JP2011113481A - Coordinate input panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coordinate input panel which can use a single conductive material not needing mixture or the like as a material of a resistive peripheral electrode other than a surface resistor and has such a pattern of the resistive peripheral electrode that a resistance value of the resistive peripheral electrode can be easily designed. <P>SOLUTION: Each side of the resistive peripheral electrode is constituted of an aggregate of a plurality of elongate linear conductive segments formed on the surface resistor with spaces therebetween and partial regions forming the spaces of the surface resistor. The linear conductive segments are so inclined with respect to each side of the resistive peripheral electrode that linear ends facing the inside of a coordinate input area in each side of the resistive peripheral electrode are located nearer to the center of the side and linear ends facing the outside of the coordinate input area in each side of the resistive peripheral electrode are located nearer to both ends of the side. The conductive segments adjacent to each other are disposed so that they may be parallel with each other with the same inclinations and have linear portions put one over the other at least partially with spaces of the surface resistor therebetween. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a coordinate input panel of a coordinate input system that detects a touch position with a finger or a coordinate indicator.

FIG. 5 shows a conventional coordinate input panel 1 having a rectangular coordinate input region 8, and a resistive surrounding surrounding the surface resistor 2 so as to be electrically connected to the uniform surface resistor 2. An electrode 3 is disposed, and detection electrodes 4, 5, 6, and 7 are provided at four vertices. The detection electrodes 4, 5, 6, and 7 are electrically connected to the resistive surrounding electrode 3. The coordinate input area 8 is on the surface resistor 2 and inside the resistive surrounding electrode 3.
As a coordinate detection method of the coordinate input system using the coordinate input panel 1, a signal is transmitted from a coordinate indicator (hereinafter referred to as an input pen) such that the coordinate input panel 1 is a receiving side, and capacitive coupling or A method in which the surface resistor 2 receives a signal transmitted from the input pen through direct contact, and furthermore, the position of the point indicated by a finger or a conductor is input by oscillating the entire surface resistor 2 with voltage. A method of detecting on the panel side, and a method of receiving signals with an input pen by driving each part of the surface resistor 2 such that the direction of signal transmission is opposite and the coordinate input panel 1 is the transmitting side There is.

  When the coordinate input panel 1 is the receiving side, it is known to measure the current value distributed to the four vertices (4, 5, 6, and 7) of the current that enters and exits one point of the surface resistor 2. (See Japanese Patent No. 3237629 (Patent Document 1)). On the other hand, when the coordinate input panel 1 is the transmitting side, a potential gradient is applied to the surface resistor 2 from the outside through the detection electrodes 4, 5, 6, and 7, and the voltage level at the designated coordinate point is detected by the input pen. Things are known. The coordinates of the position indicated by the finger or the input pen are calculated using the distribution value of the current flowing in and out of the surface resistor 2 to the four vertices or the voltage measured with the input pen when driving the four vertices. As a coordinate detection method when the coordinate input area 8 of the coordinate input panel 1 is not a rectangle but a general polygon, for example, Japanese Patent Application No. 2008-251905 (Patent Document 2) by the same applicant exists. .

  In the coordinate input system described above, it is necessary to make the potential distribution or current distribution generated in the coordinate input area 8 uniform in order to accurately detect the position of the point where the finger or the conductor is close or in contact. It is known that when the resistance value per side of the resistive surrounding electrode 3 or the resistivity per length is high, the position detection of the contact point is shifted. For this reason, it is preferable that the resistance value of the resistive surrounding electrode 3 is as low as possible with respect to the resistance value of the surface resistor 2. However, if the resistance value of the resistive surrounding electrode 3 is set too low, the power consumption increases or the drive current that gives a potential gradient is large, and a DC or AC potential gradient is forcibly created in the surface resistor 2. Inconvenience in circuit control such as failure to perform the operation occurs. On the other hand, if the resistance value of the surface resistor 2 is increased, the resistance value of the resistive surrounding electrode 3 can be relatively lowered. However, if the resistance value of the surface resistor 2 is increased, the resistance value is weakened by noise. There was a problem. Therefore, it is desirable that the resistive surrounding electrode 3 has a resistance value controlled to an appropriate value.

  In order to set the resistance value of the resistive surrounding electrode 3 to a predetermined value, for example, there is a method in which a material having a certain resistivity is applied linearly to form each side of the resistive surrounding electrode 3. . However, if silver is used as the material to be applied, for example, since the resistivity of silver is low, each side of the resistive surrounding electrode 3 must have a very narrow width in order to obtain an appropriate resistance value. The formation method is difficult. In addition, silver mixed with carbon and increased resistance is suitable for forming peripheral electrodes, but it is necessary to mix different materials and it is difficult to maintain a stable resistance in the manufacturing process. It is.

