JP5529172B2 - Surface capacity by area gesture - Google Patents

Description

Cross-Citation for Related Applications This document is a provisional patent application agent reference number 4519. filed on March 6, 2009, with application number 61 / 158,281. CIRQ. By claiming priority over all of the subject matter contained in the PR issue and quoting this application, all of that subject matter is also included in the present application. This provisional patent application is a co-pending patent application No. 4455. filed on Nov. 20, 2009 with an application number of 12 / 592,283. CIRQ. It is a partial continuation application of NP.

The present invention relates generally to touchpads using surface capacitance technology. More specifically, the present invention is a new method for determining the position of one or more pointing objects on a surface capacitive touch panel.

  Capacitive touch screens are readily available for use in a variety of applications. As touch sensitive screens become more widespread and useful, technologies for realizing them are also being developed.

  A variety of different touch screen and touch pad technologies have emerged, including projection capacitance methods and surface capacitance methods. The projected capacitance method is currently required to perform a gesture that uses more than one finger or pointing object simultaneously on the surface.

  For example, FIG. 1 is a top view of an array of orthogonal electrodes 6, such as a plurality of X (2) and Y (4) electrodes, as produced by Cirque Corporation®. Often used in screen technology. However, the projected capacitance method generally requires a more complicated process to etch the electrode pattern onto the conductive surface and is therefore more costly to implement than the surface capacitance method.

  An example of surface capacitance technology is shown in FIG. In such a surface cap panel, a solid sheet of conductive material 16 is disposed on an insulating substrate 18 such as glass, and sensors 12 are disposed at each corner. In the conventional method of measuring the position of the pointing object 14, that is, the “contact position” on the surface capacitive touch panel 10, an AC signal is applied to all four corners of the conductive layer 16 of the touch panel. The conductive layer 16 can be made of, for example, indium tin oxide (ITO).

  To make the touch panel 10, the surface of the glass substrate 18 is filled, i.e., covered, with a substantially planar layer of resistive ITO material that forms a sheet resistance. A dielectric is then deposited over the ITO conductive material.

  After applying the AC signal to the conductive ITO material 16, in the next step, the contact position is measured trigonometrically using the current passing through each corner. It is common to apply either a sine wave or a square wave.

  When an object such as a finger 14 contacts the surface of the touch panel 10, a capacitor is formed between the ITO surface 16 and the fingertip 14. Its capacitance value is very small, typically about 50 pF. Therefore, the amount of charge or current to be measured flowing into each corner 12 of the panel is very small. Since the current is very small, this system is very susceptible to stray capacitance. For this reason, the accuracy of the touch panel often becomes a problem.

  With these two different touch technologies in mind, software applications in portable or stationary electronics, such as computers, smart phones, and any other device that can use a touch interface, “pinch” Currently starting to use a second contact point (a contact point like a finger and thumb or two fingers) to support gestures such as “pinch and zoom”, panning, rotation, etc. Is observed. Other applications may use a third simultaneous contact for “next and previous” gestures, or a fourth simultaneous contact for switching between applications.

  A multi-finger gesture can also be performed using an “area gesture” as in the method taught by Cirque Corporation (registered trademark). Area gestures do not track a large number of contacts, but instead perform these area gestures by considering these multiple contacts as only one large object, and the multiple contacts may delimit the outer boundary of the large object. Just define it. Thus, a large number of contact points can be considered to have a height and a width.

  Operating system software and human interface device (HIG) standards have been modified to include these new gestures and methods for reporting multi-finger contact with touch sensitive surfaces.

  Suitable to be used to determine the outer boundary of large objects, as defined by Cirque Corporation®, to track more than one contact point or for multiple contact points Since there was no way, it was not possible to use cost-effective surface capacitive touch screens or touchpads (hereafter referred to as “surface cap panels”) to support multi-finger or area gestures. It was. In other words, it was not possible to determine the height and width of a large object.

  Thus, it would be an advantage over the current state of the art to be able to utilize area gestures defined by multiple contact points with the surface cap panel used as a touch screen and touchpad. With such a system, a new multi-contact technology could be used with simpler touch screen and touchpad technologies.

  In a first embodiment, the present invention is a surface capacitive touch sensitive surface (or “surface cap panel”) suitable for use in a touch screen or touchpad. The surface cap panel has a coating of a substantially planar conductive material on a non-conductive substrate and further covers the conductive material with a dielectric. Since the new current measurement circuit reduces the effect of stray capacitance on current measurement accuracy, a simple ratio equation can be used to determine the relative X and Y position of the object on the surface cap panel. By measuring the charge transfer rate in the measurement circuit in addition to the total charge transfer for each switching event, it is possible to locate the two objects on the surface cap panel. The charge transfer rate is used to determine the distance between two contact points on the surface cap panel. Then, by doubling the number of electrodes at the corners of the surface cap panel, height and width information regarding the distance between the two contact points can be determined.

