Proximity detection device

Abstract

To solve the following problem; as the number of couplings of electrodes is increased for obtaining sufficient sensitivity for detecting an approaching finger, a proximity detection distance can be secured while a region in which proximity detection is enabled is narrowed.SOLUTION: High-resolution proximity detection is enabled without narrowing a detection range even when the number of couplings of electrodes is increased to improve sensitivity by sequentially coupling the electrodes from an end of a touch panel having the electrodes and by sequentially coupling the electrodes while shifting them by a predetermined number of electrodes, so that some of the electrodes overlap each other, to form coupled electrodes when a predetermined number of couplings of electrode is reached to the maximum. It can be easily distinguished between the case where the end of the touch panel is touched and the case where a finger is close to a part which is little distant from the end.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] This application relates to a proximity detection device.

Background Art

[0002] In order to detect the position of a finger close to a touch panel (capacitive projection type) with high resolution, means is known in which a plurality of electrodes are sequentially combined while being shifted by an arbitrary number of electrode slides so that some of the electrodes overlap the electrodes with the number of electrode combinations (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the technique of Patent Document 1, in order to obtain sufficient sensitivity for detecting a proximity finger, when increasing the number of electrode combinations, although the proximity detection distance can be ensured, there is a problem that the proximity detection possible area becomes narrow. Further, when detecting the difference between proximity and contact, it may be difficult to distinguish between the case where the end of the touch panel is touched and the case where a finger is close to a portion slightly separated from the end from the respective detection values.

[0005] This application has been made to solve the above problems, and an object thereof is to provide a proximity detection device capable of performing proximity detection with high resolution without narrowing the detection range even when the sensitivity is increased by increasing the number of electrode combinations.

Means for Solving the Problems

[0006] The proximity detection device disclosed herein includes a touch panel having a plurality of electrodes whose capacitance changes upon proximity to and contact with an object to be detected, and a coupled electrode formed by sequentially increasing electrodes in a predetermined direction from the electrode at the edge of the touch panel. , most The electrode control unit, when the number of electrodes to be coupled reaches a maximum, repeatedly separates and couples the electrodes by a predetermined number of electrode slides so that some of the electrodes overlap, thereby maintaining the maximum number of electrodes coupled; a capacitance detection unit detects the capacitance of the end electrodes and the coupled electrodes; and a position calculation unit calculates the proximity or contact position of the object to be detected based on the capacitance detected by the capacitance detection unit. The maximum number of electrode connections is determined by calculating the magnitude of the change in capacitance detected by the capacitance detection unit, and is set as the number of connections at which the magnitude of the detected change in capacitance remains constant, depending on the size of the touch panel and the size of the electrodes. [Effects of the Invention]

[0007] According to the proximity detection device disclosed in this application, electrodes are sequentially coupled from the edge of the touch panel, and when the number of coupled electrodes reaches a predetermined maximum, the electrodes are sequentially separated and coupled in predetermined numbers of electrode slides so that some electrodes overlap, thereby enabling proximity detection with high resolution without narrowing the detection range, even when the number of coupled electrodes is increased to improve sensitivity. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram illustrates the coupling method of the electrodes of the touch panel of a proximity detection device according to a comparative example. [Figure 2] This diagram illustrates the coupling method of the electrodes of the touch panel of a proximity detection device according to a comparative example. [Figure 3] This diagram illustrates the coupling method of the electrodes of the touch panel of a proximity detection device according to a comparative example. [Figure 4] This figure shows a comparison of the magnitude of the change in capacitance of the proximity detection device in the comparative example, between contact and proximity. [Figure 5] This is a block diagram showing the overall configuration of the proximity detection device according to Embodiment 1. [Figure 6] This figure shows an example of the hardware of the control unit of the proximity detection device according to Embodiment 1. [Figure 7] This diagram illustrates the coupling and sliding method of electrodes on the touch panel of the proximity detection device according to Embodiment 1. [Figure 8] This is a flowchart illustrating the operation of the proximity detection device according to Embodiment 1. [Figure 9] This figure illustrates the maximum number of electrodes connected to the touch panel of the proximity detection device according to Embodiment 1. [Figure 10] This figure shows a comparison of the magnitude of the change in capacitance of the proximity detection device according to Embodiment 1 when it is in contact and when it is in proximity. [Modes for carrying out the invention]

[0009] Hereinafter, preferred embodiments of the proximity detection device according to the present application will be described with reference to the drawings. The same parts and components are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0010] Comparative example. Figures 1 and 2 show, as a comparative example, an example of electrode coupling method for the touch panel 1 of the proximity detection device.

