polarizing layer and functions as a polarizing light. Therefore, the touch type liquid crystal panel 20 has a thin thickness and a simple structure, simplifies the manufacturing process, reduces the manufacturing cost, improves the utilization ratio of the backlight, and improves the display quality.

It can be understood that the specific structure of the liquid crystal display is not limited to the structure of the above embodiment, as long as the liquid crystal display and the touch screen share the common substrate 210 within the protection scope of the present invention.

Specifically, the first transparent conductive layer 202 can be a first carbon nanotube layer, and the second transparent conductive layer 204 can be a second carbon nanotube layer.

In the touch screen, the first carbon nanotube layer includes a plurality of carbon nanotubes. Preferably, the carbon nanotubes in the first first carbon nanotube layer are disorderly arranged or extend in a preferred orientation along the first direction and the second direction, respectively. Preferably, the first carbon nanotube layer is a pure carbon nanotube layer composed of a carbon nanotube, so that the transmittance of the touch screen can be improved.

When the carbon nanotubes in the first carbon nanotube layer are disorderly arranged, the conductivity of the first carbon nanotube layer is isotropic. The isotropic first carbon nanotube layer can be formed by coating a surface of the common substrate 210 with a carbon nanotube dispersion.

When the carbon nanotubes in the first carbon nanotube layer extend in a preferred orientation in the first direction and the second direction, respectively, the first carbon nanotube layer has better conductivity in the first direction and the second direction. Sex, so that the sensitivity of the touch screen can be improved. Specifically, the first carbon nanotube layer can be formed by laying one or more carbon nanotube film on the upper surface of the common substrate 210 in the first direction and the second direction, so that the first The carbon nanotubes in the carbon nanotube layer extend in a preferred orientation along the first direction and the second direction, respectively. Therefore, the first carbon nanotube layer may be formed by laminating a plurality of conductive anisotropic carbon nanotube films in a first direction and a second direction, respectively, so that the first carbon nanotube layers are respectively in mutual The electrical conductivity in the first and second directions of the vertical is greater than the electrical conductivity in the other direction. Further, the first carbon nanotube layer may include a composite film composed of the carbon nanotube film and the polymer material. The carbon nanotube film is obtained by drawing from a carbon nanotube array.

Referring to FIG. 3, the carbon nanotube film is a self-supporting structure composed of a plurality of carbon nanotubes. The plurality of carbon nanotubes extend in a preferred orientation along the same direction. The preferred orientation means that the overall extension direction of most of the carbon nanotubes in the carbon nanotube film is substantially in the same direction. Moreover, the overall extension direction of the majority of the carbon nanotubes is substantially parallel to the surface of the carbon nanotube film. Further, most of the carbon nanotubes in the carbon nanotube film are connected end to end by a van der Waals attractive force. Specifically, each of the carbon nanotubes of the majority of the carbon nanotubes extending in the same direction in the carbon nanotube film is connected end to end with the carbon nanotubes adjacent in the extending direction by van der Waals force . Of course, there are a small number of randomly arranged carbon nanotubes in the carbon nanotube film, and these carbon nanotubes do not significantly affect the overall orientation of most of the carbon nanotubes in the carbon nanotube film. The self-supporting carbon nanotube film does not require a large-area carrier support, and as long as the support force is provided on both sides, it can be suspended in the whole to maintain its own film state, that is, the carbon nanotube film is placed (or When fixed on two supports arranged at a certain distance, the carbon nanotube film located between the two supports can be suspended to maintain its own film state. The self-supporting is mainly achieved by the presence of continuous carbon nanotubes extending through the end-to-end extension of the van der Waals force in the carbon nanotube film.

Specifically, the plurality of carbon nanotubes extending substantially in the same direction in the carbon nanotube film are not absolutely linear and may be appropriately bent; or are not completely aligned in the extending direction, and may be appropriately deviated from the extending direction. . Therefore, it is not possible to exclude partial contact between the carbon nanotubes juxtaposed in the majority of the carbon nanotubes extending substantially in the same direction of the carbon nanotube film.

Referring to FIG. 4, in particular, the carbon nanotube film comprises a plurality of continuous and aligned carbon nanotube segments 143. The plurality of carbon nanotube segments 143 pass through the van der Waals The tail is connected. Each of the carbon nanotube segments 143 includes a plurality of carbon nanotubes 145 that are parallel to each other, and the plurality of mutually parallel carbon nanotubes 145 are tightly coupled by van der Waals force. The carbon nanotube segments 143 have any length, thickness, uniformity, and shape. The carbon nanotubes 145 in the carbon nanotube film are arranged in a preferred orientation in the same direction.