  Another method for forming the resistive surrounding electrode 3 is to form a discontinuous pattern using a segment of a conductive material having a low resistance (for example, silver ink), and the resistance of the surface resistor 2 existing in the gap, There is one that realizes a predetermined resistance value (see, for example, JP 2005-530274 A (Patent Document 3)). In these methods, the arrangement pattern of the conductive segments for making the potential distribution or current distribution uniform is often complicated, and it is sometimes difficult to design the resistance value of the resistive surrounding electrode 3.

Japanese Patent No. 3237629 Japanese Patent Application No. 2008-251905 JP 2005-530274 Gazette

  The present invention has been made in consideration of such points, and a single conductive material that does not need to be mixed can be used as a material for the resistive surrounding electrode other than the sheet resistor. It is an object of the present invention to provide a coordinate input panel having a pattern of resistive surrounding electrodes so that the resistance value can be easily designed.

  According to the present invention, a resistive resistive electrode having a polygonal shape with each side being a straight line is provided on a continuous surface resistor so that all sides are in electrical contact with the surface resistor. A coordinate input panel in which the inside of the peripheral electrode is a coordinate input region, and each side of the polygonal resistive peripheral electrode has a plurality of elongated linear shapes formed on the surface resistor with gaps therebetween. It consists of an assembly of a conductive segment and a partial region of the surface resistor that forms the gap, and the linear conductive segment is inclined with respect to each side of the resistive surrounding electrode, and its inclination is The end of the straight line facing the inside of the coordinate input area of each side of the resistive surrounding electrode is located on the center side of each side, and the end of the straight line facing the outside of the coordinate input area is on each side of each side Conductive segments adjacent to each other. Are arranged so as to be parallel to each other with the same inclination, and so as to at least partly overlap the linear portion with the gap of the surface resistor interposed therebetween, and are closest to the center of each side of the resistive surrounding electrode. A coordinate input panel having a pattern formed by connecting the ends of two conductive segments is proposed.

  According to the coordinate input panel of the present invention, since a single conductive material can be used as the material of the resistive surrounding electrode, the resistance value of the resistive surrounding electrode can be stabilized, and the yield in the manufacturing process can be stabilized. Can be raised. In addition, if low resistance silver is used as the material for the resistive surrounding electrode, the same material as the sensing electrode can be used, so the sensing electrode and the resistive surrounding electrode can be formed simultaneously by printing or the like. Costs can be reduced as compared with separate formation.

  In addition, the resistive surrounding electrode pattern is slanted and partially overlaps each other, so that each side of the resistive surrounding electrode is connected in series with the resistance formed by the gap between adjacent conductive segments Therefore, the resistance value can be easily designed.

  Furthermore, when the difference between the low resistance value of the resistive surrounding electrode and the high resistance value of the surface resistor is not ideal, the result of detecting the position where the finger or the conductor is close or in contact may be distorted, The distortion can be reduced by adjusting the distribution of the resistance value in each side of the resistive surrounding electrode, but by changing the overlapping length of the adjacent conductive segments, the resistance value can be reduced. The distribution can be easily adjusted.

Schematic diagram of coordinate input panel Configuration diagram showing an example of a coordinate input system Partial enlarged view of resistive surrounding electrode Conceptual diagram of resistive surrounding electrode Conventional rectangular coordinate input panel

Hereinafter, preferred embodiments of a coordinate input panel according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic view of a polygonal coordinate input panel 11 according to the present invention (FIG. 1 shows an example of a quadrangle). The coordinate input panel 11 forms a uniform surface resistor 12 on a base material (not shown) and is a resistive peripheral electrode surrounding the surface resistor 12 so as to be electrically connected to the surface resistor 12. 13, and detection electrodes 14, 15, 16, and 17 are formed at the respective vertices. The resistive surrounding electrode 13 is composed of an assembly of a plurality of elongated linear conductive segments and a portion of the sheet resistor 12 that forms a gap between adjacent conductive segments. The coordinate input area 18 indicates an area inside the resistive surrounding electrode 13.

  For example, soda glass can be used as the substrate, but the material is not particularly limited, and any glass material or a transparent resin material such as an acrylic resin or a polyethylene resin can be used. Depending on the application, an opaque insulating substrate may be used. As the surface resistor 12, an ITO (indium oxide) film formed by sputtering, a tin oxide film formed by CVD, or the like can be used.