[0011] In Figure 1, during the capacitance detection process by scanning from the edge of the touch panel 1, four electrodes x1 to x4 (number of electrode connections) are connected to form a coupled electrode. For the next detection process, one electrode (number of electrode slides) is slid to connect four electrodes x2 to x5 to form a coupled electrode. For the next detection process, one electrode is slid to connect four electrodes x3 to x6 to form a coupled electrode. Electrode coupling is performed sequentially in this manner.

[0012] Similarly, in the Y-axis direction, electrodes y1 to y3 are joined together to form a combined electrode, and for the next detection process, one electrode is slid to join electrodes y2 to y4, forming a combined electrode.

[0013] With such a configuration, the value of the capacitance can be increased by increasing the area of the coupling electrode. Further, by sliding the electrodes and coupling them so that they partially overlap, the number of coupling electrodes for detecting the capacitance can be increased compared to simply coupling adjacent electrodes, and the resolution when calculating the position can be improved. As a result, proximity detection can be performed with high resolution within the range shown in the detection region A of FIG. 1, and the sensitivity can be increased by increasing the number of couplings.

[0014] However, if the number of coupled electrodes is increased from 4 in the X-axis direction described in FIG. 1 to 5 electrodes x1 to x5 as shown in FIG. 2, and the number of coupled electrodes in the Y-axis direction is increased from 3 to 4 electrodes y1 to y4, the detection region where the resolution can be improved becomes region B, which is narrower than region A.

[0015] Furthermore, even when the number of coupled electrodes is 4 or 5, it becomes difficult to distinguish between the case where a finger, which is the object to be moved, touches the end C of the touch panel 1 indicated by the broken line in FIG. 3 and the case where the finger approaches the portion D indicated by the alternate long and short dash line approximately 20 mm inside from the end C. In FIG. 3, for ease of explanation, the description of the electrodes within the touch panel 1 is omitted.

[0016] For example, FIG. 4(a) is a graph showing the magnitude of the change in capacitance (contact detection value) when a finger touches the right and left ends C in the X-axis direction of the touch panel 1 with 5 coupled electrodes in the touch panel 1 shown in FIG. 3. FIG. 4(b) is a graph showing the magnitude of the change in capacitance (proximity detection value) when a finger is brought close to the portion D approximately 20 mm inside from both sides of the touch panel 1. The horizontal axis represents the order of the scan for energizing the coupled electrodes, and the vertical axis represents the magnitude of the change in capacitance. The change in the magnitude of the capacitance of each coupled electrode at the time of contact of the detection object at the left end is represented by series 1, and the change in the magnitude of the capacitance of each coupled electrode at the time of contact of the detection object at the right end is represented by series 2. In the case of this comparative example, the capacitance detection results in FIGS. 4(a) and 4(b) are the same, and it is difficult to distinguish between the contact and proximity of the finger to the touch panel 1 in the region described above.

[0017] Embodiment 1. For the above-described comparative example, in order to increase the sensitivity at the time of proximity, the configuration and operation of a proximity detection device that can detect proximity without reducing the area where proximity can be detected even when the number of electrodes to be coupled is increased will be described with reference to FIGS. 5 to 10.

[0018] FIG. 5 is a block diagram showing the overall configuration of the proximity detection device 10 according to Embodiment 1. An electrode control unit 12 and a capacitance detection unit 13 are connected to the electrodes x and y in the X-axis direction and the Y-axis direction of the touch panel 11, respectively. The electrode control unit 12 performs connection, separation, and sliding of each electrode, and an analog switch may be used.