  These and other objects, features, advantages and alternative aspects of the present invention will become apparent to those of ordinary skill in the art upon review of the following detailed description in conjunction with the accompanying drawings.

FIG. 1 is a perspective view of an X and Y electrode grid touchpad found in the prior art. FIG. 2 is a perspective view of a surface cap panel found in the prior art. FIG. 3 is a perspective view of a surface cap panel 10 made in accordance with the principles of the present invention. FIG. 4 is a circuit diagram showing how a current measurement circuit comprising a capacitor and a current measurement sensor is attached to the surface cap panel when there is one object. FIG. 5 is a top view of the surface cap panel in the first embodiment when used with the 8-wire method that can detect multiple objects. FIG. 6 is a circuit diagram showing how a current measurement circuit comprising two capacitors and two current measurement sensors is attached to the surface cap panel to detect a plurality of objects. FIG. 7 is a graph showing measurements taken during different time apertures. FIG. 8 is a top view of the surface cap panel showing in which corner the electrodes of the current measurement circuit are placed for eight different measurements that must be made to detect multiple objects. FIG. 9 is an alternative embodiment of a surface cap panel that can be used in the present invention.

  The present invention will now be discussed with reference to the drawings, which number the various elements of the invention, so as to enable those skilled in the art to make and use the invention. The following description is merely an example of the principle of the present invention, and it should be understood that the following claims should not be considered narrowed.

  FIG. 3 is a perspective view of a surface cap panel 10 made in accordance with the principles of the present invention. As disclosed in the aforementioned co-pending patent application, a new and novel approach to determining the position of an object on a touch panel is to charge a large capacitor and then this “flying capacitor” (flying capacitor) is attached to the two opposite ends of the touch panel 10. In the flying capacitor method of the present invention, this method measures the instantaneous and total currents induced in contact at the surface of the surface cap panel 20 when a constant voltage gradient is generated in one axial direction across the surface. To do. To perform this current measurement, a sensitive current measurement circuit 32 as shown in FIG. A flying capacitor 10 is used to charge the surface cap panel 10. Any charge removed from the surface cap panel 10 is measured by the current measurement circuit 32.

  By making the voltage gradient linear, the accuracy of the surface cap panel 10 in FIG. 3 can be improved. Therefore, in the first step, it is desirable, but not essential, to add a low resistance material around the edge of the touch panel 10 on the surface. The voltage gradient line 20 becomes closer and more linear from the upper edge 26 to the lower edge 28.

  In co-pending patent application No. 12 / 592,283, it is described that four measurements are required to determine the position of an object on the surface cap panel 10. The present invention expands the capability of the “flying cap” method of position determination by using what is called the “8-wire method”.

  FIG. 5 shows a surface cap panel 40 used in the 8-wire method. In this surface cap panel 40, gaps 42 are formed at each corner so that individual electrodes can be connected to the low resistance material at each end of the low resistance path. That is, the electrodes are connected at 50, 52, 54, 56, 58, 60, 62, and 64, which are 8 wires of the 8 wire method. These low resistance paths are isolated but are close enough to each other to form a constant voltage gradient, as in the co-pending patent application 4-wire method.

  The 8-wire method is performed by measuring the charge transfer rate in addition to the total charge transfer for each event. An event is defined as when a measurement is made. The charge transfer rate is used to determine the distance between two contact points on the surface cap panel 40. Accordingly, height and width information regarding the distance between the two contact points is determined by doubling the number of electrodes at the corners of the surface cap panel 40.

  FIG. 6 shows a modified version of the current measurement circuit 70 used in the 8-wire method. In FIG. 6, two flying capacitors 72 and 74 are attached to the surface cap panel 40 simultaneously. The simultaneous mounting of flying capacitors 72 and 74 allows for a relative measurement of the total resistance between the contact points and the horizontal and vertical low resistance paths on the surface cap panel 40.

  Specifically, the location of the contact point on the surface cap panel 40 is determined by measuring the current through multiple fingers and determining the effective Norton resistance of each parallel axis relative to the contact point.

  Norton resistance is obtained by performing sequential integration of current twice for each axis. The RC time constant can be determined by two measurements integrated over a long time frame and a short time frame. The location or proximity of the contact points to the edges is then determined by calculating the resistance between these contact points and the edges. The total integrated current (area under the curve below) is proportional to the finger capacity.

  A pinch gesture on one axis shown in FIG. 7 indicates a change in time constant when the contact points are moved away from each other. 2/1 is the before and after measurements when the fingers are first closed (2 and 4) and then spread (1 and 3). The greater the “short measurement” of 1 for 2, the greater the pinch on that axis.