The conductive segment constituting the resistive surrounding electrode 13 can be formed by printing and baking using a low-resistance conductive ink such as silver. The detection electrodes 14 to 17 at the respective apexes are for connecting lead wires, and are formed by printing and baking a solderable conductive ink. As the conductive ink for forming the detection electrodes 14 to 17, the same conductive ink as that for forming the conductive segments constituting the resistive surrounding electrode 13 can be used. The conductive segments constituting the peripheral electrode 13 can be formed by printing and baking in a single process.
Further, although not shown, when capacitive coupling is used for interaction between the finger or the coordinate indicator and the surface resistor 12, a transparent insulating substrate is provided on the surface resistor 12 in order to protect the surface resistor 12. May be coated.

  FIG. 2 is a block diagram showing an example of a coordinate input system using the coordinate input panel 11 according to the present invention, in which the input panel is the receiving side. 2 is a configuration diagram of a coordinate input system that detects a position coordinate indicated by a finger 21 in a coordinate input area 18 of a coordinate input panel 11. FIG. As described above, the surface of the surface resistor 12 is insulated so that the finger 21 does not touch the surface resistor 12 directly, thereby transmitting a signal by capacitive coupling between the finger 21 and the surface resistor 12. Alternatively, the signal may be transmitted by direct electrical contact between the finger 21 and the surface resistor 12 without being insulated. Here, the case where the surface of the surface resistor 12 is covered with a transparent insulating base material for insulation treatment will be described. Polygonal resistive surrounding electrodes 13 each having a straight line are formed on a uniform sheet resistor 12, and the inside of the resistive surrounding electrode 13 is used as a coordinate input area 18 (FIG. 2 shows an example of a quadrangular shape). Showing). On the resistive surrounding electrode 13, the positions corresponding to the vertices of the polygonal coordinate input region 18 are set as detection electrodes 14 to 17, and lead lines 22, 23, 24, and 25 are respectively connected to the detection electrodes 14 to 17. Furthermore, the lead wires 22 to 25 are connected to an oscillating voltage application circuit 27 in the analog signal processing unit 26.

  When detecting the coordinates, the oscillating voltage generator 28 serving as an AC signal source applies an oscillating voltage to the oscillating voltage applying circuit 27, and the oscillating voltage applying circuit 27 oscillates the corresponding detection electrodes 14 to 17 with low impedance. In addition, the current flowing from the detection electrode to the analog multiplexer 29 is output. As a simple example, a transistor base is vibrated by an AC signal, an emitter is connected to a detection electrode, and a current is output from a collector.

The vibration resistance generator 28 serving as an AC signal source causes voltage oscillation of the entire surface resistor 12. As is known in the art, the human body has a grounding effect on the AC signal. When the human finger 21 contacts or approaches the surface resistor 12, the surface resistor is passed through the fingertip by capacitive coupling. AC signal current flows between The detection electrodes 14 to 17 are connected to an A / D converter (analog / digital converter) 30 through an analog multiplexer 29, and a voltage proportional to the current flowing through each detection electrode is applied to the A / D converter 30. The current value flowing from the fingertip through the surface resistor 12 and distributed to the detection electrodes 14 to 17 can be obtained as a voltage value as a digital value. The CPU 31 sequentially switches the analog multiplexer 29 (not shown), inputs the digital value output from the A / D converter 30, and calculates the coordinates of the pointing position of the finger 21 or the input pen. In order to calculate the coordinates of the indicated position, for example, an equation as disclosed in Japanese Patent No. 3237629 (Patent Document 1) can be used. CPU31 outputs the calculated coordinate and a coordinate is utilized by the apparatus of a back | latter stage.
Further, when a signal is transmitted from the input pen, measurement can be performed in the same manner.

  Next, the resistive surrounding electrode 13 will be described. FIG. 3 shows a partially enlarged view of the resistive surrounding electrode 13. The left half of the upper side of the four sides of the rectangular coordinate input panel 11 is shown together with the detection electrode 14. In the present embodiment, half of one side is composed of seven linear conductive segments 41a to 41g. The plurality of conductive segments 41 a to 41 g are arranged so that the straight line of the conductive segment is inclined with respect to the straight line that is the side of the resistive surrounding electrode 13. The slope is lowered to the right in the left half of the upper side shown in FIG. 3, and the slopes of all the conductive segments in the region are made equal. In the right half, the slope is raised to the right. The arrangement pattern of the conductive segments is preferably symmetric with respect to the center of each side of the resistive surrounding electrode 13. However, the arrangement pattern need not be the same between the sides.