[0019] The capacitance detection unit 13 detects the capacitance of the electrodes that have been connected, separated, or slid. The capacitance detection unit is composed of, for example, a resistor and a comparator, and calculates the charge and discharge time of the charge by counting the number of repetitions of charge and discharge in which the charge accumulated by the capacitance between the coupled electrodes and the detection object (such as a finger) reaches a predetermined voltage, and may detect the magnitude of the capacitance. Note that the present invention is not limited to this, and any configuration and method may be used as long as it is a method for measuring capacitance.

[0020] The control unit 14 controls the entire proximity detection device 10, controls the connection, separation, and sliding of the electrodes by outputting a control signal to the electrode control unit 12, calculates a change value of the capacitance from the capacitance detected by the capacitance detection unit 13 by energizing the electrodes or the coupled electrodes, outputs the change value to the position calculation unit 15, and calculates the position of the detection object. The control unit 14 and the position calculation unit 15 may be configured separately or integrally.

[0021] Figure 6 shows an example where microcontroller hardware is used in the control unit 14. It consists of a processor 100 and a storage device 200. Although not shown, the storage device 200 includes a volatile storage device such as random access memory and a non-volatile auxiliary storage device such as flash memory. Alternatively, a hard disk may be provided as an auxiliary storage device instead of flash memory. The processor 100 executes a program input from the storage device 200, instructing the electrode control unit 12 to connect, disconnect, and slide the connected electrode using control signals. By applying current to the electrode or connected electrode, the processor calculates the magnitude of the change in capacitance from the capacitance detected by the capacitance detection unit 13 and outputs it to the position calculation unit 15. In this case, the program is input from the auxiliary storage device to the processor 100 via the volatile storage device. The processor 100 may also output data such as calculation results to the volatile storage device of the storage device 200, or it may save the data to the auxiliary storage device via the volatile storage device.

[0022] Next, the operation of the proximity detection device 10 configured in this way will be explained using Figure 7. A scan is performed by sequentially energizing the electrodes, starting from the electrode at one end of the X-axis in the P direction (Step S1 in Figure 8). First, the number of electrodes coupled is sequentially increased as follows to detect capacitance (Step S2). Xs0 (scan 0) = electrode x1 Xs1 (Scan 1) = Electrode x1 + Electrode x2 Xs2 (Scan 2) = Electrode x1 + Electrode x2 + Electrode x3 Xs3 (Scan 3) = Electrode x1 + Electrode x2 + Electrode x3 + Electrode x4 Xs4 (scan 4)=electrode x1+electrode x2+electrode x3+electrode x4+electrode x5 In this embodiment, the number of energized coupling electrodes is increased one at a time, but it may be increased to any number, for example, 1, 3, 5... or 1, 2, 4, 5....

[0023] When the number of coupled electrodes reaches the maximum number of coupled electrodes (in this embodiment, the maximum number of coupled electrodes = 5) (step S3), the coupled electrodes are slid while maintaining the maximum number of coupled electrodes (step S4). That is, by separating electrode x1 and coupling electrode x6, one electrode (electrode slide number = 1) is slid, and the coupled electrode consisting of five electrodes from x2 to x6 is energized. Compared to the coupled electrode before the slide, electrodes x2 to x5 overlap. For the next detection process, by separating electrode x2 and coupling electrode x7, one electrode is slid, and the coupled electrode consisting of five electrodes from x3 to x7 is energized. Compared to the coupled electrode before the slide, electrodes x3 to x6 overlap. In this way, electrodes are sequentially slid, and the coupling and separation of electrodes are repeated while maintaining the maximum number of coupled electrodes. In this embodiment, the number of electrode slides is 1, but it is not limited to 1. Although the above explanation focused on the X-axis direction, capacitance can also be detected in the Y-axis direction by coupling electrodes and sliding the coupled electrodes. Furthermore, the number of coupled electrodes and the number of electrode slides may differ between the X-axis and Y-axis directions.

