Patent Application
20140104234
1. Technical Field
The present invention relates to a touch sensor, and more particularly to a capacitive touch sensor locally formed with an electrostatic capacitor in which a transparent base plate such as a transparent resin film or a glass plate is constituted as a medium such that one surface of the medium is formed with one electrode, of the electrostatic capacitor, made of transparent conductive resin and an opposite surface thereof is formed with an electrode when a user's finger is touched thereon, thereby sensing such a phenomenon as an electric signal and detecting a touch position.
2. Description of Related Art
In general, a touch sensor is a device in which, when a user touches an image displayed on a screen with one's finger, a touch pen, or the like, a touch point is grasped in response to such a touch. This touch sensor is applied to, for example, a touch pad or a touch screen.
This touch sensor is typically manufactured as a structure overlaid on a flat display LCD panel or a PDP panel. The touch sensor senses a touch position of the user's finger or the touch pen to convert the touch position into a coordinate on an image screen, independently from an image displayed on the screen, and such coordinate information is transmitted to an image control device. The image control device composes the position information and the image screen received from the touch sensor and controls an image so as to perform necessary action. An actual application example of such a touch sensor includes an automated teller machine in a bank, a ticket vendor in a train station, a mobile information device, a portable telephone, and the like, and the touch sensor is in the spotlight for education.
The touch sensor is embodied by several methods, for example, methods using resistance, capacitance, surface acoustic waves, infrared light, and cameras, different from each other in terms of techniques according to the size and use of a display screen.
Among them, a capacitive touch sensor is typically manufactured by applying an ITO film on one surface or both surfaces of a thin glass plate or a transparent resin film and etching the ITO film as a specific pattern. Such an ITO film is optically transparent and restrictively has high electrical conductivity. Thus, the ITO film serves as an electrode of a capacitor and a signal transmission conductor together. Touch coordinate information of the touch sensor manufactured via the ITO film is transferred to square sides of a touch screen through the conductor formed of the ITO film. Here, the square sides are connected to a control circuit so as to transmit a touch coordinate signal to the control circuit.
However, the capacitive touch sensor manufactured via the ITO film has the following problems.
First, the ITO film constituting the touch sensor has high production costs because it is quite expensive due to rarity of indium which is a raw material thereof.
In addition, the ITO film has high manufacturing costs because of being formed by sputtering in a vacuum device. The ITO film has a complicated manufacturing process since the ITO film is formed in an electrode pattern by optical lithography and is manufactured by repeating 3 or 4 times the process, thereby being costly for manufacturing and very high price.
Besides, the ITO film serves as the transparent electrode and the signal transmission conductor and electrical resistance of the ITO film is a serious obstructive factor during high speed signal processing. Therefore, the ITO film generates serious obstacle to a multipoint touch and signal processing in an area having the size of 20 inches or more in a diagonal direction.
Therefore, the present invention has been made in view of the above problems of the capacitive touch sensor manufactured by the conventional ITO film, and it is an object of the present invention to provide a capacitive touch sensor capable of being applied to a large touch screen or a multipoint touch by achieving simplification of a production process and low manufacturing costs and increasing signal processing speed.
In accordance with an aspect of the present invention, a capacitive touch sensor for detecting a touch point of a user includes a transparent non-conductive base plate, a transparent electrode thin film formed on one surface of the transparent non-conductive base plate, the transparent electrode thin film being formed in a net form in which a plurality of polygonal or circular unit cells are connected to each other through signal transmission conductors in horizontal, vertical, and diagonal directions, and a control board in which the transparent electrode thin film forms a first electrode of a charge capacitor and forms a second electrode of the charge capacitor when the user touches the other surface of the transparent non-conductive base plate such that the control board receives through the conductors a touch signal induced in the first electrode by a user's touch when the user touches the other surface of the transparent base plate as the second electrode and detects a touch point of the user.