The end of the side of the resistive surrounding electrode 13, that is, the conductive segment 41 a closest to the detection electrode 14 is connected to the detection electrode 14. On the other hand, the conductive segment 41g closest to the center of the side is connected to the conductive segment closest to the center of the side among the conductive segments in the right half of the upper side having a symmetrical arrangement with respect to the center of the side.
In addition, all the conductive segments are arranged so that at least the adjacent conductive segments arranged in parallel and the straight lines of the conductive segments partially overlap. The conductive segment 41a overlaps with the conductive segment 41b, the conductive segment 41g overlaps with the conductive segment 41f, and the conductive segments 41b to 41f respectively overlap with the conductive segments on both sides. To.

  If the number of the conductive segments constituting one side is large, it is possible to reduce the distortion of the calculation result of the coordinates of the indicated position in the coordinate input area 18 to the middle of the resistive surrounding electrode 13. The distortion occurs for the following reason. As an example, the conductive segment 41b will be described. The current flows from the inside of the coordinate input region 18 into the conductive segment 41b with respect to the region excluding the portion of the conductive segment 41b that faces the coordinate input region 18 and is hidden by overlapping the conductive segment 41a. It is. Since the resistance of the conductive segment 41b is low, the position of the region into which the current of the conductive segment 41b flows cannot be identified by itself regardless of where the current flows. If the position indicated by the finger 21 in the coordinate input area 18 is sufficiently away from the resistive surrounding electrode 13, the current flows with a two-dimensional distribution, so that not only the conductive segment 41b but also both sides. Since the current flows into the conductive segments including the conductive segments 41a and 41c, the distortion of the current flow is generally reduced, and an accurate indication position can be calculated. However, when a position extremely close to the conductive segment 41b in the coordinate input area 18 is indicated, most of the current flows into the conductive segment 41b, so that the calculation result of the coordinates of the indicated position is distorted. To do. When the number of conductive segments constituting one side is increased, such distortion can be reduced.

  On the other hand, when the number of conductive segments is large, the total resistance value constituted by the gaps tends to increase. Therefore, it is necessary to adjust the resistance value per side of the resistive surrounding electrode 13, that is, the resistance value between adjacent detection electrodes, by adjusting the number of conductive segments, the gap, the overlapping length, and the like. .

  FIG. 4 is a conceptual diagram for explaining a partially enlarged view of the resistive surrounding electrode 13 shown in FIG. In FIG. 4, the conductive segments 41 a to 41 g are shown by straight lines having no thickness, and the gaps are shown wide to clarify the arrangement pattern. Of the surface resistor 12, the gap portion between the conductive segments 41a to 41g arranged side by side in parallel shown by the mesh 43 in FIG. 4A contributes to the resistance value per side of the resistive surrounding electrode 13. To do. More precisely, the two-dimensional resistance distribution due to the partial overlap of the conductive segments should be considered, but the length of the overlap is larger than the width of the gap. Even if the area other than 43 is ignored, there is no practical problem.

  The portion of the surface resistor 12 indicated by the mesh 43 in FIG. 4A is equivalent to the resistance of the gap between the adjacent conductive segments 41a to 41g arranged in parallel in FIG. 4B. It can express as resistance 42A-42F shown. That is, the resistive surrounding electrode 13 can be regarded as one in which these equivalent resistors 42A to 42F are connected in series. And each resistance value of equivalent resistance 42A-42F is based on the resistance value of the surface resistor 12, the distance d of each gap | interval of the adjacent conductive segments 41a-41g arranged in parallel, and the overlapping length w. Can be sought.

  The resistance value of the surface resistor 12 is generally represented by sheet resistance. If the sheet resistance of the surface resistor 12 is ρ (Ω / □), for example, the resistance value of the equivalent resistor 42F can be calculated by the equation ρ × d / w (Ω). If the resistance values of the equivalent resistances 42A to 42F are calculated using the respective gaps and the respective overlapping lengths, the resistance value per half of one side of the resistive surrounding electrode 13 is the sum of them. Thus, the resistance value per side of the resistive surrounding electrode 13 can be obtained as twice as long as the conductive segment arrangement pattern is symmetrical.

  The distance d of the gap may be constant in the resistive surrounding electrode 13 or may be changed depending on the location. The overlapping length w is the same when the conductive segments having the same length are arranged, but w may be changed by changing the length of the conductive segments. Especially in the vicinity of the edge of the side, if the conductive segments have the same length, depending on how the detection electrode 14 is formed, it may interfere with the detection electrode 14. May be. This length adjustment is also preferable from the viewpoint of reducing the distortion of the coordinate calculation result described below.