[0024] This type of electrode coupling makes it possible to perform proximity detection without narrowing the detection range, even when increasing the number of electrodes coupled to the touch panel 11. However, since the number of electrodes coupled at the edges is less than the maximum number of electrodes coupled, the sensitivity does not reach that obtained with the maximum number of electrodes coupled.

[0025] However, since capacitance detection is easier when touching the tip of a moving object, such as a finger, compared to close proximity, the same level of sensitivity as when touching a close-proximity object is not required, and a smaller number of connections at the tip is acceptable.

[0026] In this embodiment, the maximum number of electrode connections is set to 5. However, as shown in Figure 9, the change in capacitance may be detected in advance by setting a constant proximity distance from one end of the X-axis of the touch panel 11 to the other, and placing detection targets (inspection rod, finger, etc.) at equal intervals. The maximum number of electrode connections required to obtain a region E where stable detection is possible can then be calculated and set. The maximum number of electrode connections will vary depending on the size of the touch panel, the size of the electrodes, etc., but it is required to be a number of connections that results in a proximity detection value exceeding a predetermined threshold (proximity detection threshold). In addition, another threshold (contact detection threshold) is set for proximity detection values ​​around both ends that do not reach the maximum number of electrode connections, and the position of the detection target, such as a finger, is detected by proximity detection values ​​greater than the threshold.

[0027] In Figure 9, due to the characteristics of the scan, there are parts where the linearity between the proximity position on the coordinate system and the detected position in the scan data does not match between the first and second halves of the proximity detection value coordinate system, or parts where the proximity detection threshold and contact detection threshold cannot be handled at a constant value due to a decrease in the detected value. These will be corrected according to the measurement results.

[0028] As the electrode scan approaches the other end of the touch panel 11, at the position where the maximum predetermined number of bonded electrodes are separated (step S5), the sliding of the maximum number of bonded electrodes is completed, and the bonded electrodes are separated sequentially (step S6). In this embodiment, the number of bonded electrodes is separated and energized one by one with each scan, as described below. Xsn‐4=electrode xn‐4+electrode xn‐3+electrode xn‐2+electrode xn‐1+electrode xn Xsn‐3=electrode xn‐3+electrode xn‐2+electrode xn‐1+electrode xn Xsn‐2=electrode xn‐2+electrode xn‐1+electrode xn Xsn‐1=electrode xn‐1+electrode xn Xsn=electrode xn When the separation is complete, that is, when one electrode xn at the edge of the touch panel 11 is energized, the scan is terminated (step S7).

[0029] This makes it possible to perform proximity detection at the other end without narrowing the detection range. Furthermore, since capacitance detection is easier than proximity detection when detecting contact with the object, the same level of sensitivity as for proximity detection is not required, and fewer electrodes can be coupled. Similarly, by increasing or decreasing the number of coupled electrodes in the Y-axis direction, and by sliding the coupled electrodes with the maximum number of electrode couplings, the same effect as in the X-axis direction can be obtained.

[0030] Figure 10(a) shows the contact detection values ​​when a finger touches the edges C on both sides of the X-axis of the touch panel 11 after coupling and sliding the electrodes in this manner. The horizontal axis represents the electrodes that are energized during scanning, and the vertical axis represents the magnitude of the change in capacitance. Figure 10(b) shows the proximity detection values ​​when an object to be detected is brought approximately 20 mm inward from both sides of the touch panel 11. Series 1 shows the change in the magnitude of capacitance of each coupled electrode when an object to be detected comes into contact with the left edge, and Series 2 shows the change in the magnitude of capacitance of each coupled electrode when an object to be detected comes into contact with the right edge. From these graphs, a difference is created in the peak capacitance values ​​between contact and proximity, making it easy to distinguish between contact and proximity.

[0031] As described above, the configuration and operation of this embodiment enable proximity detection with high resolution without narrowing the detection range, even when the number of electrode connections is increased to raise sensitivity, and make it easy to distinguish between when the edge of the touch panel is touched and when a finger is close to a part slightly away from the edge.