Each of the unit cells of the transparent electrode thin film may be connected to other unit cells adjacent in the horizontal and vertical directions through the signal transmission conductors, and be connected to other unit cells adjacent in one diagonal direction through the signal transmission conductor, and the signal transmission conductors connecting the unit cells may be insulated and electrically isolated by transparent insulation films at intersection points of the signal transmission conductors.
The signal transmission conductors connecting the unit cells may extend up to an edge of the transparent non-conductive base plate and be connected to the control board at the edge, and the signal transmission conductors located in the vicinity of the edge of the transparent non-conductive base plate may be formed with expansion portions having a larger width than the signal transmission conductors connecting the unit cells.
In the signal transmission conductors connecting the unit cells, a coordinate of each signal transmission conductor which connects the unit cells in the vertical direction and extends up to the edge may be set to a first axis coordinate, a coordinate of each signal transmission conductor which connects the unit cells in the horizontal direction and extends up to the edge may be set to a second axis coordinate, and a coordinate of each signal transmission conductor which connects the unit cells in one diagonal direction and extends up to the edge may be set to a third axis coordinate, and the control board may combine and analyze charge signals transmitted from the signal transmission conductors set to the first, second, and third axis coordinates according to the user's touch, and may detect a touch point of the user. In addition, a coordinate of a signal transmission conductor which connects the unit cells in the other diagonal direction and extends up to the edge may be set to a fourth axis coordinate such that a charge signal generated according to the user's touch is transmitted to the control board through the conductor.
Each of the unit cells may be configured of a plurality of unit cell pads which are separated from each other, and each of the unit cell pads may be connected to any one of the signal transmission conductors defining the respective axes. Herein, in the plural unit cell pads coming into contact with the signal transmission conductors defining the respective axes, sums of areas of the unit cell pads coming into contact with the respective axes may be equally formed.
The control board may simultaneously apply pulse train signals to the signal transmission conductors defining the first axis coordinate and then sequentially detect induced charge signals generated by the user's touch in the signal transmission conductors defining the other axis coordinates, may simultaneously apply pulse train signals to the signal transmission conductors defining the second axis coordinate and then sequentially detect induced charge signals generated by the user's touch in the signal transmission conductors defining the other axis coordinates, and may detect the first and second axis coordinates according to combination of the coordinates of the induced charge signals detected through the above processes and detect a touch position of the user. In this case, the control board may produce a third axis coordinate or a fourth axis coordinate passing though the combined first and second axis coordinates, and when the produced third axis coordinate or fourth axis coordinate coincides with the detected third axis coordinate or fourth axis coordinate by comparison therewith, may grasp the associated coordinate as a actual touch position, when the produced third axis coordinate or fourth axis coordinate does not coincides with the detected third axis coordinate or fourth axis coordinate, may identify the associated coordinate as a virtual image to detect a touch position of the user.
The transparent electrode thin film may be printed and applied on one surface of the transparent non-conductive base plate.
In accordance with another aspect of the present invention, a capacitive touch sensor for detecting a touch point of a user includes a transparent non-conductive base plate, a transparent electrode thin film formed on one surface of the transparent non-conductive base plate, the transparent electrode thin film being formed such that a plurality of polygonal or circular unit cells are connected to other unit cells adjacent in horizontal and vertical directions through signal transmission conductors, and a control board in which the transparent electrode thin film forms a first electrode of a charge capacitor and forms a second electrode of the charge capacitor when the user touches the other surface of the transparent non-conductive base plate such that the control board receives through the conductors a touch signal induced in the first electrode by a user's touch when the user touches the other surface of the transparent base plate as the second electrode and detects a touch point of the user.
Each of the unit cells may be configured therein of a plurality of unit cell pads which are separated from each other, and the unit cell pads may be connected to unit cell pads formed in other unit cell adjacent thereto, thereby forming the unit cells.
