Patent Application
20170192555
1. Field of the Invention
The invention relates to a touch device, and particularly relates to a capacitive touch device and a detection method of a capacitive touch panel thereof.
2. Description of Related Art
Information technologies (ITs), wireless mobile communication, and information home appliances have been rapidly developed and widely applied. To meet current demands of being portable, compact, and user-friendly, touch panels have been adopted as input device in replacement of conventional keyboards or mice in many electronic devices. Currently, touch panels can be categorized into capacitive touch panels and resistive touch panels. Due to its better sensing effect, the capacitive touch panels have become the mainstream of touch panels nowadays.
Capacitive touch panels mainly rely on capacitance variation of touch electrodes to detect a touched point, and electrical properties of a capacitive touch panel may be influenced by process and stack structure. When the equivalent capacitance variation of the capacitive touch panel is too low, the touched point may not be accurately detected. Thus, how to accurately detect the touched point when the equivalent capacitance variation of the capacitive touch panel is too low remains an issue in the development of touch panel.
The invention provides a capacitive touch device and a detection method of a capacitive touch panel thereof capable of increasing a capacitance variation of a touch electrode when a finger or a touch pen touches.
An embodiment of the invention provides a capacitive touch device. The capacitive touch device includes a plurality of touch electrodes, a detector unit, a plurality of switch units, and a touch point determination unit. The detector unit detects the touch electrodes and provides a plurality of capacitances. The switch units are coupled to the detector unit and the touch electrodes and receive a ground voltage. The switch units couple the detector unit to the touch electrodes and provide the ground voltage to the touch electrodes not coupled to the detector unit. The touch point determination unit is coupled to the detector unit, determines whether the touch electrodes are touched based on the capacitances, and correspondingly provides touch information.
An embodiment of the invention provides a detection method of a capacitive touch panel. The capacitive touch panel is located in a capacitive touch device. The method includes steps as follows. A detector unit and a plurality of touch electrodes are coupled through a plurality of switch units, and a ground voltage is provided to the touch electrodes not coupled to the detector unit through the switch units. The touch electrodes are detected by using the detector unit and a plurality of capacitances are provided. Whether the touch electrodes are touched based on the capacitances is determined by using a touch point determination unit, and touch information is correspondingly provided based on whether the touch electrodes are touched.
Based on above, in the capacitive touch device and the detection method of the capacitive touch panel thereof according to the embodiments of the invention, the touch electrodes that are not coupled to the detector unit are coupled to the ground voltage, so that the touching finger or touch pen forms the equivalent capacitances with the grounded touch electrodes. Accordingly, the capacitance variation of the touch electrode is increased when the finger or the touch pen touches.
In order to make the aforementioned and other features and advantages of the invention comprehensible, several exemplary embodiments accompanied with figures are described in detail below.
The accompanying drawings are included to provide further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments and, together with the description, serve to explain the principles of the disclosure.
Reference will now be made in detail to the embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
Each of the switch units (e.g., 120_1 to 120_x) is coupled to the detector unit 130 and one of the touch electrodes TE, and receives a ground voltage GND. When the electrical touch panel 110 scans, at least one switch unit (e.g., 120_1 to 120_x) couples the detector unit 130 to the corresponding touch electrode TE, and rest of the switch units (e.g., 120_1 to 120_x) provide the ground voltage GND to the corresponding touch electrodes TE. Namely, the touch electrodes TE that are not coupled to the detector unit 130 are coupled to the ground voltage GND. When the electrical touch panel 110 does not scan (i.e., in an idle state), the switch units 120_1 to 120_x may provide the ground voltage GND to all the touch electrodes TE or make all the touch electrodes TE in a floating state, depending on an arrangement made by people having ordinary skills in the art.
After the detector unit 130 is coupled to the touch electrode TE, the touch electrode TE that is coupled is detected. In addition, after detection, the detector unit 130 may provide a multiple-bit logical value VLC to represent a current equivalent capacitance of the touch electrode TE. Namely, each of the touch electrodes TE corresponds to a logical value VLC. The touch point determination unit 140 is coupled to the detector unit 130, so as to receive the logical values VLC corresponding to all the touch electrodes TE. In addition, when the touch point determination unit 140 receives the corresponding logical values VLC of all the touch electrodes TE, the touch point determination unit 140 may determine whether the touch electrodes TE are touched based on the capacitances represented by the logical values VLC and correspondingly provide touch information Itou.
Referring to
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In the above embodiment, the detector unit 130 includes an analog-to-digital converter, for example. However, in other embodiments, the detector unit 130 may include a plurality of analog-to-digital converters to detect the touch electrodes TE at the same time and provide the corresponding logical values VLC. The touch electrodes TE that are not detected are coupled to the ground voltage GND. Accordingly, the number of analog-to-digital converters may be reduced to reduce a hardware cost of the capacitive touch device.
Besides, scanning of the respective groups (e.g., GP1 to GP4) may be synchronized. Namely, detection directions of the touch electrodes TE of the respective groups (e.g., GP1 to GP4) may be completely the same. In other words, the detection directions of the touch electrodes TE of the respective groups (e.g., GP1 to GP4) may be in a Z-shape or N-shape synchronous scanning pattern from the upper left corner to the lower right corner of the figure. Alternatively, the scanning of the respective groups (e.g., GP1 to GP4) may not be synchronized. Namely, the detection directions of the touch electrodes of the respective groups (e.g., GP1 to GP4) may not be exactly the same. In other words, the detection directions and starting positions of the touch electrodes TE of the respective groups (e.g., GP1 to GP4) may be arbitrarily set. The embodiments of the invention are not limited thereto. When the scanning of the respective groups (e.g., GP1 to GP4) proceeds synchronously, equivalent capacitance structures of the detected touch electrodes TE are approximately the same, so as to approximate capacitance variations of the capacitive touch panel (e.g., 110).
In view of the foregoing, in the capacitive touch device and the detection method of the capacitive touch panel thereof according to the embodiments of the invention, the touch electrodes that are not coupled to the detector unit are coupled to the ground voltage, so that the touching finger or touch pen forms the equivalent capacitances with the grounded touch electrodes. Accordingly, the capacitance variation of the touch electrode is increased when the finger or the touch pen touches so as to enhance the touch sensitivity of the touch device and the identification of the touch point.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of the disclosure provided they fall within the scope of the following claims and their equivalents.