A specific method for extracting the carbon nanotube film from the carbon nanotube array includes: (a) selecting a carbon nanotube segment 143 from the carbon nanotube array, which is preferably employed in this embodiment. a tape or adhesive strip having a width contacting the array of carbon nanotubes to select a carbon nanotube segment 143 having a width; (b) pulling the selected nano at a certain speed by moving the stretching tool The carbon tube segments 143 are pulled out of the plurality of carbon nanotube segments 143 end to end to form a continuous carbon nanotube film. The plurality of carbon nanotubes are arranged side by side such that the carbon nanotube segments 143 have a certain width. When the selected carbon nanotube segment 143 is gradually separated from the growth substrate of the carbon nanotube array in the pulling direction by the pulling force, it is associated with the selected carbon nanotube segment 143 due to the effect of van der Waals force. The adjacent other carbon nanotube segments 143 are successively pulled out one after the other to form a continuous, uniform carbon nanotube film having a certain width and a preferred orientation.

The carbon nanotube film has a minimum electrical resistance in the stretching direction and a maximum electrical resistance in a direction perpendicular to the stretching direction, and thus has an electrical anisotropy, that is, an anisotropic conductivity.

Since the plurality of carbon nanotube film can be stacked on each other or arranged side by side, the length and width of the first carbon nanotube layer are not limited, and can be set according to actual needs. In addition, the carbon nanotube film has an ideal transmittance (the visible light transmittance of the single-layer carbon nanotube film is more than 85%), and the carbon nanotube film in the first carbon nanotube layer is The number of layers is not limited as long as it has an ideal transmittance.

Further, the first carbon nanotube layer may include a composite film composed of the carbon nanotube film and a polymer material. The polymer material is uniformly distributed in a gap between the carbon nanotubes in the carbon nanotube film. The polymer material is a transparent polymer material, and the specific material thereof is not limited, and includes polystyrene, polyethylene, polycarbonate, polymethyl methacrylate (PMMA), polycarbonate (PC), and terephthalic acid. Ethylene glycolate (PET), phenylcyclobutene (BCB), polycycloolefin, and the like. For example, the first carbon nanotube layer may be a composite film in which two layers are laid in the first direction and the second direction and laminated with a carbon nanotube film and PMMA. The carbon nanotube composite film has a thickness of from 0.5 nm to 100 μm.

Further, the first carbon nanotube layer may include an etched or laser treated carbon nanotube film. By laser treatment, a plurality of laser cutting lines can be formed on the surface of the carbon nanotube film to further enhance the conductive anisotropy of the carbon nanotube film. The laser cutting line is substantially parallel to the arrangement direction of the carbon nanotubes in the carbon nanotube film.

The common substrate 210 is a transparent thin plate, and the material of the common substrate 210 may be glass, quartz, diamond, plastic or resin. The common substrate 210 has a thickness of 1 mm to 1 cm. In this embodiment, the material of the common substrate 210 is PET, and the friction is 2 mm. It is to be understood that the material forming the common substrate 210 is not limited to the materials listed above, and any material that can serve as a support and has a good transparency is within the scope of the present invention.

The two first electrodes 206 and the two second electrodes 208 of the touch screen are formed of a conductive material, and may be selected as a metal layer, a conductive polymer layer or a carbon nanotube layer. The material of the metal layer may be selected from a metal having good conductivity such as gold, silver or copper. The material of the conductive polymer layer may be selected from the group consisting of polyacetylene, polyparaphenylene, polyaniline, polyimibe, polypyrrole, polythiophene and the like. In this embodiment, the first electrode 206 and the second electrode The poles 208 are conductive silver paste strips respectively formed on the upper surface of the common substrate 210 by screen printing.

In addition, a transparent protective film 240 may further be disposed on the upper surface of the first transparent conductive layer 202. The transparent protective film 240. The upper surface of the first transparent conductive layer 202 may be directly bonded by an adhesive, or may be pressed together with the first transparent conductive layer 202 by a hot pressing method. The transparent protective film 240 may be a surface-hardened, smooth scratch-resistant plastic layer or a resin layer formed of a material such as phenylcyclobutene (BCB), polyester, or acrylic resin. In the embodiment, the material of the transparent protective film 240 is PET, which is used for protecting the first transparent conductive layer 202 to improve durability. The transparent protective film 240 can be used to provide some additional functions such as reducing glare or reducing reflection.