Each of the unit cell pads formed in the unit cell may be connected to any one of the signal transmission conductors, and in the plural unit cell pads connected with the signal transmission conductors, sums of areas of the unit cell pads with the respective signal transmission conductors may be equally formed.
The signal transmission conductors connecting between the unit cell pads may be insulated and electrically isolated by transparent insulation films at intersection points of the signal transmission conductors.
An X-axis transparent electrode thin film formed by combination of the unit cell pads connected with the signal transmission conductors in the vertical direction and a Y-axis transparent electrode thin film formed by combination of the unit cell pads connected with the signal transmission conductors in the horizontal direction may be respectively coupled to transparent base plates, and then be coupled to each other so as to be electrically isolated through a transparent adhesive sheet, thereby forming the transparent electrode thin film.
A capacitive touch sensor according to the present invention has effects of significant simplification of a production process and a reduction in manufacturing costs by separating two functions provided by an ITO film, namely, a function as one electrode of a capacitor and a function as a signal transmission conductor, without using the expensive ITO film such that the electrode is replaced with a transparent electrode thin film made of transparent conductive resin and the signal transmission conductor is replaced with a thin metallic wire formed by a printed electronic method so as not to be identified with the naked eye. In addition, it may also be possible to recognize a multipoint touch by adopting a design capable of obtaining position information with respect to a third axis and a fourth axis.
The above and other objects, 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:
Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.
As shown in
As shown in
The transparent electrode thin film 200 formed on one surface of the transparent base plate 100 forms a first electrode of a charge capacitor and the other surface of the transparent base plate 100 forms a second electrode of the charge capacitor by a user's finger touching the other surface. A charge signal induced in the transparent electrode thin film 200 as the first electrode is transmitted to the control board through signal transmission conductors 400 and the control board analyses the charge signal transmitted from the transparent electrode thin film 200 as the first electrode and detects the touch point of the user.
The transparent base plate 100 is a non-conductive plate, having a rectangular shape, through which light may pass. The transparent base plate 100 may be formed of a transparent thin glass plate or various polymer resin films such as polyester. The transparent base plate 100 constitutes a body which is a base of the touch sensor, and the transparent electrode thin film 200 is applied to one surface of the transparent base plate 100 to form the first electrode.
The transparent electrode thin film 200 formed on one surface of the transparent base plate 100 is formed in a net form in which a plurality of polygonal or circular unit cells 300 are arranged in horizontal, vertical, and diagonal directions. Each of the unit cells 300 is connected to other unit cells 300 adjacent in the horizontal and vertical directions through respective signal transmission conductors 410 and 420, and is connected to other unit cells 300 adjacent in one diagonal direction through a signal transmission conductor 430. Intersection points of the horizontal, vertical, and diagonal signal transmission conductors 400 (410, 420, and 430) connecting the unit cells 300 occur in central points of the unit cells 300, respectively. In the embodiment of the present invention, the intersection points are electrically isolated by respective transparent insulation films 500 such that short circuits are not generated at the intersection points.
The signal transmission conductors 400 connecting the unit cells 300 extend up to an edge of the transparent non-conductive base plate 100 and are connected to the control board at the edge. The signal transmission conductors 400 (410, 420, and 430) located adjacent in the vicinity of the edge of the transparent non-conductive base plate 100 are formed with expansion portions 411, 412, and 413 having a larger width than the signal transmission conductors connecting the unit cells 300, thereby facilitating connection of the conductors and the control board.