[0032] Although this application describes exemplary embodiments, the various features, aspects, and functions described in the embodiments are not limited to the application of any particular embodiment, but can be applied individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the technology disclosed in this specification. These include, for example, modifications, additions, or omissions of at least one component.

[0033] The various aspects of this disclosure are summarized below as an appendix.

[0034] (Note 1) A touch panel having multiple electrodes whose capacitance changes upon proximity to and contact with an object to be detected. An electrode control unit that sequentially increases electrodes in a predetermined direction from the electrode at the edge of the touch panel to form coupled electrodes, and when the predetermined maximum number of coupled electrodes is reached, repeatedly separates and combines the electrodes by a predetermined number of electrode slides so that some electrodes overlap, thereby maintaining the coupled electrodes in a state where the maximum number of coupled electrodes is maintained. A capacitance detection unit for detecting the capacitance of the electrode at the end and the coupling electrode, A position calculation unit calculates the proximity or contact position of the object to be detected based on the capacitance detected by the capacitance detection unit. A proximity detection device equipped with the following features. (Note 2) The proximity detection device according to Appendix 1, characterized in that a predetermined number of electrodes are sequentially coupled from one end of the touch panel, and the electrodes are repeatedly separated and coupled by a predetermined number of electrode slides so that some electrodes overlap when the predetermined maximum number of coupled electrodes is reached, thereby maintaining the maximum number of coupled electrodes, and at predetermined positions leading up to the other end, the coupled electrodes with the maximum number of coupled electrodes are sequentially separated by the predetermined number of electrode slides. (Note 3) The proximity detection device according to Appendix 1 or 2, characterized in that it calculates the magnitude of the change in capacitance detected by the capacitance detection unit and determines the maximum number of electrode connections such that the magnitude of the detected change in capacitance remains constant, according to the size of the touch panel and the size of the electrodes. (Note 4) The proximity detection device according to any one of the appendices 1 to 3, characterized by comprising a control unit that instructs the electrode control unit to connect and disconnect the electrodes, calculates the magnitude of the change in capacitance detected by the capacitance detection unit, and outputs it to the position calculation unit. [Explanation of Symbols]

[0035] 10: Proximity detection device, 1, 11: Touch panel, 12: Electrode control unit, 13: Capacitance detection unit, 14: Control unit, 15: Position calculation unit, 100: Processor, 200: Memory device

Claims

1. A touch panel having multiple electrodes whose capacitance changes upon proximity to and contact with an object to be detected. An electrode control unit that sequentially increases electrodes in a predetermined direction from the electrode at the edge of the touch panel to form coupled electrodes, and when the maximum number of coupled electrodes is reached, repeatedly separates and combines the electrodes by a predetermined number of electrode slides so that some electrodes overlap, thereby maintaining the maximum number of coupled electrodes. A capacitance detection unit for detecting the capacitance of the electrode at the end and the coupling electrode, A position calculation unit calculates the proximity or contact position of the object to be detected based on the capacitance detected by the capacitance detection unit. Equipped with, The proximity detection device is characterized in that the maximum number of electrode couplings is determined by calculating the magnitude of the change in capacitance detected by the capacitance detection unit, and determining the number of couplings such that the magnitude of the detected change in capacitance remains constant, according to the size of the touch panel and the size of the electrodes.

2. The proximity detection device according to claim 1, characterized in that a predetermined number of electrodes are sequentially coupled from one end of the touch panel, and the coupling and uncoupling of electrodes is repeated by a predetermined number of electrode slides so that some electrodes overlap when the maximum number of coupled electrodes is reached, thereby maintaining the maximum number of coupled electrodes, and at predetermined positions leading up to the other end, the coupled electrodes with the maximum number of coupled electrodes are sequentially separated by the predetermined number of electrode slides.

3. The proximity detection device according to claim 1 or 2, further comprising a control unit that instructs the electrode control unit to connect and disconnect the electrodes, calculates the magnitude of the change in capacitance detected by the capacitance detection unit, and outputs it to the position calculation unit.

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