In the liquid crystal display, the second transparent conductive layer 204 may include a plurality of carbon nanotubes arranged in a preferred orientation along the first direction. Preferably, the second transparent conductive layer 204 is a pure carbon nanotube layer composed of a carbon nanotube, so that the transmittance of the touch screen can be improved. Specifically, the second transparent conductive layer 204 includes one or more laminated carbon nanotubes laminated and disposed in a first direction. Since the carbon nanotubes in the second transparent conductive layer 204 are preferentially aligned in the first direction, the second transparent conductive layer 204 can function as the first polarizing layer, and the polarization direction is perpendicular to the first direction. Two directions. Since the second transparent conductive layer 204 is transparent and electrically conductive, it can be used as an upper electrode of a liquid crystal display.

The material of the second polarizing layer 224 may be the same as the material of the second transparent conductive layer 204. The material of the second polarizing layer 224 may also be a polarizing material commonly used in the prior art, such as a dichroic organic polymer material, and specifically may be an iodine-based material or a dye material. The second polarizing layer 224 functions as a touch screen to be disposed on the touch screen. The light emitted by the light guide plate on the lower surface of the 20 is polarized to obtain light polarized in a single direction. The polarization direction of the second polarizing layer 224 is perpendicular to the polarization direction of the second transparent conductive layer 204, that is, the polarization direction of the second polarizing layer 224 is the first direction.

The lower surface of the first alignment layer 212 may include a plurality of parallel first trenches, and the upper surface of the second alignment layer 222 may include a plurality of parallel second trenches to align liquid crystal molecules. The arrangement direction of the first trenches of the first alignment layer 212 is perpendicular to the alignment direction of the second trenches of the second alignment layer 222, so the liquid crystal molecules between the first alignment layer 212 and the second alignment layer 222 are in two The alignment angle between the alignment layers produces a 90-degree rotation, thereby functioning as an optical rotation, and the polarization direction of the polarized light of the second polarizing layer 224 is rotated by 90 degrees. The material of the first alignment layer 212 and the second alignment layer 222 may be polystyrene and its derivatives, polyimine, polyvinyl alcohol, polyester, epoxy resin, polyurethane, polydecane, and the like. The first trench and the second trench may be formed by a prior art film rubbing method, a tilted vapor deposition SiOx film method, and a microgroove processing method on the film. In this embodiment, the first alignment layer 212 and the second alignment layer 222 are made of polyimide and have a thickness of 1 to 50 micrometers.

The liquid crystal layer 230 includes a plurality of long rod-shaped liquid crystal molecules. The liquid crystal material of the liquid crystal layer 230 is a liquid crystal material commonly used in the prior art. The thickness of the liquid crystal layer 230 is 1 to 50 micrometers. In the embodiment, the thickness of the liquid crystal layer 230 is 5 micrometers.

The specific structure inside the thin film transistor panel 220 is not shown in FIG. 1, but those skilled in the art may know that the thin film transistor panel 220 may further include a transparent lower substrate formed on the upper surface of the lower substrate. A plurality of thin film transistors, a plurality of primitive electrodes, and a display driving circuit. The plurality of thin film transistors are connected in one-to-one correspondence with the primitive electrodes, and the plurality of thin film transistors are electrically connected to the display driving circuit through the source lines and the gate lines. The primitive electrode is under the control of the thin film transistor and the second through The conductive layer 204 is matched to apply an alignment electric field to the liquid crystal layer 230, thereby aligning the liquid crystal molecules in the liquid crystal layer 230. The plurality of primitive electrodes are opposite to the touch sensing area 250.

In use, a predetermined voltage is applied to the first transparent conductive layer 202. A voltage is applied to the first transparent conductive layer 202 through the first electrode 206 and the second electrode 208, thereby forming an equipotential surface on the first transparent conductive layer 202. When a touch object such as a finger or a pen presses or approaches the touch screen, a coupling capacitance is formed between the touch object and the first transparent conductive layer 202. For high frequency currents, the capacitor is a direct conductor, so the finger draws a portion of the current from the point of contact. This current flows from the first electrode 206 and the second electrode 208 on the touch screen, respectively, and the current flowing through the first electrode 206 and the second electrode 208 is proportional to the distance from the finger to the electrode, thereby obtaining the position of the touch point.