In the embodiment of the present invention, the signal transmission conductors 400 connecting the unit cells 300 define coordinate axes of the respective unit cells 300. For example, the coordinate of each signal transmission conductor 410 which connects the unit cells 300 in the vertical direction and extends up to the edge is set to an X-axis coordinate as a first axis coordinate, the coordinate of each signal transmission conductor 420 which connects the unit cells 300 in the horizontal direction and extends up to the edge is set to a Y-axis coordinate as a second axis coordinate, and the coordinate of each signal transmission conductor 430 which connects the unit cells 300 in one diagonal direction and extends up to the edge is set to a Z-axis coordinate as a third axis coordinate. A process of grasping the touch point of the user through the unit cells 300 connected by the signal transmission conductors 400 (410, 420, and 430) is performed by equally applying pulse train signals to all of the X-axis signal transmission conductors 410 and then sequentially touching the respective Y-axis and Z-axis signal transmission conductors 420 and 430 one by one by a user to detect touch position signals generated thereby. Next, in the same manner, pulse train signals are applied to the Y-axis signal transmission conductors 420, and then touch position signals are detected by sequentially touching the respective X-axis and Z-axis signal transmission conductors 410 and 430 one by one. Touch position coordinates are obtained by combination of X- and Y-axis position signals among X-, Y-, and Z-axis position signals obtained through the above processes. Here, the coordinate of each unit cell 300 may be grasped if the X and Y coordinates are obtained. In this case, the Z-axis coordinate is used to remove a virtual signal caused when two or more touches are generated. If virtual identification is difficult by the Z-axis coordinate alone due to touches of many users, it may also be possible to reinforce a virtual signal removal function by further adding one signal transmission conductor defining a separate W-axis.
As shown in
The three signal transmission conductors 400 meet at the central point of the unit cell 300. The transparent insulation films 500 are formed such that the three signal transmission conductors 400 are insulated from each other at the central point of the unit cell 300 at which the signal transmission conductors 400 overlap. That is, the transparent insulation films 500 are respectively applied between the X- and Y-axis signal transmission conductors 410 and 420 and between the Y- and Z-axis signal transmission conductors 420 and 430 such that the three conductors may be electrically isolated from each other.
The unit cell 300 shown in
The signal transmission conductors 400 (410, 420, and 430) connecting the unit cell pads 310, 320, 330, and 331 serve to transfer the touch signals generated by the unit cell pads to the external control board. The signal transmission conductors 400 (410, 420, and 430) are not produced in a transparent form. Accordingly, when each of the signal transmission conductors has a thick width, there is a problem in that the signal transmission conductor is visible by a user' eyes to cover the screen (pad) disposed below thereof Thus, each of signal transmission conductors 400 (410, 420, and 430) is preferably formed in a very thin form using very high conductivity so as not to be visible by a user' eyes without using a magnifying glass. In the embodiment of the present invention, each of signal transmission conductors 400 (410, 420, and 430) is formed to have a width of 20 μm or less, thereby obtaining transparency so as not to be identified by a user's naked eye.
The unit cells 300 configured of the combination of the plural unit cell pads 310, 320, 330, and 331 are thinly applied and arranged on one surface of the transparent base plate 100. The unit cells 300 have transparency and conductivity and are formed via a simply printed method in the atmosphere instead of a difficult process such as vacuum deposition. In the embodiment of the present invention, each of the unit cells 300 is printed and applied on one surface of the transparent base plate 100 by a printed method such as a silk screen method. The unit cell 300 is made of a material such as a polymeric material (for example, PEDOT/PSS) having transparency and conductivity.
Hereinafter, a description will be given of operation grasping a touch position of a user through the capacitive touch sensor having the above configurations.
Meanwhile,
As described above, in a case in which only one touch point is present, the touch point may be grasped when the X- and Y-axis coordinate positions of the touched unit cell 300 are sensed. However, when two or more touch points are present, a virtual point may be generated. For example, when two coordinates of x1 and x2 on the X-axis and two coordinates of y1 and y2 on the Y-axis are sensed, four points obtained by (x1, y1), (x1, y2), (x2, y1), and (x2, y2) which are combination of the coordinates are produced. Among them, the two points are actual touch points and the remaining two points are virtual points. This is because the coordinate of one point is not identified as a set of x and y coordinates such as (x1, y1) and (x2, y2). In other words, since the X-axis coordinate and the Y-axis coordinate are sequentially identified and are then produced through signal processing, a set of coordinates is not obtained. When the touch point is three, nine points obtained by combination of x1, x2, x3 coordinates and y1, y2, y3 coordinates are produced. The number of the coordinate combinations is typically defined by the square of the number of the touch points. Among these points, the actual touch point and the virtual point have to be identified. However, since identification of the actual touch point and the virtual point using only information of the X- and Y-axis coordinates is logically impossible, the present invention produces a third coordinate, namely, Z-axis information and utilizes the same, thereby allowing the actual touch point and the virtual point to be identified.