  The present invention also extends the previous four-wire “flying cap” method by measuring a sudden change in capacitance and detecting a second contact point. When the position of the first contact point is fixed and the second contact point is moved, the midpoint position information is obtained. This information can then be used, for example, to provide information about the “rotation” gesture.

  The 8-wire method operates on the same principle as the co-pending patent application 4-wire method. This is because the individual electrodes are connected to the low resistance material at each end of these electrodes. The current induced in the low resistance material is many times greater than the current induced in a finger or other contact point on the surface cap panel.

  FIG. 8 is a block diagram of the surface cap panel 40 of the present invention. The corners of the surface cap panel are indicated by A, B, C, and D. F1 is a contact point arbitrarily selected for the first pointing object. F2 is a contact point arbitrarily selected for the second pointing object. O is marked as the midpoint between contact points F1 and F2.

  A reversely charged capacitor is continuously attached between the detection electrode and the drive electrode. Charges that leave the surface cap panel in a particular time frame are stored in a particular time frame. There are eight different combinations of electrode patterns and storage time frames. The total number of different measurements that must be made is eight. Eight measured values or eight combinations of electrodes and time frames are summarized in the “Repetition” column in Table 1.

The calculations that must be performed are as follows.
Z1 = M1 + M2
Z2 = M3 + M4
X = M3 / Z2
Y = M1 / Z1
Z = Z1 + Z3
Therefore, the calculation to analyze the pinching movement is defined as pinch = M1 / M5 + M2 / M6 + M3 / M7 + M4 / M8.

  The aspect ratio for the vertical and horizontal spacing of the contact points is determined by the average of the ratio of Ax and Ay for each measurement (from M1 to M8). That is, MRn = (Axn−Ayn) / (Axn + Ayn). Then, the aspect ratio = (MR1 / MR5 + MR2 / MR6 + MR3 / MR7 + MR4 / MR8) / 4.

  FIG. 9 is provided as an alternative embodiment of the surface cap panel 40. In this figure, small slots 80 are formed at each corner of the surface resistive material to further separate the electrodes 50, 52, 54, 56, 58, 60, 62, and 64. The slot 80 extends from the outer corner and projects to the active area of the surface cap panel 40 where contact is made.

  It goes without saying that the configuration described above is merely an example of application of the principle of the present invention. Numerous modifications and alternative arrangements may be devised by those skilled in the art without departing from the spirit and scope of the invention. The appended claims are intended to cover such modifications and arrangements.

Claims (9)

A method for measuring positions of a plurality of pointing objects on a surface capacitive touch panel (surface cap panel),
1) providing a surface cap panel comprising an insulating substrate, a resistive material disposed on the substrate, and a dielectric disposed on the resistive material;
2) the while the first capacitor is connected to the opposing two edges of the surface cap panel, connecting the second capacitor at both edges of different faces simultaneously, using a current measuring circuit, before Symbol surface cap panel while in different directions to the opposite side from, and measuring the current to the opposite side from one of said surface cap panel with a plurality of time frames different,
3) using the measurement values obtained in step 2) to measure the positions of the multiple pointing objects by trigonometry;
A method.   2. The method of claim 1, further comprising using a known voltage charge to determine how much current is leaking from the surface of the touch panel due to the presence of each of the multiple pointing objects. And supplying to the second capacitor.   The method of claim 1, further comprising performing current measurements in a first time frame group and a time frame group that is shorter than the first time frame. 4. The method of claim 3, further during the first time frame, as follows:
1) A drive electrode on the bottom side of the surface cap panel, and a detection electrode on the top side,
2) A drive electrode on the top side of the surface cap panel and a detection electrode on the bottom side;
3) A drive electrode on the left side of the surface cap panel and a detection electrode on the right side; and 4) A drive electrode on the right side of the surface cap panel and a detection electrode on the left side.
A method comprising the step of taking a measurement. 5. The method of claim 4, further during the short time frame:
1) A drive electrode on the bottom side of the surface cap panel, and a detection electrode on the top side,
2) A drive electrode on the top side of the surface cap panel and a detection electrode on the bottom side;
3) A drive electrode on the left side of the surface cap panel and a detection electrode on the right side; and 4) A drive electrode on the right side of the surface cap panel and a detection electrode on the left side.
A method comprising the step of taking a measurement.   The method of claim 1, further comprising using eight current measurements from claims 4 and 5 to determine the position of the plurality of pointing objects on the surface cap panel. Method. The method of claim 1, further comprising forming a linear voltage gradient from one side of the surface cap panel to the opposite side using the first and second capacitors.   The method of claim 1, further comprising refreshing the first capacitor and the second capacitor to a known voltage to maintain the voltage gradient across the surface cap panel.   2. The method of claim 1, further comprising: increasing the accuracy of the method of measuring the position of the plurality of indicating objects on the surface cap panel by only leaking the current to the plurality of indicating objects and the current measuring circuit. A method comprising a step of enhancing.

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