The touch screen in the touch liquid crystal panel provided by the embodiment of the present technical solution shares a common substrate with the liquid crystal display, and thus has a thin thickness and a simple structure, simplifies the manufacturing process, reduces the manufacturing cost, and improves the utilization rate of the backlight. Improve display quality.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

20‧‧‧Touch LCD screen

202‧‧‧First transparent conductive layer

204‧‧‧Second transparent conductive layer

210‧‧‧Common substrate

212‧‧‧First alignment layer

230‧‧‧Liquid layer

222‧‧‧Second alignment layer

220‧‧‧Thin film transistor panel

224‧‧‧Second polarizing layer

240‧‧‧Transparent protective film

Claims (7)

A touch screen LCD, comprising a touch screen and a liquid crystal display, wherein the touch screen comprises: a common substrate; a first transparent conductive layer, the first transparent conductive layer is disposed on an upper surface of the common substrate; At least one first electrode and at least one second electrode, the first electrode and the second electrode are disposed on an upper surface of the common substrate and electrically connected to the first transparent conductive layer, and the liquid crystal display comprises sequentially from top to bottom An upper transparent substrate; a second transparent conductive layer; a first alignment layer; a liquid crystal layer; a second alignment layer; a thin film transistor panel; and a second polarizing layer, wherein the liquid crystal display is improved The upper transparent substrate is a first polarizing layer of the liquid crystal display, and the first transparent conductive layer is a first carbon nanotube layer, the first The carbon nanotube layer comprises a plurality of carbon nanotubes, the plurality of carbon nanotubes being disorderly arranged or extending in a preferred orientation along the first direction and the second direction, the first direction being perpendicular to the second direction, the first A second transparent conductive layer is a carbon nanotube layer, the carbon nanotube layer comprises a plurality of second CNTs, the plurality of carbon nanotubes oriented in a first direction extending preferred. The touch liquid crystal panel of claim 1, wherein the first transparent conductive layer comprises a plurality of carbon nanotube films, and the carbon nanotube film comprises a plurality of carbon nanotube tubes Most of the plurality of carbon nanotubes extend substantially in the same direction, and the plurality of carbon nanotube films are stacked in the first direction and the second direction, respectively. The touch liquid crystal panel of claim 2, wherein each of the plurality of carbon nanotubes extending substantially in the same direction in the carbon nanotube film is adjacent to each other in the extending direction The carbon nanotubes are connected end to end by van der Waals force. The touch liquid crystal panel of claim 1, wherein the first transparent conductive layer is a carbon nanotube composite layer, and the carbon nanotube composite layer comprises a carbon nanotube film and a polymer material uniformly distributed. In the carbon nanotube film. The touch liquid crystal panel of claim 1, wherein the at least one first electrode is two first electrodes, and the at least one second electrode is two second electrodes, the two first electrodes The two transparent electrodes are disposed at two ends of the first transparent conductive layer along the first direction, and the two second electrodes are disposed at both ends of the first transparent conductive layer along the second direction. The touch liquid crystal panel of claim 1, further comprising a transparent protective film disposed on the upper surface of the first transparent conductive layer. A touch screen LCD comprising a touch screen and a liquid crystal display, wherein the liquid crystal display comprises, in order from top to bottom, an upper substrate; a second transparent conductive layer; a first alignment layer; a liquid crystal layer; a second alignment layer; a thin film transistor panel; and a second polarizing layer, the second transparent conductive layer simultaneously serving as a first polarizing layer of the liquid crystal display; the touch screen is a liquid crystal display The upper substrate is a substrate, and the upper surface of the substrate is provided with a first transparent conductive layer of the touch screen and at least one first electrode and at least one second electrode electrically connected to the first transparent conductive layer, wherein the first transparent conductive layer is a first carbon nanotube layer, the first carbon nanotube layer comprising a plurality of carbon nanotubes, the plurality of nanocarbons The tube is disorderly arranged or extended in a preferred orientation along the first direction and the second direction, the first direction being perpendicular to the second direction, the second transparent conductive layer being a second carbon nanotube layer, the second nanometer The carbon tube layer includes a plurality of carbon nanotubes that extend in a preferred orientation along the first direction.