As shown in
Steps S310 and S320: first, as illustrated in
Step S330: after a set of X- and Y-axis coordinates capable of being generated via the above process is created, a Z-axis coordinate passing through the created set of X- and Y-axis coordinates is produced. The Z-axis coordinate passing through the set of X- and Y-axis coordinates may be calculated according to the relation of the predetermined X-, Y-, and Z-axes.
Step S340: the Z-axis coordinates measured in step S310 are searched and are then compared with the Z-axis coordinate produced in step S330.
Steps S350, S360, and S370: if a Z-axis coordinate of a case in which the Z-axis coordinate produced from the set of X- and Y-axis coordinates coincides with the measured Z-axis coordinate is present (S350), the set of X- and Y-axis coordinates is identified as an actual touch point (S360). If a Z-axis coordinate of a case in which the Z-axis coordinate produced from the set of X- and Y-axis coordinates coincides with the measured Z-axis coordinate is not present, the set of X- and Y-axis coordinates is identified as a virtual point (S370).
As described above, it may be possible to recognize and grasp the plural touch points of the user by means of using the Z-axis coordinate together with the X- and Y-axis coordinates. However, if the number of the touch points is increased, an identification process is further complicated and various problems may be caused in that the plural points have the same Z-axis coordinate.
In a case in which the touch point may not be grasped only using the X- and Y-axis coordinates, it may be possible to further increase identification performance in a complicated case by adding a separate W-axis as an inclined axis to the X-, Y-, and Z-axes.
As shown in
Similarly to being illustrated in
Meanwhile, as shown in
The unit cell 300 shown in
In the present embodiment, a virtual touch point may be removed by adding the Z- and W-axes to the X- and Y-axes in order to identify multiple touch points of the user. Meanwhile, when the touch pad to which the touch sensor is applied has a relative small size and requires only a simply function, the touch point of the user may be detected using the X- and Y-axes alone without addition of the separate Z- and W-axes.
As shown in
In the touch sensor, the transparent electrode thin film 200 is formed by arrangement of the plural unit cells 300. The plural unit cells 300 is continuously connected adjacent to each other in the vertical and horizontal directions without being spaced apart from each other, thereby forming the transparent electrode thin film 200. In addition, the signal transmission conductors 400 electrically connecting the unit cells 300 are formed with only the X-axis conductor 410 as the first axis and the Y-axis conductor 420 as the second axis, and the Z- and W-axis conductors in the diagonal direction, which are present in the embodiments of
As shown in
As shown in
Meanwhile, although the unit cells 300 and the unit cell pads 310, 311, 320, and 321 have been described to be formed in a polygonal shape in
As shown in
Although the transparent electrode thin films formed of two X- and Y-axes shown in
As shown in
As shown in
In a case of forming the transparent electrode thin films on the transparent base plates by a method in
In the capacitive touch sensor according to the present invention which may be changed in various shapes, the transparent electrode thin film 200 on which the plural unit cells 30 are arranged is formed on one surface of the transparent non-conductive base plate 100. When the user touches the other surface of the transparent base plate 100, the touch sensor may detect the signals generated from the unit cells 300 by mutual capacitance and grasp the touch position.
Various embodiments have been described in the best mode for carrying out the invention. Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| KR10 2011-004649 | May 2011 | KR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/KR2011/005199 | 7/14/2011 | WO | 00 | 11/15/2013 |