  In consideration of the accuracy of the calculation result of the coordinates of the indicated position, the resistance value per side of the resistive surrounding electrode 13 is preferably as low as possible. It must have a certain resistance value. Therefore, distortion resulting from the calculation of coordinates occurs. This distortion occurs across the entire area of the coordinate input area 18, unlike the local one that occurs just before the resistive surrounding electrode 13 due to the number of conductive segments. On the other hand, this strain can be reduced by distributing the resistance distribution inside each side of the resistive surrounding electrode 13 so that the resistance distribution is low at the center of the side and high resistance near the end of the side. It is known that it can be done.

  For this reason, as shown in FIG. 4, when the length of the conductive segment is shortened as it approaches the end of the side of the resistive surrounding electrode 13, the shorter the length of the conductive segment, the more closely arranged in parallel. As the overlapping length w of adjacent conductive segments becomes shorter and the overlapping length w becomes shorter, the resistance value of the equivalent resistance in that region becomes higher. Therefore, it is possible to realize a desirable resistance distribution in which the resistance is higher in the vicinity of the edge of the side than in the center of the side.

  Hereinafter, the present invention will be described with reference to examples and comparative examples. The present invention is not limited to the following examples, and includes various modifications within the technical scope of the present invention.

Example 1
The coordinate input panel 11 was created as follows. As a glass substrate, soda glass (thickness 3 mm) cut into a size of about 469 × 375 mm is used, and an ITO (indium oxide) film is formed on the surface of the glass substrate by sputtering. A resistor 12 was obtained. Next, the conductive segments of the resistive surrounding electrode 13 and the detection electrodes 14 to 17 were formed by screen-printing and heat-curing silver paste LS-504 (resin binder) manufactured by Asahi Chemical Laboratory. . At this time, the size of the coordinate input area 18 was approximately 450 × 350 mm, the thickness of the conductive segments 41a to 41g was constant at 0.5 mm, and the gap d was constant at 0.5 mm. Further, regarding the overlapping length w of the conductive segments 41a to 41g, for both the long side and the short side, for each of the equivalent resistances 42A to 42F, 42A is 30 mm, 42B is 45 mm, 42C is 65 mm, 42D is 85 mm, 42E and 42F were 100 mm. Thereby, each side of the resistive surrounding electrode 13 was able to set the resistance value per side to 50Ω.

  Further, a transparent insulating base material was formed on the surface resistor 12. In order to form a transparent insulating substrate, a glass paste was printed on the surface resistor 12 and the resistive surrounding electrode 13, heat treated to melt the powdered glass, and sintered. Finally, the lead wires 22 to 25 were connected to the detection electrodes 14 to 17 by soldering. At this time, the sheet resistance of the surface resistor 12 was set to 500Ω / □.

The coordinate input panel 11 created in this way was connected to the hardware created as shown in the block diagram of FIG. However, coordinate data output from the CPU 31 is taken into a personal computer by serial communication.
When the coordinate input panel 11 was evaluated using this coordinate input system, it was confirmed that the coordinates of the indicated position can be calculated with sufficiently small distortion.

DESCRIPTION OF SYMBOLS 1 Coordinate input panel 2 Surface resistor 3 Resistive surrounding electrode 4, 5, 6, 7 Detection electrode 8 Coordinate input area 11 Coordinate input panel 12 Surface resistor 13 Resistive surrounding electrode 14, 15, 16, 17 Detection electrode 18 Coordinate Input area 21 Finger 22, 23, 24, 25 Lead line 26 Analog signal processing unit 27 Vibration voltage application circuit 28 Vibration voltage generator 29 Analog multiplexer 30 A / D converter 31 CPU
41a, 41b, 41c, 41d, 41e, 41f, 41g Conductive segment 42A, 42B, 42C, 42D, 42E, 42F Equivalent resistance 43 Gap between adjacent conductive segments in parallel

Claims (1)

A polygonal resistive peripheral electrode having a straight line on each side is provided on a single surface resistor so that all sides are in electrical contact with the surface resistor. A coordinate input panel having a coordinate input region, each side of the polygonal resistive surrounding electrode includes a plurality of elongated linear conductive segments formed on the surface resistor with a gap therebetween. The linear conductive segment is slanted with respect to each side of the resistive surrounding electrode, and its inclination is defined by the resistive surrounding electrode. The end of the straight line facing the inside of the coordinate input area of each side is located on the center side of each side, and the end of the straight line facing the outside of the coordinate input area is located on each side of each side And conductive segments adjacent to each other are Two conductors that are parallel to each other with the same inclination and that are at least partially overlapped with the gap between the surface resistors being closest to the center of each side of the resistive surrounding electrode. Coordinate input panel characterized by having a pattern formed by connecting the ends of sex segments.